Table of Contents · APP. Groundwater restoration will never be accomplished within the short term of the Temporary APP. And when Curis fails to restore groundwater to pre-mining

Comments on Curis Resources’ Application for a

Temporary Aquifer Protection Permit

September 21, 2012

i

Table of Contents

1 Introduction and Background. ................................................................................1

1.1 ADEQ Must Protect The Drinking Water Aquifer. ...................................... 2

1.2 This Is Not Your Typical Mine. ....................................................................... 4

1.2.1 Exploration, Testing, & Permit Issuance ................................................ 4

1.2.2 After the Mine Companies Abandoned the Site, a New Owner

Requested Annexation & Rezoning by the Town of Florence. .... 5

1.2.3 The Merrill Ranch Master Planned Community Becomes Reality. .... 6

1.2.4 Curis Comes to Town in 2009 & Tries to Convince Everyone that It’s

1997. ...................................................................................................... 8

1.2.5 The Town of Florence Says No to Curis. .............................................. 10

1.2.6 The Neighbors Don’t Want a Mine. ...................................................... 11

2 This Is Not a Pilot But Instead Commercial Mining Phase 1. ...........................13

3 Best Available Design and Control Technology—Injection Well Field ...........18

3.1 Curis Cannot Satisfy ADEQ’s BADCT Requirements for Injection Wells

Because it Proposes to Inject Acidic Mining Solutions Directly Into a

Drinking Water Aquifer. ............................................................................. 18

3.1.1 The LBFU is a major drinking water supply for the Town of

Florence. ............................................................................................. 20

3.1.2 The Middle Fine Grained Unit does nothing to protect the drinking

water aquifer. .................................................................................... 23

3.1.3 Curis proposes to inject acid mining solutions into a highly fractured

ore body. ............................................................................................ 25

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3.1.4 Loss of hydraulic control could allow acidic solution to migrate from

the ore body into both the LBFU and UBFU. ............................... 31

3.2 Curis’s Well Field Design Has Not Been Shown to Prevent Acid Mining

Solutions from Polluting the Drinking Water Supply. ........................... 33

3.2.1 Curis does not propose to demonstrate that it can maintain

hydraulic control during Commercial PTF operations. .............. 33

3.2.2 Curis’s Commercial PTF well field design differs significantly from

the design proposed for commercial production. ....................... 34

3.2.3 Curis fails to demonstrate that the 40-foot exclusion zone will protect

the drinking water supply and fails to account for the site

specific geology present in the steep interface between the LBFU

and oxide units. ................................................................................. 36

3.2.4 Curis’s placement of observation wells in the Commercial PTF well

field is designed to succeed but does not replicate commercial

production. ........................................................................................ 38

3.2.5 Curis’s description of proposed methods for determining hydraulic

control cannot be used for the Commercial PTF.......................... 39

3.2.6 Curis has not demonstrated that it can maintain hydraulic control to

overcome vertical groundwater gradients in the Commercial

PTF. ..................................................................................................... 40

3.2.7 Curis’s well field design fails to account for known groundwater

mounding near the Commercial PTF well field. .......................... 41

3.2.8 Curis has not justified use of a five-spot well pattern. ....................... 43

3.3 Curis Has Not Adequately Addressed Man-Made Preferential Pathways

for the Escape of Acid Mining Solutions. ................................................. 44

3.3.1 Curis’s mine site contains hundreds of core holes, most of which

have never been located. ................................................................. 47

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3.3.2 Underground Mine Workings are Key Geologic Features that Have

Not Been Adequately Considered. ................................................ 56

3.3.3 Curis has not addressed the impacts of on-site wells. ........................ 61

3.4 Curis Failed to Consider Alternative Discharge Control Measures. ....... 64

3.5 Curis Failed to Consider Alternative Sites and Properly Evaluate Site-

Specific Criteria. ........................................................................................... 65

4 Best Available Design and Control Technology—Runoff Pond .......................68

4.1 ADEQ Should Closely Scrutinize Curis’s Use of Prescriptive BADCT in

an Area of Known Instability. .................................................................... 68

4.2 ADEQ Should Require Additional Clarification Regarding Curis’s

Intended Uses of the Runoff Pond. ........................................................... 69

5 Curis Has Failed to Demonstrate that It Can Comply with AWQS at the

Appropriate POC. ....................................................................................................71

5.1 Curis’s Proposed POC Wells Fail to Protect Drinking Water Uses. ........ 71

5.1.1 Drinking Water is the Aquifer’s Current and Reasonably Foreseeable

Future Use. ........................................................................................ 71

5.1.2 POC Wells Are Not Located to Protect the Aquifer for Drinking

Water Uses. ........................................................................................ 73

5.1.3 Curis’s Overall POC Well Field Design Is Based Upon Convenience

to Curis, Rather Protecting the Aquifer for Drinking Water Uses.

............................................................................................................. 80

5.2 Proper ALs, AQLs, & Narrative Standards Should Be Established To

Protect the Aquifer for Drinking Water Uses. ......................................... 82

5.2.1 Curis’s proposed arsenic limit pushes the cost of SDWA-mandated

treatment downstream to drinking water providers. ................. 84

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5.2.2 Curis’s sulfate proposal is inconsistent with the Safe Drinking Water

Act’s Secondary MCL for sulfate and the concomitant public

health risks of nearby sensitive populations. ............................... 84

5.2.3 A Sulfate Standard of 750 mg/L Allows Curis to Pass Groundwater

Treatment Costs Along to Downgradient Water Users. ............. 86

5.2.4 ADEQ Should Establish a Narrative Sulfate Standard in the APP of

200 mg/L............................................................................................. 87

5.2.5 Alert Levels Should Be Established for Other Pollutants Without

AWQSs. .............................................................................................. 89

5.3 Curis’s Proposal for Monitoring of Pollutants Is Offensively Inadequate.

........................................................................................................................ 90

5.4 ADEQ Should Require Curis to Provide Notice of Exceedances of APP

Standards to the Public. .............................................................................. 91

6 The BHP Pilot Raised More Questions Than It Provided Answers. ................92

6.1 Groundwater Exceedances Should Not Be Ignored. .................................. 94

6.1.1 Present-Day Groundwater Exceedances. ............................................. 94

6.1.2 Other Post-BHP Pilot Test Groundwater Exceedances. ................... 101

6.2 Radiochemical Exceedances Should Not Be Ignored. .............................. 103

6.2.1 Arizona Copper Mines Generally Mobilize Radiochemicals in

Groundwater and Concentrate Radiochemicals in Process and

Waste Streams. ................................................................................ 104

6.2.2 Curis’s ISL Mining Will Concentrate and Leach Naturally Occurring

Uranium Into the Aquifer. ............................................................ 107

6.2.3 Curis’s ISL Mining Process Is Used Around the World to Mine

Naturally Occurring Uranium. ..................................................... 110

6.2.4 This Site Has Had a 10-Year History of Repeated High Level

Radiochemical Results. .................................................................. 112

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6.2.5 Curis Completely Ignores Radiochemical Concentrations in Process

Streams, Waste Streams, and the Impoundment Pond. ........... 120

6.2.6 Conclusion .............................................................................................. 120

6.3 Increasing Sulfate Trends in the Proximity of the Previous Well Field

Raise Concerns About the Impacts of the BHP Pilot. ........................... 122

7 Curis’s Commercial PTF Is Premised on Fundamentally Flawed Computer

Modeling That Fails to Recognize Real World Conditions. ............................125

7.1 Conceptual models for simulating contaminant flow and transport at the

site level have not been adequately developed. .................................... 126

7.2 The models have not been sufficiently calibrated for making

contaminant flow and transport predictions at the site level.............. 127

7.3 The UIC Model may be too simple to simulate site conditions, making it

unsuitable to demonstrate that hydraulic control will be maintained

and contaminants will not migrate away from the site. ...................... 131

7.4 Geochemical Evaluation of Forecast Process Solutions ........................... 131

8 Curis’s Proposals for Cleaning Up its Groundwater Pollution Are Overly

Optimistic. ..............................................................................................................133

8.1 A Federal Report on Uranium ISL Mines in Texas Concluded That Mine

Operators Could Not Restore Groundwater to Pre-Mining Levels. .. 135

8.2 Pollutant Rebound Can Take Months or Years to Detect and Address. 138

8.3 ISL Uranium Mines Have Experienced Significant Difficulty With

Groundwater Restoration ......................................................................... 139

8.3.1 Crow Butte In-Situ Leach Uranium Mine, Dawes County, Nebraska

........................................................................................................... 139

8.3.2 Smith Ranch-Highland In-Situ Uranium Mine, Converse County,

Wyoming ......................................................................................... 143

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8.3.3 Irigaray-Christensen Ranch In-Situ Uranium Mine, Johnson County,

Wyoming ......................................................................................... 147

9 Curis Has Not Complied with the Financial Capability Demonstration

Requirement for an APP. ......................................................................................151

9.1 Regularly updated and re-evaluated costs are key. ................................. 154

9.2 Curis Should Provide Up-Front Financial Assurance Mechanisms and

Contingencies to Address Off-Site Contamination. ............................. 155

10 ADEQ Should Carefully Scrutinize Curis’s Predictions of Environmental

Safety. ......................................................................................................................156

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1 Introduction and Background.

Several years ago, SWVP purchased land inside the municipal limits of the Town

of Florence and adjacent to Curis’s property. Curis bought land encompassing the Pilot

at approximately the same time. Both SWVP’s and Curis’s property are part of the

Merrill Ranch Master Planned Community within the Town of Florence’s municipal

boundaries and under which residential and commercial—not mining—uses are

allowed. As you are aware, Curis’s requested Temporary APP covers a 160-acre parcel

leased by Curis from the State Land Department. This relatively small parcel in the

northern portion of Curis’s property is part of Curis’s Florence land holdings and is the

only portion to which the Town of Florence’s zoning does not apply. As evidenced by

recent votes of the Town of Florence’s Council and elections of Town leaders, Curis will

never be permitted to mine in areas of its property within the Town’s jurisdiction.

Curis’s application for a Temporary APP on a small parcel that it leases from the State

Land Department is nothing more than an attempt to avoid the Town’s opposition to its

mining plans and to avoid deeper inquiry into the safety and feasibility of its proposed

project. ADEQ’s primary obligation is to protect the health and safety of the people and

environment of Pinal County and the Town of Florence. ADEQ should not permit itself

to be used as a tool to further Curis’s aims. Unfortunately, in allowing Curis to pursue

a Temporary APP, ADEQ has permitted numerous significant issues to be swept under

the rug and has ignored public comments and concerns.

A Temporary APP is inappropriate at best and illegal at worst in this case. Curis

should be required to continue with its February 2011 significant permit amendment

application, which already covered its proposal for a commercial production test facility

(Commercial PTF). Even if it were appropriate, the Temporary APP does not contain

the level of detail and the stringent conditions necessary to protect the aquifer from

Curis’s injection of sulfuric acid into a drinking water aquifer. It is unlikely that the

true impacts of the Commercial PTF will be known during the term of the Temporary

APP. Groundwater restoration will never be accomplished within the short term of the

Temporary APP. And when Curis fails to restore groundwater to pre-mining

conditions, nothing in the Temporary APP ensures that Curis will provide the financial

and other resources to address the contamination it has caused. Making matters even

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worse is the fact that Curis’s justification of the Commercial PTF as a demonstration

that ISL mining at this site is environmentally safe is a sham, and ADEQ has in essence

acknowledged the same. Curis has admitted that it plans to secure its commercial

permits prior to the conclusion and full evaluation of the Commercial PTF. And ADEQ

has acknowledged that it intends to allow Curis to do just that. As a result Curis and

ADEQ apparently intend to move forward with commercial production at this site

before environmental data from the Commercial PTF is available to prove or disprove

whether ISL mining can be done without impact to the environment. For the reasons

discussed in detail within these comments and in the attached documents, ADEQ

should deny the requested Temporary Permit and require Curis to pursue its

Commercial PTF under the existing significant permit amendment application

including thorough agency review and proper public notice and comment.

1.1 ADEQ Must Protect The Drinking Water Aquifer.

In 1986 the State of Arizona adopted the Environmental Quality Act, created the

Arizona Department of Environmental Quality, and recognized the precious and

delicate nature of groundwater within this desert state by designating all its aquifers as

drinking water aquifers. Along with that designation, Arizona enacted the Aquifer

Protection Permit program, a landmark program when passed, as a way to proactively

protect our state’s precious groundwater from contamination. Because there has been

no re-designation of the aquifer within and surrounding Curis’s proposed mine, the

State has a responsibility to ensure that this aquifer is protected for drinking water uses.

Not only did the legislature recognize the importance of our drinking water

aquifers, but ADEQ also recognized this important resource and adopted agency goals,

missions, and a vision supporting its role as protector of Arizona’s precious

groundwater. ADEQ’s vision is to lead Arizona and the nation in protecting the

environment and improving the quality of life for the people of our state, and its stated

mission is to protect and enhance public health, welfare and the environment in

Arizona. One of the ways that the agency plans to accomplish its vision is by

advocating for Arizona’s environment.1 It is ADEQ’s responsibility to look out for

1 ADEQ Website, http://www.adeq.gov/function/about/download (last visited June 11, 2012).

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Arizona’s environment and advocate for its water, land and air so that Arizona

residents’ quality of life is improved.

ADEQ has a responsibility to protect the groundwater, especially in the complex

hydrogeologic area encompassing Curis’s proposed Commercial PTF. Curis’s proposed

project is not your typical mine. This permit is the first step in commercial in-situ

copper mining, a mine which we have yet to see even attempted in this country. In fact,

when ADEQ asked Curis to provide an example of a similar operation, Curis failed to

do so, in essence admitting that commercial ISL mining has never been conducted.2

Not only is this a novel type of mine, but a review of Curis’s submittals reveals that

Curis really understands very little about this complex hydrogeologic area and the

potential impacts of its proposed in-situ mine. The bulk of Curis’s application is merely

a repackaged version of old materials – old studies, evaluations and reports conducted

by previous property owners or project proponents over 15 years ago. In fact, Curis

admits that ‚no significant additional hydrogeologic characterization activities have

been conducted at the PTF site and surrounding vicinity since the Brown and Caldwell

(1996a) study was completed.‛3 As will be explained in more detail within these

comments, the area surrounding the proposed mine has drastically changed since 1996.

We beseech ADEQ to require Curis to conduct thorough and comprehensive

investigations of the site and surrounding area to support its application. Don’t let

Curis get away with relying on outdated information to secure a novel mining permit.

Instead, fulfill your responsibility to protect this drinking water source by denying the

requested Temporary Permit in its entirety.

For ADEQ to issue this Temporary Permit, Curis must demonstrate both that (1)

the facility will be designed, constructed and operated as to ensure the greatest degree

of discharge reduction achievable through application of BADCT (best available

demonstrated control technology), processes, operating methods or other alternatives,

including, where practicable, a technology permitting no discharge of pollutants; and

that (2) pollutants discharged will in no event cause or contribute to a violation of

2 See Curis’s Response to ADEQ’s Request for Information (May 23, 2012), Response to

Comment 3. 3 Curis Resources (Arizona) Inc., Application for Temporary Individual Aquifer Protection

Permit (March 1, 2012) (Temporary Application) at 14A.3.1.

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aquifer water quality standards (AWQS) at the point of compliance (POC) or further

degrade aquifer quality at the POC if at the time of permit issuance the AWQS are

already exceeded.4 As will be explained more fully herein, Curis has failed to

demonstrate these statutory requirements and, therefore, ADEQ can and should deny

the requested Temporary Permit.

1.2 This Is Not Your Typical Mine.

1.2.1 Exploration, Testing, & Permit Issuance

This site has a long history of exploration followed by inactivity and property

transfers. Once again, another company has acquired the site and has begun the

exploration and testing cycle, seeking agency approvals for a pilot test. Beginning in

late 1974, Continental Oil Company (Conoco) conducted an underground copper

mining pilot project, drilling hundreds of core holes in an effort to determine the

feasibility of open-pit copper mining in the area. Conoco also excavated a series of

underground shafts on the State Land parcel. Neither the core holes nor the shafts were

properly closed and abandoned. Later in time, Conoco conducted another test, this

time an experimental leach agitation process with gold bearing ore. In 1977, Conoco

vacated the site.

The site then sat idle for 15 years until Magma Copper Company acquired and

began studying the site. As part of their exploration and testing efforts, Magma applied

for both underground injection control (UIC) and APP permits. But by the time of

permit issuance, there had been another change in property owner resulting in Broken

Hill Proprietary (BHP) as the permitee. These permits allowed pilot testing to once

again begin. So in late 1997, BHP began a pilot to test the concept of in-situ hydraulic

control. This test lasted only 90 days with BHP walking away before completing a final

pilot evaluation report. BHP never did mine this site, instead completely abandoning

the property in the early 2000s.

4 Ariz. Rev. Stat. § 49-243(B).

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1.2.2 After the Mine Companies Abandoned the Site, a New Owner

Requested Annexation & Rezoning by the Town of Florence.

After BHP left the site, Harrison Merrill purchased the property and joined other

property owners in petitioning the Town of Florence to be annexed into the Town. The

Town acquiesced with that petition, and in late 2003, passed Ordinance No. 354-03,

formally extending the Town’s corporate limits more than 8,000 acres to include the

vast majority of the site at issue in this dispute.5 As part of the change in land use,

during 2007, just two years before Curis would buy the property, Mr. Hugh Nowell,

Executive Vice President of WHM Merrill Ranch Investments, LLC, signed a consent

permitting the Town to rezone the property to Planned Use Development (PUD) status

– a land use category that proscribed mining.6 A Zoning Ordinance was adopted by

the Town in 2007 formally modifying the property’s zoning to PUD – a zoning category

that prohibited mining.7

In accordance with the PUD zoning, Town officials, along with property owners

and community members, developed the Merrill Ranch Master Plan which established

zoning for much of the newly annexed area allowing for homes, schools, open spaces

and parks, and commercial uses.8 Notably, nowhere in this master planned community

was mining permitted. This zoning was part of the Town of Florence’s General Plan

which, in accordance with State law, was put to a vote of the people and approved by

the Florence voters. Development to date has followed this plan and residential

neighborhoods now flourish within only 1.5 miles of Curis’s proposed mine and more

homes are planned within less than one-half mile of the mine. For your reference, we

have attached a map showing the incorporated boundaries of the Town of Florence.9

5 Although the State Land Department supported the Town’s efforts, the actual 160-acre State

parcel was not annexed into the Town. See Town of Florence Ordinance No. 354-03 (Dec. 15,

2003).

6 Consent to Conditions/Waiver for Diminution of Value (March 21, 2007).

7 Town of Florence Ordinance No. 460-07 (June 4, 2007) (applicable to the site at issue with the

exception of the State land parcel).

8 See Attachment A, Merrill Ranch Master Plan.

9 See Attachment B, Town of Florence Boundaries (Curis’s proposed mine is located north of the

Gila River within the vicinity of the light colored rectangle and south of the Hunt Highway).

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Although the 160-acre State land parcel is not subject to municipal zoning, it is

completely encircled by land within the Town of Florence’s boundaries and zoned as

master planned community. The land is subject to a State land lease for mining that is

up for renewal in December 2013. And correspondence from the previous landowner

casts doubt on whether mining is even a viable option for the site. In response to

apparent interest by another mining venture, then-owner Harrison Merrill wrote that

an October 1999 Draft Field Test Report evaluating the BHP pilot actually demonstrated

that mining the site was not a viable endeavor. The report apparently indicated low

copper recovery rates that could require leaching for 6 to 8 years to obtain economically

viable copper recovery of 60% to 65%. According to the letter, the report also indicated

that methods to increase copper production at the site would exacerbate water quality

problems with low pH and that it could cause heavy metal and radiological

groundwater contamination. The letter goes on to voice concerns about potential

impacts to neighboring properties from any site mining. Although SWVP has

requested this report from ADEQ, ASLD and the EPA, the report appears to have

vanished with each agency unable to locate the report. And Curis has never even

mentioned the existence of a Draft Field Test Report, instead apparently ignoring its

existence and claiming the pilot as a success.

1.2.3 The Merrill Ranch Master Planned Community Becomes Reality.

Not only was the site annexed and rezoned, but the neighboring area also

became part of the Town, was rezoned, and was transformed into a master planned

community. Where once there was dirt and scrub brush, now there is a community

with retirement communities, family neighborhoods, pools and a water park, and a golf

course. In fact, Where to Retire Magazine recently named one of the existing

neighborhoods, Sun City Anthem by Del Webb at Merrill Ranch, as one of the top 50

best communities in the nation to retire.10 Pulte began developing the Anthem

community in 2004, five years before Curis ever came to town. In 2004, Pulte Homes

bought over 3,000 acres of land, more than 2,000 acres of which were from Harrison

Merrill. This transaction would later become the Anthem community, the result of

10 July/August 2011 edition.

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more than $400 million dollars invested by Pulte into the community spent in reliance

on the Town-approved Merrill Ranch Master Plan.

Building permit statistics provide further evidence of this vastly changed area.

In 1990 there were only 129 permits issued but that number grew to 556 permits by

2008.11 Much of the remaining open desert areas have since been annexed into the

Town and are slated for continued master plan community development. And with the

Town’s development came an enormous population boom. According to the Arizona

Department of Commerce, the Town’s year 1990 population was only 7,321 but grew to

14,466 by the year 2000. And by 2008, the Town of Florence was home to 24,096

people.12 Taxable sales also greatly increased from $12.3 million in 1990 to $102 million

in 2000 and finally to $281.3 million by 2008.13

The Town also continued to develop its vision of this expanded, transforming

area. Historic Florence downtown district redevelopment efforts were updated in 2009

and incorporated concepts designed to unite the areas south and north of the Gila River

within the vicinity of Curis’s proposed mine. The Town’s redevelopment plan is

centered around three core areas, the Historic Core, the South Gateway, and, closest to

Curis’s property, the North End.14 The Town’s vision for the North End is to extend the

Historic Core, the heart and soul of the Town, while incorporating innovative and

sustainable buildings and spaces. According to the Town, ‚Florence has made a

significant investment in land between the Historic Core and the Gila River. This

investment becomes the seat of government for the Town and in the future, the

County.‛15 Part of the Town’s vision and plans is to connect the newer northern portion

of the town – the Merrill Ranch Master Planned Community – with downtown

11 Arizona Department of Commerce, Florence Community Profile, available at

http://www.azcommerce.com/doclib/commune/florence.pdf.

12 Arizona Department of Commerce, Florence Community Profile, available at

http://www.azcommerce.com/doclib/commune/florence.pdf (based upon Revised Census

figures).

13 Id.

14 See Attachment C, Florence Redevelopment Area and Districts Figure, from Town of Florence

Downtown Redevelopment Plan Update, Figure 1-1 (Feb. 2009).

15 Id. at 2-12.

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corridor.16 Sandwiched in between the Merrill Ranch Master Planned Community and

Florence’s Historic Core is Curis’s proposed mine, blocking the Town’s plans to link the

historic downtown redevelopment area with the communities north of the river.

Along with the community’s planning efforts, came renewed investments in

infrastructure and utilities to support the ongoing and future development. To support

the growing and spreading population, Johnson Utilities expanded its operations to

serve the population north of the Gila River including Pulte’s Anthem community.

According to Johnson representatives, the drinking water provider serves

approximately 30,000 homes and is only twenty percent built out.17 The Town of

Florence itself also anticipated the need for additional water supplies, especially in the

areas north of the Gila River,18 and began planning to meet those needs. Significantly,

the Town’s proposed wells are planned to be constructed at the same depth as Curis’s

wells.19

Southwest Value Partners moved into the area in December 2009. Together with

a purchase a short time later, SWVP would acquire over 4,000 acres within the Merrill

Ranch Master Planned Community. This land houses several existing groundwater

wells including a 1,180 foot deep irrigation well just outside Curis’s western property

border.20

1.2.4 Curis Comes to Town in 2009 & Tries to Convince Everyone that It’s

1997.

In December 2009, Curis purchased the property at issue through a ‚blind‛

transaction, one that kept its identity and purpose secret. Even though the site had not

experienced any actual mining, an APP permit still existed and in the spring following

16 See Id.

17 See Attachment D, Water Production Well Location Map (depicting in red the Johnson Service

Area).

18 The Gila River crosses through the Town’s current footprint, with the historic downtown

district south of the River and Curis’s property north of the River.

19 See Attachment E, Area Wells and Aquifer Depth Figure.

20 See Attachment F, Cross-Section Depicting Nearby Well Depths.

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Curis’s property acquisition, Curis asked ADEQ to simply change the permit owner’s

name to Curis. As Curis proposed, this name change would have allowed Curis to

operate a pilot test under an ‚Other Amendment,‛ a permit action without public notice

and involvement. ADEQ recognized the attempt for what it was and did not approve

Curis’s request, instead requiring submission of a ‚Significant Amendment‛

application, an action which would require much more extensive review, public notice,

and public input. Curis relented and in 2011 submitted a request for a Significant

Amendment to APP No. 101704 – this time for the full project including a Phase I pilot

and Phase II commercial operations.

But it would not be a simple road because ADEQ asked questions, lots of

questions. On Sept. 11, 2011 ADEQ sent Curis a Comprehensive Request for Additional

Information (September Deficiency Letter) which was 25 pages long and included over

88 identified deficiencies. Among the concerns noted by the agency were those related

to the 1997 pilot test, groundwater conditions after pilot rinsing activities, radioactive

chemical concentrations in groundwater, underground workings & core holes that

could lead to excursions, whether there would be enough water available for solution

mining now or in the near future and many other probing questions. Shortly after the

Deficiency Letter was issued, Curis publicly proclaimed that they would be able to

answer all the agency’s questions in short order. But as of the date of these comments,

Curis has yet to answer ADEQ’s Deficiency Letter. Instead, Curis requested that ADEQ

put their review of Curis’s application on hold. On Dec. 20, 2011 Curis submitted a

letter to ADEQ requesting that the agency suspend its review of Curis’s substantial

modification application to allow Curis to pursue a temporary permit. Instead of

answering the agency’s questions so that review of the Substantial Amendment

application could continue, Curis seeks again what the agency already denied –

approval of the pilot project without a Significant Amendment.

This time, Curis chose the Temporary Permit route, another avenue avoiding

more rigorous agency review and public input. Two months after Curis submitted its

application, ADEQ sent Curis a Deficiency Letter (May Deficiency Letter) to which

Curis responded during that same month. ADEQ later declared Curis’s response

inadequate.

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The mine also needed approval at the federal level, and Curis began petitioning

USEPA to simply transfer the exemption and permit from BHP to itself. It didn’t work.

After considering the history of the site and the long period of inactivity accompanied

by a vastly changing landscape, USEPA not only denied Curis’s request but revoked the

then-existing approval and told Curis to reapply. In the denial letter EPA specifically

noted the ‚substantial lapse in time since the existing permit was issued, the absence of

any permitted activity at the site over the last ten years, and the new information

regarding residential development in the area.‛ Curis relented and on March 25, 2011

submitted its UIC application (No. AZ396000001). About 10 months into its technical

review, USEPA issued a Request for Information to Curis requiring additional

information before the agency could continue their technical review of Curis’s

application. Curis responded to USEPA’s RFI and EPA’s technical review continues.

Most recently Curis requested that USEPA focus its review on the Phase 1 Commercial

PTF portion of its UIC application.

1.2.5 The Town of Florence Says No to Curis.

Because Curis’s private land holdings were not zoned for mining, Curis

requested various land use changes from the Town of Florence. In response, the Town

of Florence Planning and Zoning Commission held two lengthy public hearings on

Curis’s proposed General Plan Amendment—a prerequisite to the zoning changes

Curis needs. The first hearing held on September 15, 2011 attracted approximately 300

people and went well into the early morning hours of the following day. The second

hearing on October 6, 2011 was once again filled to capacity with more interested

members of the public standing outside in the cold or nearby in overflow rooms. At

this hearing, 137 Florence residents submitted comment cards in opposition to the

proposed mine. At the conclusion, the Commission did not forward a favorable

recommendation to amend the Town’s General Plan on either of Curis’s two

applications to Town Council. Despite Curis’s later attempts to withdraw their General

Plan Amendment application prior to the scheduled Town Council hearing on

November 7, 2011, the Town Council denied their request for withdrawal on their main

application and held a hearing on the matter. At this hearing 124 Florence residents

submitted comment cards in opposition to the project, while only 34 Florence residents

submitted cards in support. In addition, Johnson Utilities, which provides water to the

area also appeared in opposition and voiced many valid environmental concerns. At

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September 21, 2012

11

the conclusion of the hearing, the Florence Town Council unanimously denied Curis’s

requests by a 7-0 vote. Notably, each council member publicly stated that the proposed

mine was contrary to the best interests of Florence residents in the short or long term

and that the mine would negatively alter the character of Florence in a dramatic fashion.

This did not, however, end the local community’s input and the Town’s desire to

communicate their message that a Mine does not belong in the middle of a master

planned residential community. Instead, prompted by the significant public outcry

against the Mine, the Town Council passed Resolution No. 1324-11, expressing strong

opposition to the Mine and pronouncing as ill-advised, a mine along the Gila River in

close proximity to populated areas and a vital aquifer.21 These conclusions were made

after the Town, itself a water provider with designated Assured Water Supply status

and a Designated Management Agency with Clean Water Act implementation and

enforcement authority, considered the health and safety and environmental risks of in-

situ mines and the unacceptable economic impacts associated with the legacy of in-situ

mining. Further, the Town expressed its view that Curis’ Mine was inconsistent with

the guiding principles and overall vision of the voter-approved Florence General Plan

2020. This Resolution expressly urges all reviewing agencies to reject any applications

which would aid the mine in locating within the Town boundaries of Florence.

1.2.6 The Neighbors Don’t Want a Mine.

SWVP is not alone in being concerned about the mine’s potential environmental

impacts and opposing the mine. Pulte which invested substantial dollars into the

Anthem community, Johnson Utilities, residents that call Florence home, and other

property owners in the area are all concerned about the impacts of the proposed mine.22

Another neighbor, the Gila River Indian Community, is so vehemently opposed to a

mine in such close proximity to the Community, its residents, and its water that they

adopted a resolution formally opposing the mine. Despite the awareness of the intense

public concern with this project, ADEQ only held an ‚open house‛ that was not a forum

21 Town of Florence Resolution No. 1324-11 is enclosed as Attachment G.

22 Attachment H provides a visual depiction of the area surrounding the mine and the vast land

owner opposition to this project.

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September 21, 2012

12

for public comment, as confirmed by ADEQ’s public notice, and despite our repeated

requests for formal public comment prior to permit issuance.

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13

2 This Is Not a Pilot But Instead Commercial Mining Phase 1.

A review of Curis’s application makes it apparent that its proposed Commercial

Production Test Facility (Commercial PTF) is not a pilot at all, but instead just the first

phase of commercial mining. According to Curis’s own submittals, both the expected

duration and the scope of the proposed operations exceed those of any true pilot

project. ADEQ’s regulation contemplates a temporary permit in two scenarios – first,

for a facility with a discharge lasting no more than six months and second, for a pilot

project to develop data for an APP application for the full-scale project.23 Curis’s

temporary permit application tries to depict itself as the second scenario. Curis claims

that it is necessary to operate the Commercial PTF to develop data for the full-scale APP

project application.24 This statement is made despite Curis’s previous repeated

assurances that they fully understand the area’s characteristics, the potential impacts of

the project and could adequately address any agency concerns and questions.25 They

also make this statement despite the fact that Curis’s proposed Commercial PTF does

not and cannot meet the criteria of a pilot project as defined in State regulation.

According to ADEQ’s own regulations, ‚pilot project‛ is a defined term,

meaning ‚a short-term, limited-scale test designed to gain information regarding site

conditions, project feasibility, or application of a new technology.‛26 The defined

duration of a temporary permit, one year with a potential one year renewal,27 provides

context to what is considered ‚short-term‛. If the permit can only last one year,

23 Ariz. Admin. Code § R18-9-A210.

24 Temporary Application at § 9.2.

25 Florence Reminder and Blade Tribune, Curis: Developers know or should have known about copper

project (April 14, 2011) (‚In-situ recovery . . . technology is proven, and was successfully

demonstrated in Florence a decade ago during a production test undertaken by previous owner

BHP. . . . Curis is very confident that its operations will not affect community water resources . .

.‛); Id., Curis fields water questions from open house attendees (June 30, 2011) (‚This technology is

safe, it’s proven, and it’s been used for decades around the world. . . . A study was done here

that shows this project works, the technology works. . .‛). 26Ariz. Admin. Code. § R18-9-101(30).

27Ariz. Admin. Code. § R18-9-A210(E).

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September 21, 2012

14

potentially two years at the very most, then ‚short-term‛ must be something within the

confines of one to two years.

Incredibly, Curis proposes a 12-year project, ten years longer than the possible

permit duration, as a short-term pilot project. Although Curis represents within its

application that its Commercial PTF will involve two years of leaching and rinsing,28

this 2-year period fails to include post-closure monitoring. Indeed other sections of

Curis’s application clarify that they propose a 5-year post-closure monitoring period29

which when added to two years of leaching/rinsing bring the total life to seven years.

But the Commercial PTF's life-span does not stop there. Instead Curis further

represents that post-closure monitoring may be extended another five years30 which,

when added to the 7-year life, brings the total to twelve years,31 a duration far longer

than the outer 2-year limit of a temporary permit.

A review of other projects for which temporary permits have been sought,

reveals that short-term pilot projects as envisioned by ADEQ’s rule have projected

durations shorter than the one-year initial permit term. In stark contrast to Curis’s

proposed 12-year Commercial PTF, is the El Paso Natural Gas Copper Eagle Gas

Storage Project which sought a temporary permit for a one-time brine injection.

According to the application, the proposed El Paso Pilot Project consisted of a 60-day

hydrogeologic test followed by a 120-day reservoir pressure falloff monitoring period, a

total duration of 180 days32 – a period well within the one-year regulatory permit

duration. Similarly, an application associated with the Blue Beacon Truck Wash in Eloy

proposed an experimental wetland with a mere six-month proposed life.33 Not only

28 Temporary Application at § 2.2 and Exhibit 9A, § 7.0; see APP Form, Section 11.

29Temporary Application at §§ 5.4.2, 16.3.2.

30 Temporary Application at § 16.3.2.

31 This potential 12-year project is also questionable in light of the fact that Curis leases the land

from the State which is currently set to expire in December 2013.

32 Arcadis, El Paso Hydrogeologic Test, Final Temporary Aquifer Protection Permit Application

(August 19, 2004).

33 See Blue Beacon Truck Wash Temporary APP Application (January 26, 2001); see also Blue

Beacon Truck Wash Notice of Intent to Construct an Experimental Wetland (December 20,

2000).

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September 21, 2012

15

does Curis’s proposed Commercial PTF fail to meet the common-sense meaning of

‚short-term‛ but it also flies in the face of project durations previously considered by

the agency under the temporary permit regulation. Curis’s proposed 12-year project,

six times the maximum permit duration, simply does not qualify as a pilot project

under the temporary permit regulation and should be denied by ADEQ.

ADEQ has also in the past, required a similar project to first obtain its UIC

permit from the USEPA before proceeding with the project’s temporary permit

application. According to the public records associated with the El Paso Natural Gas

Copper Eagle Gas Storage Project, the project proponent first argued that a UIC permit

was unnecessary, an argument that ADEQ did not buy into. Not only did ADEQ

require the project proponent to seek a UIC permit, but the agency went a step further,

issuing a deficiency letter and requiring the project to first obtain its UIC permit before

the temporary permit application would be reviewed any further. We question how

Curis’s proposed project is any different and why ADEQ would choose to treat Curis

any differently than the project proponent in El Paso Natural Gas. ADEQ should treat

Curis’s failure to obtain a UIC permit as a deficiency and deem Curis’s application

incomplete until it secures the necessary UIC permit from the USEPA.

Nor does the scope of Curis’s proposed Commercial PTF fit the purpose and

intent of the temporary permit process. It is not designed to provide information

needed to complete the full APP application nor is it designed to answer the agency’s

questions about Curis’s ability to safely protect groundwater and the environment from

the acidic solution.

Curis defines its purported Commercial PTF as ‚*a+ pilot-scale facility proposed

to be located on State land within the FCP site for the evaluation of ISCR processes,

including the potential for producing Grade A copper cathodes.‛34 Among Curis’s

purported purpose for this Commercial PTF is to develop data for the pending APP

amendment application for Phase 2 commercial operations. Additional proffered

justifications are to develop data to confirm hydraulic control and solution

characteristics, for water treatment and management options, and for design elements. 35

34 Temporary Application at xviii.

35 Temporary Application at Attachment 2, page 2.

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September 21, 2012

16

Despite these assertions, Curis plans to secure its commercial operation permits

before finalizing and evaluating the Commercial PTF data. ADEQ is well aware of

Curis’s plans. The agency has publicly stated that it intends to issue the commercial

permit without the benefit of the pilot data and indeed that the data is unnecessary for

commercial permit issuance. If the commercial permit will be processed without the

benefit of the Commercial PTF data, how can the Commercial PTF develop data for the

Phase 2 commercial permit? And how can the Commercial PTF be ‚a short-term,

limited-scale test designed to gain information regarding site conditions, project

feasibility, or application of a new technology‛ as required by the temporary permit

regulation? The only answer is that Curis’s proposed Commercial PTF is not a pilot test

at all. Instead it is the first phase of commercial production contrary to the temporary

permit regulations and the existing permit and all without the benefit of a full agency

review accompanied by public notice and comment.

The proposed construction of an SX/EW plant merely to process the extracted

copper from the Pilot is another example of how the Commercial PTF is just the first

step in commercial mining. Previously Curis represented that it would use a

temporary, portable solvent extraction/electrowinning (SX/EW) plant in its Phase I pilot.

But now, for this supposed limited scale Commercial PTF, Curis proposes to construct a

permanent SX/EW plant capable of full-scale commercial production. Furthermore,

Curis plans to produce one million pounds of copper plate during this ‚pilot.‛36 Such

large-scale commercial production goes far beyond legitimate hydrogeological

investigation. Again, this calls into question whether the true intent of the project is to

further protection of the aquifer or to further Curis’s business and financial interests

while trying to avoid a significant permit amendment.

When ADEQ released the prior project proponent from its financial assurance

obligations through an ‚Other Amendment,‛ it forbade Curis from engaging in

36 Proactiveinvestors Audio Interview with Michael McPhie (February 2012),

http://www.youtube.com/watch?v=v2FaxdqXrnQ (visited on April 30, 2012).

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September 21, 2012

17

commercial operations prior to securing a significant permit amendment.37 We suspect

one of the reasons behind the ADEQ-imposed condition was to ensure thorough public

participation prior to any permitting decision regarding the mine. But even with this

explicit admonition, Curis plans to engage in commercial production as part of its

Commercial PTF. According to Curis the Commercial PTF includes a ‚solvent

extraction/electrowinning (SXEW) processing plant that will produce copper cathodes

for commercial use.‛38 By Curis’s own admission, its Commercial PTF will engage in

commercial activities in direct contradiction to the terms of its existing permit. A

temporary permit for Curis’s Commercial PTF is not only inappropriate and

inconsistent with regulatory authorities but is also contrary to the existing permit.

Curis’s application is nothing more than an attempt to game the APP process to

the company’s advantage. Curis’s Commercial PTF is already a component of the

company’s pending application, albeit in a different location. Curis should have

amended its application for a significant permit amendment to reflect the ‚Pilot’s‛

changed location and new facilities. The only advantage to filing a new application

under a temporary permit program ill-suited to Curis’s project is that Curis could avoid

public comment under the temporary permit process until after the permit has already

been issued. Curis desperately wants a win to impress shareholders and the media and

is hoping the temporary permit will provide that win. ADEQ should reject Curis’s

attempt to side-step the normal permitting process and avoid public scrutiny of the

Commercial PTF. Instead, ADEQ should deny Curis’s application for a temporary

permit and require Curis to obtain a significant amendment prior to commercial

operations.

37 See Curis Resources (Arizona) Inc., Application to Amend Aquifer Protection Permit No.

101704 (Nov. 18, 2010), (Application to Amend) Attachment 1 at 4; ADEQ Notice of Granting

License (June 9, 2011).

38 Curis’s Response to ADEQ’s May Deficiency Letter, Attachment 20 (M3 Runoff Pond Design

Report) (emphasis added).

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September 21, 2012

18

3 Best Available Design and Control Technology—Injection

Well Field

Curis’s application purports to document compliance with the individual

BADCT requirements applicable to the Commercial Production Test Facility’s injection

well field. Arizona law requires that the well field ‚be so designed, constructed and

operated as to ensure the greatest degree of discharge reduction achievable through

application of the best available demonstrated control technology, processes, operating

methods or other alternatives, including, where practicable, a technology permitting no

discharge of pollutants.‛39 Appropriate BADCT measures are determined through

consideration of, among other things, ‚site specific hydrologic and geologic

characteristics and other environmental factors.‛40 BADCT measures must be described

in the Temporary APP application.41 To assist in determining appropriate BADCT for a

facility, ADEQ has published procedures and guidance in its Arizona Mining Guidance

Manual BADCT.42

Curis’s individual BADCT demonstration for the Commercial PTF well field is

deficient and should not be relied upon by ADEQ. Instead of immediately issuing a

permit, ADEQ should require Curis to conduct additional analyses and submit to

ADEQ a revised BADCT description fully meeting the agency’s requirements. ADEQ

should then scrutinize that submittal and require Curis to answer any agency questions

before making a decision on Curis’s application.

3.1 Curis Cannot Satisfy ADEQ’s BADCT Requirements for Injection

Wells Because it Proposes to Inject Acidic Mining Solutions

Directly Into a Drinking Water Aquifer.

The BADCT standard applicable to injection wells is simple. ‚Under no

circumstances, shall any new deep injection wells <be constructed to allow the

39 Ariz. Rev. Stat. § 49-243(B)(1).

40 Id.

41 Ariz. Admin. Code § R18-9-A202(A)(5).

42 Pub. No. TB 04-01 (ADEQ BADCT Manual).

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September 21, 2012

19

migration of fluids into or between underground sources of drinking water.‛43

USEPA’s outdated aquifer exemption notwithstanding, Curis proposes to do just what

BADCT prohibits—directly inject acid mining solutions into an underground source of

drinking water.

ADEQ appears to have ignored this overriding prohibition in its own mining

manual. ISL injection wells have been used at other Arizona mines, such as San Manuel

Mine, where injected solutions were collected in recovery wells or underground mine

workings.44 But at San Manuel, fluids were not being injected into a source of drinking

water—no one intends to drink the water beneath a decades-old open pit and

subsurface copper mine. Therefore, injection wells at San Manuel do not violate the

BADCT prohibition.

Unlike San Manuel, Curis’s mine site sits above a major drinking water source—

the Lower Basin Fill Unit—that is both a current and future source of drinking water for

the residents of Florence. Any injection of acidic mining solutions in this area violates

the BADCT prohibition. This may not have been the case when the original APP permit

was issued to BHP in 1997. But this mine no longer sits alone in the middle of

thousands of acres of open desert. In its review of Curis’s application, ADEQ has

consistently ignored current conditions and current uses of the aquifer beneath Curis’s

mine. Permitting Curis to install injection wells into the Lower Basin Fill Unit is a direct

violation of ADEQ’s BADCT manual and ADEQ’s duty to protect drinking water

resources.

Nothing in Curis’s proposal serves to eliminate or mitigate this violation of

BADCT standards. Where injection is not directly into a drinking water aquifer,

BADCT recognizes numerous options for preventing ‚the migration of fluids into or

between underground sources of drinking water.‛ Discharge control measures may

include: (1) pumping to create a cone of depression in the aquifer that contains and

captures leaching solutions; (2) plugging and abandoning boreholes and wells so as to

prevent their use as a conduit for leach solution to contaminate drinking water aquifers;

43 ADEQ BADCT Manual at 3-46.

44 Norman Carlson, Kenneth Zonge, George Rin and Martin Rex, Fluid Flow Mapping at a Copper

Leaching Operation in Arizona (July 2000).

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September 21, 2012

20

(3) proper injection and recovery well design, construction, and operation; and (4)

passive containment such as slurry cut-off walls, hydrologic sinks, or other natural or

engineered control measures that do not need ongoing maintenance.45 Curis proposes

to use the first three of these options, but none of them changes the fact that Curis will

be injecting acidic mining solutions into a drinking water aquifer. Even if that were not

the case, Curis’s proposals for implementing these three options fall well short of

effective methods to control the flow of contaminated mining solutions and protect the

drinking water supply from toxic pollutants. For this reason alone, Curis’s application

should be denied.

3.1.1 The LBFU is a major drinking water supply for the Town of Florence.

There is no argument that, in the ‚vicinity surrounding the proposed in-situ

mine area, the LBFU is the principal source of groundwater withdrawals.‛46

Downgradient of Curis’s proposed mine are existing drinking water wells that pull

their water from the LBFU. Johnson Utilities’ nearest drinking water production well

(ADWR No. 55-212512) is just over a mile from Curis’s proposed mining operation.

Initially installed in October 2006, Johnson’s well is drilled to 597 feet, pulls water from

the LBFU, and has demonstrated excellent water quality meeting all drinking water

standards. This well is not yet connected to Johnson’s drinking water system, but is

clearly a foreseeable future use that must be protected.

Other foreseeable future uses include a 355-foot Southwest Value Partners

irrigation well and other irrigation wells that could eventually be converted into

drinking water wells when further development begins. To the extent these irrigation

wells could not be converted to drinking water uses for legal or other reasons,

numerous additional wells will be needed in the area in the foreseeable future.

45 Arizona BADCT Manual at 3-46.

46 Brown and Caldwell, Site Characterization Report, Volume II of V, at 3-16, § 3.6 (January

1996).

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September 21, 2012

21

Figure 1, Production Well Map

Future Town of Florence drinking water wells proposed to serve the Merrill

Ranch Master Planned Community are planned to be installed within the LBFU as close

as 1,500 feet from Curis’s proposed mine. Indeed development of future water

resources are part of the Town of Florence’s Designation of Assured Water Supply

currently under review by the Arizona Department of Water Resources. It is imperative

that ADEQ recognize the importance of this aquifer and its current and foreseeable use

as a future drinking water supply. As shown in the figure below, depth to bedrock is

SWVP-017747



September 21, 2012

22

deepest (750 to 1,000 feet bls) in the area located immediately downgradient of Curis’s

proposed mine. The best water quality and production potential is typically found

within the LBFU for development of drinking water production wells. Consistent with

industry practice, this area of deep depth to bedrock represents the area in which future

drinking water wells to serve residential demands are planned for installation. Red dots

in the figure below illustrate the seven future drinking water wells proposed in 2005 as

part of the Merrill Ranch Master Planned Community.

Figure 2, Revised Florence Pinal Model Depth to Bedrock vs. ADWR Pinal Model

Depth to Bedrock

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September 21, 2012

23

The cross-section below demonstrates the depth of these proposed wells in

comparison to Curis’s proposed injection zone within the ore body. All of the existing

and proposed drinking water production wells will penetrate and produce

groundwater from the LBFU, which is located directly adjacent to the ore body. As

depicted in the illustration above, the MFGU does not protect the LBFU and

contamination of the LBFU could easily migrate to vicinity wells and the regional

drinking water aquifer.

Figure 3, East/West Cross-Section Curis Arizona Property

3.1.2 The Middle Fine Grained Unit does nothing to protect the drinking

water aquifer.

Discharge controls should be designed to effectively control and contain the acid

mining solution and must account for site-specific factors such as surface hydrology,

hydrologic isolation, climate, facility location and the known physical and chemical

properties of in-situ leach material. According to ADEQ, geologic features can be used

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September 21, 2012

24

as effective subsurface containment. The burden, however, is on the applicant to

demonstrate performance of these site specific characteristics.47 Throughout the

application, Curis advocates that the Middle Fine Grained Unit (MFGU) is a natural

aquitard that protects area groundwater from the acid mining solution that Curis plans

to inject.

In actuality, the MFGU does nothing to protect Florence’s drinking water supply.

The MFGU is essentially a thin layer of clay located across portions of the mine site.

Where it exists at all, the MFGU is located between the Upper and Lower Basin Fill

Units. Although the UBFU is used for agricultural irrigation, it is not generally used for

drinking water due, in part, to the presence of relatively high concentrations of nitrates.

Current and future Florence-area drinking water wells produce water from the LBFU,

which is located below the MFGU and directly adjacent to the oxide zone into which

acid mining solutions will be injected, as seen in Figure XX. Therefore, the MFGU does

nothing to protect the LBFU and Florence’s drinking water supply from acid mining

solutions.

Figure 4, Block Diagram of Typical PTF Wells48

47 ADEQ BADCT Manual at 3-45 to 3-46.

48 Daniel Johnson Letter to Richard Mendolia, Attachment 7 (May 23, 2012).

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September 21, 2012

25

Furthermore, groundwater can move between the ore body and the UBFU.

Although the MFGU slows water flow, it is not impermeable and does not prevent

groundwater movement between the units. Curis’s arguments to the contrary directly

conflict with the Magma Copper reports on which Curis relies for its hydrogeological

evaluation:

[t]he LBFU is the principal source of groundwater beneath the Site.

The groundwater elevations and testing data generated from the

wells in the mine block area at the Site indicate that the presence

of the MFGU does not exert significant control on the circulation

of water between the UBFU and the LBFU. The hydrologic

characteristics measured at the site reflect conditions that are

comparable to a relatively unconfined aquifer with significant

connection into the bedrock intervals where mine block wells are

constructed.49

3.1.3 Curis proposes to inject acid mining solutions into a highly fractured

ore body.

What purportedly makes Curis’s proposed mine feasible (i.e., injection into and

recovery from a ‚highly fractured‛ ore body) is also what makes this project risky. The

following statement by Mr. Dan Johnson, P.E., Curis Manager of Environment and

Technical Services at the Florence project illustrates this point.

The high frequency of prolific fracture patterns and densities

observed during the most recent drilling program further confirm

that the Florence copper oxide deposit represents the ideal

conditions for in-situ recovery of copper. The porous nature of the

deposit creates significant hydraulic communication both laterally

49 Brown and Caldwell, Volume II of V, Site Characterization Report, January 1996 (emphasis

added).

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September 21, 2012

26

and vertically across geologic structures and rock types throughout

the oxide deposit.50

ADEQ’s BADCT guidance states that ‚*h+ydrologeology and structural geology (e.g.,

subsidence zones, slope failure, faults, etc.) within the ore body and surrounding area

are usually of key importance to solution control at in-situ mining facilities.‛51 As a

result, Curis is required to evaluate geologic hazards up to one-half mile or more

outside the facility’s perimeter and then account for the findings within their BADCT

design.52

Although the highly fractured nature of the ore body makes it conducive to in-

situ leaching, it also makes movement of injected acidic solution and groundwater

unpredictable and difficult to control. Fractures can short-circuit anticipated solution

migration pathways, allowing injected acidic solution to travel to unanticipated and

unintended areas underground, potentially including drinking water aquifers. 53 If

Curis loses control over the injected acidic solution, the ‚porous nature of the deposit‛

may allow the solution to migrate laterally with the potential to impact the adjacent


In its Temporary APP application, Curis claims that fractures and faults will

actually enhance the cone of depression created by its recovery wells, thereby

decreasing the chance of excursions.54 Such an affect may be seen in some areas, but it is

equally likely that variations in hydraulic conductivity caused by faults and fractures

will significantly increase the chance that mining pollutants will escape Curis’s control.

For instance, if the hydraulic conductivity in the area of injection is low, mounding of

injected fluids could occur. Subsequently, if the hydraulic conductivity in the area of

the recovery wells is high, it would most likely require significant pumping at the

recovery wells to affect a water level that would be lower than that of the associated

50 Curis Resources, LTD news release, Florence Copper Project Advances Towards Development (July

20, 2011).

51 ADEQ BADCT Manual at 3-40 (§ 3.4.4).

52 ADEQ BADCT Manual, Section 1.2.4 and at 3-42.

53 ADEQ BADCT Manual at 3-40 to 3-41.

54 Temporary Application at §§ 14C.4.2 and 14C.4.3.

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September 21, 2012

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observation well. Although Curis indicates that it will, if necessary, tighten well

spacing in areas of ‚increased hydraulic conductivity,‛ Curis provides no details and

makes no firm commitments in this regard.55

Nor does Curis have an adequate understanding of this fractured ore body. For

instance, in discussing the injection pressure projections, Curis cites to the 1995 BHP

analysis supporting a minimum fracture gradient of approximately 0.71 psi/ft for rock

within the oxide zone and the establishment of a 0.65 psi/ft fracture gradient limit.56

Curis has not updated and does not even plan to update the fracture analysis upon

which these calculations are based, relying instead data and analysis that is 17 years

old. Curis is attempting to skate by with a ‚one size fits all‛ approach to the control

and recovery of acidic mining solutions and contaminants within a complex and highly

fractured system.

3.1.3.1 BHP acknowledged that it did not adequately understand this

system.

After its 1998 pilot test, BHP itself recommended that new field tests were

necessary to prove the viability of ISL mining at this site. BHP recommended that this

second round of testing be conducted for a much longer period than BHP’s first 90-day

pilot test and that it use a multiple-cell test field and an expanded water management

system. But to design an appropriate second pilot test, BHP recommended that an

‚improved understanding of the geochemical and hydrogeological mechanisms at

work‛ was needed.57 In other words, BHP recommended that the types of investigation

we are describing should be conducted before any subsequent pilot testing was

attempted. Curis has done no such work.

As discussed more thoroughly in Section 3.1.3.2 below, site characterization is

needed to positively identify vein deposits and potential fractures and faults that could

55 Temporary Application at 14C.4.3

56 Curis’s Response to ADEQ’s May Deficiency Letter at Response to comment 13.

57 Letter from Roger Ames, Registered Geologist, Merrill Mining, to Bryan Wilson, President

and CEO, Mohave Resources, Inc., at 3 (November 21, 2006) (citing BHP’s Draft Field Test

Report, at 102 and 110-111).

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September 21, 2012

28

provide escape routes for mining solutions. Common methods that Curis could use to

characterize the deposit and fracture systems include hydraulic testing, hydrophysical

flow logging, osmotic transport monitoring cells, and geophysical characterization of in

situ fracturing. After such characterization is completed, Curis should conduct a small

pilot scale study on a few wells in the study area using a test liquid such as fluorescent

dye. The dye would be injected into one well to determine how much of the fluid could

be recovered in other wells. Only through such investigation and analysis can an

appropriate injection and recovery well system be designed for the Commercial PTF site

to ensure capture of injected mining solutions. Insert footnote: See Golder Associates

Inc., Hydraulic Tests at the Florence Mine Site for Magma Copper Company Florence In Situ

Leaching Project (February 1996) (‚Golder Report‛).

3.1.3.2 USEPA is concerned that Curis does not adequately

understand fractures and faulting in the Commercial PTF area.

EPA has noted a number of modeling inadequacies in Curis’s UIC application

materials, some of which are directly related to the occurrence of fractures and faults

within the project area.58 For instance, USEPA’s Comment 17 noted Curis’s failure to

accurately model fluid movement in the oxide bedrock zone, taking into account lateral

variation posed by faults and fractures. The EPA comment indicated that Curis was

using constant porosities and hydraulic conductivity values in the five layers of the

oxide bedrock zone. Curis’s UIC groundwater model simulates a single resource block,

so the scale of the model does not encompass the large-scale fractures. Curis defends its

use of constant aquifer parameters for the oxide bedrock model layers by stating that

the small-scale fractures are simulated using an equivalent porous media (EPM)

assumption supported by the Golder Report’s aquifer test analysis documentation,

among other sources.

Use of the EPM assumption requires consideration of the scale of the important

processes being simulated in the model. Golder stated that ‚simulation of flow with a

code such as Modflow is appropriate at the scale of the proposed in-situ leaching area,‛

58 David Albright Letter to Michael McPhie (January 30, 2012).

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suggesting that the EPM assumption is appropriate for simulating flow through a 3,600

by 3,300 foot area.59 However, further analysis is necessary to evaluate whether the

EPM assumption is appropriate for mining-block scale flow and contaminant transport,

the scale of modeling necessary to simulate the recovery of injected lixiviant within one

of Curis’s resource blocks. That analysis should include:

Analysis of observations made during and after the BHP pilot test, including

changes in contaminant concentrations measured in the test block wells.

Discrete fracture network modeling to characterize the deposit and fracture

systems including hydraulic testing, hydrophysical flow logging, osmotic

transport monitoring cells, and geophysical characterization of in situ

fracturing.

Pilot testing using a fluorescent dye tracer to determine the recovery of

injected fluids from discrete zones of the aquifer.

Following these analyses, conceptual flow models, including the EPM assumption,

should be evaluated for simulating contaminant flow and transport within a resource

block. The UIC Model should be adjusted accordingly and calibrated to observations

made during the BHP pilot test and the tracer tests.

Curis states that Golder concluded that the large scale fractures ‚are of greater

significance than small-scale heterogeneity and anisotropy.‛60 However, even at the

sub-regional scale of the FCP Model, small-scale heterogeneity and anisotropy may still

be significant, even if to a lesser degree than the heterogeneity and anisotropy caused

by the large-scale fractures. As discussed above, small-scale features may be significant

when modeling flow between wells within a mine resource block.

USEPA’s Comment 19 also reflects EPA’s concerns regarding the increased

conductivity created by fault zones and associated fracture networks and Curis’s failure

59

Golder Associates Inc., Analytical Interpretation of Hydraulic Tests at the Florence Mine Site for

Magma Copper Company Florence In Situ Leaching Project (February 1996). 60 Curis Response to EPA RFI (March 30, 2012) at Comment 17.

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to model the worst case scenario accounting for fault conductivity of 40 feet per day

over a 3,000 foot length.61 Curis’s response to the EPA indicated that the 40 feet per day

value was anomalous and that ‚additional verification and analysis *is needed+ to

identify the cause of this anomalously high conductivity estimate.‛62 It does not appear

that additional verification and analysis have been conducted to date that adequately

address this issue.

USEPA’s concerns are supported by other authorities in the area. One recent

authority has indicated that, in highly fractured ore bodies, ‚careful site

characterization is needed to positively identify vein deposits to be produced, and

potential fractures and faults that could provide escape routes for lixiviant.‛63 Discrete

fracture network modeling is necessary to characterize the deposit and fracture systems,

including hydraulic testing, hydrophysical flow logging, osmotic transport monitoring

cells, and geophysical characterization of in situ fracturing. Following completion of

the work identified above, the article recommends that a small pilot scale study be

completed on a few wells in the study area where a test liquid (fluorescent dye) would

be injected into one well to determine how much of the fluid could be recovered in

other wells. The author notes that ‚In fractured rock, hydraulic cage performance can

potentially be degraded where discrete fractures bypass the head control and

monitoring well.‛64 The last point highlights a significant concern with this project—if a

discrete fracture network is present that potentially bypasses Curis’s hydraulic head

control, the resultant loss of contaminated mining solutions would not be detected by

the observation monitoring that Curis has proposed.

3.1.3.3 Evidence exists that hydraulic control may have been lost

during the BHP pilot due to fracturing in the pilot test area.

The variability inherent in this fractured system may have been responsible for

the loss of hydraulic control noted in the BHP Pilot Test between the

61 EPA Request for Information (January 30, 2012).

62 Curis Response to EPA RFI (March 30, 2012) at Comment 19.

63 Bill Dershowitz, Discrete fracture network modeling in support of in situ leach mining (Mining

Engineering Magazine November 2011).

64 Id.

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recovery/observation well pair (BHP5/OWB4) at which hydraulic control was not

adequately maintained over a 2 to 3 day period with a gradient differential (flow in the

wrong direction) documented during a 12-hour period that was greater than 48 feet.

Also, it appears that hydraulic control was only marginally maintained at this location

with a relatively flat groundwater gradient documented from November 8, 1997 to

November 18, 1997.

A ground water elevation increase of almost 200 feet occurred in recovery well

BHP5 during the start-up of the pilot test on November 8, 1997. No explanation was

provided in the BHP report documenting the pilot test. However, it can be assumed

that there was either a malfunction in the pumping mechanisms of the recovery well

(BHP5), or that significant mounding may have been occurring between the paired

injection well (BHP9) and Recovery well BHP5. Curis has never addressed this data

and ADEQ has not required Curis to evaluate the data and conduct additional

investigation.

3.1.4 Loss of hydraulic control could allow acidic solution to migrate

from the ore body into both the LBFU and UBFU.

Because this is a highly fractured ore body and because that ore body is in direct

communication with the LBFU, a high risk of drinking water contamination in the

LBFU exists. As illustrated in Figures 3 and 4, above, drinking water in the LBFU flows

above and beside the copper ore body. Curis’s cross-sectional diagram, reproduced in

Figure 5 below, shows that the ore body drops off precipitously along the western

portion of Curis’s property, directly under the Commercial PTF well field. If acidic

solution escapes Curis’s control, it is a short distance through the oxide ore body to the


There is no argument refuting that water flows through the oxide ore body into

the drinking water aquifer. The BHP studies that Curis relies upon in support of the

Temporary APP made clear that the ore body and the LBFU are in hydraulic

communication:

The maximum difference in head between the vertical gradient

contours between the LBFU and the bedrock oxide zone is plus or

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minus 2 feet. These observations are interpreted to mean that the

LBFU and bedrock zone are in hydraulic communication.65

Figure 5, East-West Cross-Section of Commercial PTF

Therefore, absent hydraulic control, acid mining solutions injected into the ore body

will find their way into the drinking water aquifer. Neither the MFGU nor any other

geologic barrier will prevent the pollution of Florence’s drinking water. Florence and

65 Brown and Caldwell, Site Characterization Report, Volume II of V, at 4-18, § 4.3.3.6 (January

1996) (emphasis added).

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its residents will be completely dependent upon the success of hydraulic control

measures that, to date, have been proven to work at this site only in theory.

This does not even take into consideration the fact that the ore body is also filled

with anthropogenic subsurface conduits, all of which provide potential pathways for

groundwater movement. As explained in more detail within these comments, the

property has been the site of historic mineral exploration activities resulting in

numerous core holes, mine shafts, and wells, many of which will be nearly impossible

to locate and properly abandon. The combination of a naturally-fractured ore body

along with these man-made conduits creates an incredibly challenging environment for

the maintenance of hydraulic control. Curis has not demonstrated that it is up to the

challenge of maintaining hydraulic control under these conditions.

3.2 Curis’s Well Field Design Has Not Been Shown to Prevent Acid

Mining Solutions from Polluting the Drinking Water Supply.

BADCT requires Curis to employ effective discharge control measures that will

prevent the contamination of Florence’s drinking water supply by Curis’s mining

solutions. Relevant to Curis’s proposal, these measures include not injecting acid

mining chemicals into the drinking water aquifer; sufficient pumping to create a cone of

depression in the aquifer that will uniformly and continuously contain mining

contaminants within the Commercial PTF area; proper injection and recovery well

design, construction, and operation; and proper plugging and abandoning of old

coreholes and wells to eliminate them as preferential pathways for mining

contaminants.66 Curis has failed to demonstrate that any of these control measures will

be met during Commercial PTF operations.

3.2.1 Curis does not propose to demonstrate that it can maintain

hydraulic control during Commercial PTF operations.

As discussed elsewhere,67 BHP’s pilot test was a 90-day test employing a handful

of injection and recovery wells that was terminated early. BHP did not even bother to


67 Section 6.0

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34

submit a final report on the test to ADEQ or USEPA before abandoning the Florence

Copper Project altogether. Although BHP and its successors have touted limited data

from the pilot as evidence that hydraulic control was maintained, the test clearly has

limited, if any relevance to Curis’s proposals and is not sufficient to show that Curis can

maintain hydraulic control of acid mining solutions during full scale commercial

production.

Further demonstrating that it values profits over environmental compliance,

Curis did not even propose to demonstrate hydraulic control as a component of

Commercial PTF operations. As evidenced by its submission to USEPA, Curis believes

that no demonstration of hydraulic control is necessary because the ‚capacity to inject

and recover ISCR solutions was demonstrated and documented by BHP Copper in

1998.‛68 USEPA has rejected Curis’s position and will require a demonstration of

hydraulic control as part of the Commercial PTF results.69 ADEQ similarly should

require Curis to demonstrate that it is able to maintain hydraulic control over mining

contaminants using a well field design that replicates commercial mining operations.

3.2.2 Curis’s Commercial PTF well field design differs significantly from

the design proposed for commercial production.

For commercial production, Curis describes the well array in a typical mine

block unit as follows:

Operational units will be ringed by perimeter wells (designed and

constructed the same as Class III wells), the purpose of which is to

maintain hydraulic control. The number of perimeter wells will

depend on the size and shape of the operational unit. By using perimeter

wells to maintain hydraulic control, the flow of PLS pumped from the

operational unit can equal the flow of raffinate (lixiviant) injected into the

unit . . . .70

68 Daniel Johnson Letter to Nancy Rumrill, at vii (June 1, 2012).

69 USEPA, Request for Information, at 3 (July 20, 2012).

70 Daniel Johnson Letter to Nancy Rumrill, at 7 (March 30, 2012).

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35

Thus, hydraulic control during commercial production will purportedly be maintained

at the edges of a mine block unit. The resulting well field will be arranged as depicted

in Figure 6, below.

Figure 6, Conceptual Well Field Array71

BHP did not use perimeter wells in its pilot test and Curis is not using perimeter

wells in the Commercial PTF well field.72 Instead, Curis proposes to maintain hydraulic

control by pumping more from the Commercial PTF recovery wells than it injects.

Given this obvious and significant difference between well field designs, any purported

demonstration of hydraulic control produced by the Commercial PTF will be irrelevant

to a demonstration that Curis’s proposal for commercial production will work.

71 Figure 1 from Daniel Johnson Letter to Nancy Rumrill (March 30, 2012).

72 Daniel Johnson Letter to Nancy Rumrill, at vi (June 1, 2012).

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The lack of perimeter wells in the Commercial PTF well field design is not

obviated by Curis’s proposal to monitor water levels in pairs of Commercial PTF

recovery and observation wells.73 During commercial production, injection and

recovery wells will not generate a hydraulic gradient because recovery will match

injection rates.74 Perimeter wells will be located hundreds of feet from interior injection

and recovery wells within a given mine block. That distance provides numerous

possibilities for acid mining solutions to intersect preferential pathways and escape

Curis’s control before encountering the hydraulic gradient created by the perimeter

well field. The same conditions are not replicated by a Commercial PTF well field that

places observation and recovery wells with 75 to 100 feet of one another.

Curis’s Commercial PTF proposal will, at best, generate data regarding hydraulic

capture from a well field that will never see commercial production. ADEQ should

require Curis to demonstrate that its perimeter well field design will work with real-

world data.

3.2.3 Curis fails to demonstrate that the 40-foot exclusion zone will

protect the drinking water supply and fails to account for the site

specific geology present in the steep interface between the LBFU and

oxide units.

Curis has proposed to begin injection no less than 40 feet from the top of the

oxide ore body.75 Purportedly, this 40-foot ‚exclusion zone‛ will form a buffer between

the ore body and the surrounding LBFU to help prevent the migration of acid mining

solutions into the drinking water supply. Contrary to Curis’s assertions, the 40-foot

exclusion zone will not protect groundwater at all times. It is an incomplete solution to

an overly simplified model of the geology beneath the mine site.

One of the hydrogeologic peculiarities associated with the Commercial PTF well

field is its proximity to a steep vertical fall-off of the oxide ore body. On the western


74 Daniel Johnson Letter to Nancy Rumrill, at 7-8 and 14-15 (March 30, 2012).

75 Temporary Application, Attachment 9 (Design Documents), at 4, § 9A.3.1.3 (May 1, 2012).

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portion of the property near where the Commercial PTF well field is located, the

interface between the ore body and adjoining drinking water aquifer is nearly vertical.

In this area, highlighted in Figure 7, a 40-foot exclusion zone in the injection well

column does absolutely nothing. There is no horizontal barrier between the injection

well and the LBFU that will prevent the flow of acid mining solutions into the drinking

water aquifer. Curis fails to account for this steep interface anywhere in the proposed

BADCT for the Commercial PTF well field.

Figure 7 Curis Property Bedrock Topography

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38

3.2.4 Curis’s placement of observation wells in the Commercial PTF well

field is designed to succeed but does not replicate commercial

production.

The Commercial PTF well field will have seven observation wells placed in

between the outer ring of four recovery wells. Four other recovery wells will be located

inside this outer ring, next to the observation wells.76 Because there will be no perimeter

wells, Curis proposes to monitor groundwater levels by comparing the water levels in

the observation wells to those in the recovery wells.77 Although it is doubtful that Curis

originally proposed to submit data demonstrating hydraulic control in the Commercial

PTF well field, we assume that data will be forthcoming given USEPA’s position that

hydraulic control has not been demonstrated.

Such data will compare water levels between eight recovery wells and seven

observation wells spaced less than 100 feet apart. We have no doubt that this data,

considered in a vacuum, will show that Curis has successfully maintained hydraulic

control. Even so, the data will be entirely irrelevant to proving that commercial ISL

mining is safe at this site.

Unlike the Commercial PTF well field, a commercial mine block will contain

hundreds of injection and recovery wells, but will actually contain fewer observation

wells. Referring back to Figure 6 above, Curis’s ‚hypothetical‛ well field array depicts

a mine block containing 602 wells—60 perimeter wells, 266 recovery wells, 271 injection

wells, and just five observation wells. Groundwater levels in those five observation wells

will be compared to levels in adjacent perimeter wells to monitor hydraulic gradients.

There will be no other monitoring wells within a mine block.78 Thus, assuming Figure 6

is a reasonable approximation of commercial production, Curis proposes to use just five

observation wells to monitor hydraulic control along a perimeter that is over a mile and

a half long.

76 Temporary Application at Attachment 12, Figure 12-1.



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39

Curis has proposed a Commercial PTF that is designed to succeed, but that has

nothing to do with commercial operations. This is further evidence that, for purposes of

proving environmental safety in support of an APP permit, Curis’s production test is a

sham.

3.2.5 Curis’s description of proposed methods for determining hydraulic

control cannot be used for the Commercial PTF.

Curis has to demonstrate, through objective data, that it is maintaining hydraulic

control of acid mining solutions from the first day of injection through mine closure.

But Curis has never clearly indicated how it will do so during Commercial PTF

operations. The discussion in the previous section assumes that Curis will demonstrate

hydraulic control through a comparison of groundwater levels in recovery and

observation wells. But because of Curis’s ever-changing proposals for this project, we

cannot be sure that our assumption is correct. If we are incorrect, then Curis has

proposed no other method for demonstrating hydraulic control that makes sense for the

limited well field proposed for the Commercial PTF.

In some places, Curis indicates that hydraulic control will be demonstrated by

comparing the ‚totalized flows from all the injection manifolds‛ to the ‚summed

totalized flows from all of the manifolds from recovery wells, hydraulic control (HC)

wells, and IRZ restoration wells.‛79 Elsewhere, Curis indicates that it will compare

‚well pairs‛ along the perimeter of a mine block and that hydraulic control will be

demonstrated ‚when the water level in the outer well is higher than the water level in

the inner well of each well pair.‛80 Of course, neither of these methods can be used

during Commercial PTF operations because Curis is not using perimeter (HC) wells

during Phase 1. Any recovery of contaminated mining solutions injected during

Commercial PTF operations will come solely from the recovery wells. The fact is,

Curis’s Temporary APP application describes a method of measuring hydraulic control

during commercial operations that cannot be used for the Commercial PTF.81 Instead,

79 Curis Arizona, UIC Application, Appendix 1 (Operations Plan) at 2 (revised April 25, 2012).

80 Id. at 3.

81 See generally, Temporary Application, Attachment 11 (BADCT Description) at 6, § 11.3.1.

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40

hydraulic control during Commercial PTF operations will be based upon a comparison

of water levels in four pairs of observation and recovery wells.82

Attempting to defend their hydraulic control methods, Curis touts its 7

observation wells and 4 ‚highly advanced multi-level sampling wells‛. They

characterize this number of wells designed to monitor conditions as ‚large‛ in

comparison to the 1997 pilot’s use of 5 observation and 2 multi-level sampling wells.83

But when questioned by ADEQ concerning their proposed methods regarding their

stated ability to conduct multi-port sampling in observation wells, Curis admitted that

the observation wells are only ‚for the purpose monitoring hydraulic control to ensure

that ISCR solutions are contained within the IRZ.‛84 They also indicated that the four

proposed multi-level sampling wells (Westbay wells) will be installed adjacent to the

central injection well and are ‚for the specific purpose of the monitoring the flow and

geochemical composition of ISCR solutions between the central recovery well and the

four injections wells‛ and ‚the information that they produce will have no relevance to

hydraulic control and will have no direct relevance to contemporaneous groundwater

quality at the IRZ perimeter.‛85 In other words, Curis will have no way to monitor

whether injected solutions are potentially migrating beyond the Commercial PTF well

field through discrete fracture patterns that may be present. Due to the distance of the

POC wells from the Commercial PTF site, it may take many years before any

contaminants lost from the process would be detected in those wells. Also, it may never

be detected if actual flow directions are not directly in line with the inadequately placed

POC wells.

3.2.6 Curis has not demonstrated that it can maintain hydraulic control to

overcome vertical groundwater gradients in the Commercial PTF.

A consistent downward vertical gradient exists between the UBFU, LBFU, and

Oxide Unit across the Commercial PTF area. Curis claims that BHP’s pilot test proved

82 Temporary Application, Attachment 2 (Facility Description), §§ 2.4.1 and 2.4.2 at 4-6; id.,

Attachment 9 (Design Documents), § 9.2 at 3.

Temporary Application, Attachment 11 (BADCT Description), § 11.10.5 at 16.

84 Curis Response to May Deficiency Letter, Response to Comment 4

85 Id.

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that hydraulic control could be maintained so as to overcome this gradient.86 In fact, as

USEPA has recognized, BHP’s pilot test did not demonstrate hydraulic control.

Therefore, Curis is mistaken in assuming that this downward vertical gradient can be

ignored.

Vertical groundwater gradient can transmit contaminants from one water-

bearing groundwater unit to another. Curis indicates that groundwater gradients at the

mine site range from a few inches to as much as twenty feet.87 These gradients can be

exacerbated by offsite irrigation or drinking water pumping; fluctuations in recharge

from the Gila River, Northside Canal, and agricultural irrigation; improperly sealed

core holes; preferential pathways such as fractures; and other factors. Curis cannot rely

on fifteen-year-old data from BHP as justification to ignore this issue. ADEQ should

require Curis to conduct adequate investigations at the Commercial PTF site to

demonstrate that it can overcome vertical hydraulic gradients as a condition to issuance

of an APP permit.

3.2.7 Curis’s well field design fails to account for known groundwater

mounding near the Commercial PTF well field.

Evidence exists of groundwater mounding in the LBFU and Bedrock Oxide Unit

of the Commercial PTF area. Curis theorizes that the mounding may be caused by

downward groundwater flow at wells completed across multiple water bearing units. 88

The mounding appears to have contributed to a minor western flow component in the

principal groundwater flow direction in the LBFU and Bedrock Oxide Unit.89

Unfortunately, despite evidence of groundwater mounding in this area, no

subsequent groundwater level data is available to confirm its scope and significance.

Although the issue was discovered as early as 1995, it was apparently ignored by BHP

86Temporary Application, Attachment 14C (Hydrologic Study-Supplemental Data), at 4 (March

1, 2012).

87 Id.

88 Temporary Application, Attachment 14C (Hydrologic Study-Supplemental Data), at 8-9, §

14C.2.6.2 (March 1, 2012).

89 Id.

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and neither USEPA nor ADEQ required additional investigation before issuing UIC and

APP permits in 1997. Since the permits were issued, no voluntary investigation has

been conducted by BHP or its predecessors. Although Curis acknowledges the issue, it

has not proposed to conduct additional investigation before it begins injecting acidic

mining solutions into this area, nor does it propose to study this issue as part of its

Commercial PTF operations. Instead, Curis glibly concludes, based on no evidence

whatsoever, that it can maintain hydraulic control in a manner sufficient to offset any

mounding issues in the Commercial PTF area.90

Variations in hydraulic conductivity will impact Curis’s ability to maintain

hydraulic control. Relevant here, if hydraulic conductivity in an area of injection is low,

mounding of injected fluids could occur. Such mounding effects may have been

responsible for the loss of hydraulic control noted in BHP’s pilot test between Recovery

Well BHP5 and Observation Well OWB4. Hydraulic control was lost at that location for

a period of at least 48 hours from November 8 to 10, 1997 and was sporadically

maintained over the next week.91 On the other hand, if hydraulic conductivity is high

within an extraction area, significant pumping from recovery wells could be required to

maintain hydraulic control where mounding has occurred.

This groundwater mounding issue is a clear example of a problem that has been

known but conveniently ignored by Curis and its predecessors for nearly twenty years.

It also highlights the fact that Curis lacks a clear understanding of hydrogeological

conditions in the Commercial PTF location, much less across the entire mine site.

Elsewhere, to avoid blame for excursions of pollutants, Curis has claimed that declining

groundwater levels have caused increased concentrations of various contaminants.92

Nowhere, however, has Curis attempted to reconcile this purported phenomenon with

evidence of groundwater mounding. Such discrepancies indicate that Curis lacks an

adequate understanding of a very complex hydrologic system at this site and undercuts

any assertion that hydraulic control can be maintained.

90 Id. at 9.

91 Temporary Application, Attachment 10, Appendix 10A-1 (BHP Letter to Ms. Julie Collins,

ADEQ (April 6, 1998)).

92 Temporary Application, Attachment 14B (Hydrologic Study Part B), at 5, § 14B.3.3 (March 1,

2012).

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43

3.2.8 Curis has not justified use of a five-spot well pattern.

ADEQ requested that Curis provide the technical basis for the Commercial PTF

well field design. Specifically, ADEQ requested a discussion of how natural and

induced fractures were determined in orienting the Commercial PTF wells, as well as a

discussion of other design specifications, such as acid solution pressure, flow rates,

pump specifications, etc.93 Curis never answered the question in a manner sufficient to

support its well field design and location.

Curis’s answer to ADEQ’s request first focuses on the purported suitability of its

selected five-spot pattern for injection and recovery wells. Curis mentions several

general forms of support for the five-spot well pattern proposed for the Commercial

PTF. For instance, Curis references the purported wealth of scientific study and

documentation supporting the five-spot pattern, but never bothers to cite specific

reports or documents. Curis cites the five-spot pattern’s use in the petroleum industry

for secondary recovery of petroleum by water-flood methods, an application that has

nothing to do with this project or the geology at this site. Curis mentions the five-spot

pattern’s wide application in the in-situ mineral recovery industry, without any

indication of why its use in uranium mining and other forms of mining in other states

justifies its application to copper ore in Florence. Curis also cites its use in the BHP Pilot

Test, a test that USEPA has already rejected for purposes of demonstrating hydraulic

control, a test that was terminated early, and a test for which final results have never

been publicly disclosed.94 Such references do nothing to justify why a five-spot pattern

is appropriate at this site.

We know from other documents for this project, however, that the five-spot

pattern is the cheapest well pattern Curis could use. A seven-spot pattern uses six

recovery wells instead of just four, but BHP vetoed the seven-spot pattern because ‚it

needs many more perimeter recovery wells than does a five-spot pattern, resulting in a

93 ADEQ, Comprehensive Request for Additional Information with Suspension, Item 13 (May 2,

2012).

94 Curis Response to May Deficiency Letter, Item 13.

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44

larger well construction cost.‛95 Curis also proposes to place the recovery wells one

hundred feet apart. Why? Because BHP’s calculations, which were based upon

injection rates and copper grades, suggest this is the maximum distance to achieve

optimal copper recovery rates. Closer spacing does not make economic sense because

‚*t+he larger the well spacing, the lower the drilling expenses will be.‛96 In the end,

‚*t+he spacing that generates profit‛—not the spacing that ensures hydraulic control or

is most protective of the environment—‚will be chosen as the optimal spacing.‛97 Thus,

Curis’s use of the five-spot pattern has everything to do with profits, and nothing to do

with protecting the aquifer at this site.

3.3 Curis Has Not Adequately Addressed Man-Made Preferential

Pathways for the Escape of Acid Mining Solutions.

ADEQ’s BADCT Manual recommends that boreholes and wells should be

plugged and abandoned in accordance with Arizona Department of Water Quality and

USEPA standards.98 Old wells, exploration core holes, and mine shafts create

preferential pathways through which ISL mining solutions can escape hydraulic control

and contaminate drinking water supplies. According to an expert on ISL, ‚The most

critical part of the ISL process is to control the movement of the chemical solutions

within the aquifer. Any escape of these solutions outside the ore zone is considered an

excursion, and can lead to contamination of surrounding groundwater systems. Some of

the most common causes of excursions, identified by international operations in the United

States and across Europe, can be through old exploration holes that were not plugged adequately

. . .‛99 In a 1995 study of uranium in situ leach mining, USEPA found that ‚Vertical

excursions may develop . . . commonly, from wells previously drilled into the aquifer that

were not adequately plugged before mining operations commenced. Vertical excursions are

more difficult to remedy and may require extensive testing to identify the source of the

95 BHP Copper, Florence Project Final Pre-Feasibility Report, Vol. IV (Hydrologic and Metallurgic

Evaluations), at 66 (December 1997).

96 Id. at 67.

97 Id.

98 Arizona BADCT Manual, at 3-46.

99 Gavin Mudd, An Environmental Critique of In Situ Leach Mining, at vi (July 1998) (emphasis

added).

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45

‘leak’.‛100 These excursions present a ‚significant threat to public health,‛ as described

by USEPA in 1980:

One of the common ways by which fluids can enter an

underground source of drinking water is by migration through

improperly abandoned and improperly completed wells. This would

occur if fluids moving laterally within an injection zone encountered an

improperly abandoned or completed well, and, following the path of least

resistance, flowed upward within the well until entering an overlying

underground source of drinking water or overflowing onto the land

surface. Because of the large number of wells drilled in the past, and

because well operation and abandonment have not always benefitted

from close regulatory scrutiny, contamination by this route can present a

significant risk to public health.101

This is not a theoretical threat. In Goliad, Texas, a uranium mining company

drilled numerous exploratory bore holes several years ago for a proposed uranium ISL

project. Experts for the local groundwater conservation district have concluded that the

bore holes allowed poor quality water from an upper aquifer to drain into the lower

drinking water aquifer. Local well owners experienced muddy, dirty water, fouled

filters, and bacterial contamination. Several well owners had to abandon their wells

altogether. The local community continues to oppose the mining efforts to construct a

uranium in situ leach mine in the area, fearful that full-scale commercial mining will

lead to more serious and wide-spread impacts.102 USEPA Region 6 recently refused to

certify an aquifer exemption for the proposed mine, requiring the mining company to

provide evidence that the mine would not impact drinking water resources.103

100 USEPA Office of Solid Waste, Technical Resource Document, Extraction and Beneficiation of Ores

and Minerals, Vol. 5, Uranium, at 30-31 (January 1995) (emphasis added).

101 USEPA, Statement of Basis and Purpose, National UIV Program Docket Control Number D

01079, at 14 (1980).

102 Communication with President, Goliad Groundwater Conservation District.

103 Victoria Advocate, EPA does not certify Goliad uranium mining project (May 19, 2012).

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Similarly, opponents of the Centennial Project uranium ISL mine near Fort

Collins, Colorado appealed USEPA Region VIII’s issuance of a UIC permit based in part

on their position that USEPA failed to consider the impact of improperly abandoned

core holes in the mine area. Old core holes had been filled with drilling mud or even

‚beet pulp‛ for years before Colorado passed laws requiring more stringent

abandonment requirements. The uranium company admitted it could not locate all of

the core holes, but USEPA issued the UIC permit without requiring additional

investigation or protections.104 Thanks to opposition by the local community, USEPA

withdrew the UIC permit in February 2011.105 The mining company, Powertech,

subsequently suspended activity on the project indefinitely.106

But most importantly, Curis’s predecessor has admitted that groundwater

exceedances at the Florence Copper Project site were the result of core holes and defects

in well construction:

Communication between aquifers was determined to be the most

likely cause for exceedances observed at wells M14-GL and O49-

GL. Possible avenues of communication include open holes and

defects in well seals and/or casings. A defect in the casing of one

well was detected and corrected. Two open core holes (one near

each well) were located and sealed. After giving the aquifers time

to equilibrate, tests will be conducted (schedules during the next 60

days) to determine whether the actions described above have

corrected the problems. If it is determined that the actions have not

produced the desired results, BHP will take further action as

needed.107

104 In the Matter of Powertech (USA) Inc., UIC Permit No. CO51237-08412, Petition for Review of

UIC Permit, at 12-17.

105 USEPA Region 8 Letter re Powertech (USA) Inc. Notice of Withdrawal (February 7, 2011);

Colorado Independent, Powertech says no negative connotation to EPA withdrawal of uranium

mining permit (February 10, 2011).

106 Powertech Uranium Corp., Centennial Project, at

http://www.powertechuranium.com/s/Centennial.asp (visited May 30, 2012).

107 BHP Copper Letter to Greg Olsen, ADEQ, at 4 (March 8, 1999).

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47

Given these risks, this is an issue deserving of close attention. But Curis has

downplayed this issue in its submissions to USEPA and ADEQ, ignoring the risk and

refusing to commit to any plan to investigate, locate, and abandon these core holes.

Unfortunately, it appears that ADEQ also may be ignoring this issue, as the agency has

requested almost no information from Curis to support its claims on this issue and has

proposed no additional work by Curis to investigate these holes. ADEQ should not

permit this issue to go unaddressed. Curis should be required to map all known core

holes on and around the State Land parcel; conduct a thorough investigation for lost

and as-yet-undiscovered core holes; and properly seal and abandon all core holes on

and around the State Land parcel before a Temporary APP is issued.

3.3.1 Curis’s mine site contains hundreds of core holes, most of which have

never been located.

The Florence Copper Project site is riddled with core holes, underground mine

works, and lost wells that could serve as conduits for mining solutions to escape the

area of the aquifer designated for ISL mining. Available information indicates that

hundreds of core holes have been drilled at the FCP site over the last forty years. But to

date, Curis and its predecessors have provided only limited information on the core

holes’ location, construction, depth, and other features. ADEQ requested additional

information on core holes in its original request to Curis for additional information.108

Curis has never responded to that request. Unfortunately, ADEQ did not request

information on core holes in relation to Curis Temporary APP, other than to request a

map depicting ‚the locations of coreholes that will be plugged and abandoned . . . .‛109

This is a serious oversight, because the existence of exploratory core holes in and

around the Pilot Project area represents preferential pathways for the movement of

toxic mining fluids.

The only substantive discussion of core holes found in ADEQ’s files on this site

comes from Magma Copper Company’s 1996 Site Characterization Report. There,

108 ADEQ, Comprehensive Request for Additional Information with Suspension, at 6 (September 7,

2011).

109 ADEQ, Comprehensive Request for Additional Information with Suspension, at 9 (May 2, 2012).

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48

Magma asserted that the first company to actively explore the Florence Copper Project

site, Conoco, drilled a total of 686 core holes on the site between 1969 and 1975. Of

those, Magma claimed that 332 were drilled within the ‚primary deposit‛ and 354 were

completed in peripheral areas.110 Magma provides no evidence for its claim that only

686 core holes were drilled by Conoco, or that no other core holes were drilled before

1969 or after 1975 by Conoco or others.

Magma goes on to assert that it began a ‚second phase‛ of core hole drilling in

1993. Between January 1993 and February 1995, Magma drilled 23 ‚pre-feasibility‛ core

holes; 12 holes for material properties testing samples; and two other 6-inch holes for

bulk metallurgical samples. Beginning in February 1995, Magma began a ‚third phase‛

of core hole drilling that resulted in 38 diamond-drilled holes and two 6-inch holes for

metallurgical and geochemical testing.111

Thus, Curis’s predecessors drilled at least 767 core holes of various depths and

diameters across the mine site, including dozens of core holes on the State Land parcel.

But these are only the core holes that Curis and its predecessors have acknowledged.

Anecdotal evidence, including descriptions from former Conoco employees, indicates

that hundreds of other core holes exist throughout the mine site. Neither Curis nor its

predecessors have provided any evidence to ADEQ to support their assertion that only

767 core holes exist. In fact, to our knowledge, none of the mine companies have ever

provided any documentation to support their summaries of known core holes.

In its Temporary APP application, Curis proposes to only close core holes within

500 feet of the Commercial PTF well field. Curis provides information in Figure 8-1 and

Table 9-1 of the application on the "record location"—not the known location—of core

holes within this area.112 Curis admits that previous practice was to backfill with soil

and grout only the top 20 feet of a core hole, meaning the core holes are not visible

today. Curis also admits that some core holes may have collapsed at the surface. But

the only commitment to finding these core holes that Curis makes is to excavate at the

"record locations." Even that commitment is qualified to save Curis money, as Curis

110 Magma Copper Company, Site Characterization Report, at 4-4 (January 1996).

111 Id. at 4-4 and 4-5.

112 Temporary Application, Attachment 9 (Design Documents), at 4.

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49

proposes to look for changes in soil texture and vegetation or surface elevation to "avoid

unnecessary excavation."113 It is absurd to think that Curis can locate 6-inch holes bored

40 years ago through visual clues.

Curis's proposal to "evaluate" alternative geophysical techniques for finding

these core holes is meaningless. Curis only has two years to finish Commercial PTF

activities under the Temporary APP, and needs 12-14 months of that time for ISL

operations. Under Curis's proposal for dealing with core holes, Curis will poke around

for the core holes with a backhoe, then "evaluate" other locating techniques for a while

longer, then maybe employ those techniques to locate the core holes, then abandon the

core holes. That process could take months and Curis doesn't have that much time

under the Temporary APP. Therefore, Curis should be required to employ designated

geophysical techniques to find these core holes before a permit is issued.

It also is not clear what happens if all of the "record" core holes cannot be found.

Will ADEQ allow Curis to operate the Commercial PTF anyway? Will the Commercial

PTF well field have to be moved to a safer location? Will additional monitoring wells

be necessary? These are important questions that should be answered before the permit

is issued so that the answers are subject to public review and comment.

This issue is especially significant given what we know of the history of core

holes in the Commercial PTF area. According to Magma Copper, Conoco reported that

‚exploratory coreholes in the vicinity of the underground workings were abandoned by

grouting prior to the pilot mining activities. The objective of the abandonment activity

was to prevent basin-fill groundwater from migrating through the coreholes into the

underground workings. No indication of the number or exact locations of the

abandoned coreholes was located in project files.‛114 Thus, there are numerous

coreholes in the Commercial PTF area, surrounding the underground mine shafts, that

have been abandoned according to 1970s standards that would not satisfy modern

regulatory requirements. No one knows where these holes are or how many of them

exist. Yet Curis would have ADEQ believe that it has identified all of the coreholes in

113 Id.

114 Magma Copper APP Application, Volume II of V (Site Characterization Report), at 4-2

(January 1996).

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50

the area. Clearly, that is not the case and whatever coreholes Curis has identified

represent only a portion of the holes that actually exist at the Commercial PTF site.

ADEQ should require Curis to immediately disclose all documentation

regarding the location, construction, depth, and use of core holes at this site. Curis

apparently has such documentation, because it has discussed its ability to locate core

holes based upon ‚available survey coordinates.‛115 If Curis’s predecessors possess

some or all of the documentation, ADEQ should obtain the documents from the

relevant companies under its existing subpoena authority.

3.3.1.1 Known core holes represent significant pathways for the

migration of toxic mining fluids.

Even if these are the only core holes on the site, they represent significant pathways

for the migration of toxic mining fluids that should be of serious concern to ADEQ.

Conoco’s core holes appear to have been at least 2.4 inches in outside diameter,

although most likely were 3.03 inches in diameter.116 Of the 332 known core holes that

were drilled over the copper ore body, 72 terminated above the ore body, with the

remaining 260 penetrating into bedrock.117

Magma’s ‚pre-feasibility‛ core holes were drilled to depths of 770 feet to 1,600

feet. Because bedrock began no deeper than 510 feet, it appears all of these were drilled

into bedrock. The two 6-inch metallurgical sampling holes were drilled to 690 and 842

feet. The 38 diamond drill core holes were drilled into the oxide and sulfide bedrock

zones, and the two later 6-inch holes were drilled to 900 and 1,074 feet.118

115 Curis UIC Application, Attachment Q (Plugging and Abandonment Plan), at 4 (March 2011).

116 Magma Copper Company, Site Characterization Report, at 4-4 (January 1996). It is not clear

from Magma’s discussion in the SCR if these outside diameters apply only to the core holes

drilled into the ore body, or also to core holes drilled in ‚peripheral areas.‛

117 Id.

118 Id.

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51

Neither Curis nor its predecessors have presented evidence that any of Conoco’s

nearly 700 core holes were abandoned. In public meetings regarding Curis’s proposed

mine, it has been asserted that the core holes would have collapsed upon themselves,

thereby eliminating preferential pathways for mining fluids. It is ridiculous to believe

that nearly 800 core holes, drilled into bedrock at depths of 1,800 feet and more, would

completely collapse over their entire length so as to eliminate this problem. It is much

more likely that, even if many of the core holes have collapsed or been filled in at the

surface, the holes are still open at depth in the more competent hard rock portions to

serve as conduits for mining fluids and contaminated groundwater.

Thus, at least 767 core holes, ranging in diameter from 2.4 inches to 6.0 inches,

are known to have been drilled by Curis’s predecessors. These holes extend from a few

hundred to well over 1,000 feet below ground surface, thereby penetrating the various

hydrogeologic layers underlying the mine site. In so doing, these core holes present

significant pathways for mining fluids and contaminated groundwater to move

vertically through aquifer and geologic layers. To the extent these core holes were

constructed improperly or have degraded over time, they likely also represent

pathways for fluids to escape the core holes through cracks, gaps, and ruptures in the

casing and move horizontally through the aquifer.

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September 21, 2012

52

Figure 8, Known Core Holes on Curis Property

1000.0

PTFWeU Field

Venieal Scale (feet)

Coaoco WeU 321\IF* Coonlin.ates: 649007.3 I:astia&

7444.:29.1 Northing Total Depth: 2.732 ft bgs

(-1,267.7 ft am.sl)

Curls Property

1:::.: 800.0

600.0

400.0

200 0

0.0 Not to~

•con•hol~s Source: Curis Resot,m;es (A rUona) Inc

Southwest Grou nd-water e Consultants, Inc.

September 2012 Proje4:t B.l816

Application to Am~nd UIC Pemtit .U'396000001 An.achm~ntC - C o1Tect:ive Action PLan \Ven Data T able C-3. Coreholes that P~netrate the Proposed Injection

COREHOLE WELL LOCATIONS

Pinal

Figure

1

SWVP-017778



September 21, 2012

53

3.3.1.2 Curis has not found all of the core holes, does not plan to look

for them, and plans to abandon only a few of the known core

holes.

In the mid-1990s, Magma attempted to locate the 332 core holes that it had

identified as having been drilled by Continental in the area intended for mining.

Magma found only 114. The remaining 218 core holes could not be located ‚due to

agricultural activities.119 Since that time, no additional investigations are known to have

been conducted to locate other core holes in the area.

After 16 years of additional agricultural plowing and earth moving, irrigation,

erosion, rain and dust storms, Curis originally indicated that it would locate known

core holes using ‚available survey coordinates‛ and surface excavation as necessary for

plugging and abandonment.120 Of course, Curis did not mention in its application

materials that its predecessor could not locate most of the holes 16 years ago and

provided no explanation of how it would find the holes today. Curis’s proposed ‚plan‛

to locate and abandon old core holes is almost identical to the one proposed by BHP in

the late 1990’s. Despite Curis’s public assertions to the contrary, no new technology has

been developed and incorporated into Curis’s plans to identify historic core holes, bore

holes and other subsurface structures. Moreover, Curis only planned to plug core holes

that were located within 500 feet of an ‚operational unit‛ or mining block, leaving all

others open during operations.121 If approved, this would permit hundreds of core

holes to remain open as potential conduits for contaminants to drinking water aquifers.

A close review of the information provided by Curis in its UIC application

demonstrates numerous inconsistencies. Magma indicated that 332 core holes were

known to have been drilled by Conoco within the area intended for mining. But Curis

listed only 270 Conoco wells, providing no information regarding the other 62 wells. Of

those 270, Curis also did not indicate which ones had been previously located by

Magma and which ones were among the 218 ‚lost‛ core holes. Magma also indicated

119 Id. at 4-5.

120 Curis UIC Application, Attachment Q (Plugging and Abandonment Plan), at 4 (March 2011).

121 Application to Amend, Attachment 16 (Closure Plan), at 5 (January 2011).

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September 21, 2012

54

that it drilled 81 core holes between 1993 and 1995. Yet Curis listed only 65 Magma core

holes, providing no information on the other 16 holes. In total, Curis listed 340 core

holes that it described as existing within the in-situ mining area and the Area of Review

for the UIC permit. It did not, however, explain why it believes only 340 core holes

exist within these areas, whereas Magma listed 413 core holes within the area intended

for mining.122

Now, in regard to the Temporary APP, Curis is not even offering to look for all of

the core holes on the State Land parcel. Instead, it has provided a list of core holes that

it has chosen to abandon, all of which are located within 500 feet of the pilot test well

field.123 This list includes just 24 of the nearly 800 core holes known to have been drilled

by Curis’s predecessors. Curis also lists 13 of Magma’s core holes as ‚Abandoned

Exploration Core Holes,‛ but Curis has provided no evidence in support of its apparent

assertion that these core holes were properly abandoned. In fact, Curis stated in its UIC

application that none of the 340 core holes in its table had been properly sealed and

abandoned in accordance with modern regulations.124 Nevertheless, Curis depicts these

core holes as ‚abandoned‛ in its site map, apparently intending to take no further

action as to these core holes, despite their proximity to injection and extraction wells.125

ADEQ should clarify which core holes have been previously abandoned and require an

explanation of how abandonment was completed. If abandonment did not satisfy

current standards, Curis should be required to properly abandon such core holes before

injection begins.

Moreover, Curis’s own data indicates that there are dozens of core holes in close

proximity to prominent features of the Commercial PTF:

There are more than a dozen core holes located in the area of the

underground mine shafts.

122 Curis UIC Application, Attachment C (Corrective Action Plan and Well Data), Table C-3

(March 2011).

123 Temporary Application, Attachment 9 (Design Document), Table 9-1 (March 2012).

124 Curis UIC Application, Attachment C (Corrective Action Plan and Well Data), at 2 (March

2011).

125 Temporary Application, Attachment 10 (Site Plan), Figure 8-1 (March 2012).

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September 21, 2012

55

More than a dozen core holes appear to be located directly under on

adjacent to the pipelines that will carry toxic mining solutions from one

side of the State Land parcel to the other.

Two core holes are located within the proposed surface impoundment in

the northwest corner of the State Land parcel.

Two core holes are located next to the SX/EW plant, including one adjacent

to chemical storage tanks.

Numerous core holes are located near existing and proposed monitoring

wells.126

Incredibly, Curis has not included any of these core holes in its list of those to be

abandoned before the pilot test begins. Leaks in the impoundment pond liner, a spill at

a chemical storage area, or a ruptured pipeline are just a few of the events that could

lead to contaminants flowing into these core holes during the pilot project.

Curis’s site map indicates that there are about 140 core holes located on the State

Land parcel. Given that only about 200 core holes have been located (the Continental

core holes found by Magma in 1995 and Magma’s own core holes), it appears highly

likely that many of the core holes depicted by Curis’s figure have not been located.

Unless ADEQ presses Curis for further information and investigation before issuing a

permit, Curis is likely to abandon only a handful of core holes and assert that the

remaining holes simply cannot be found.

In summary, although hundreds upon hundreds of core holes have been drilled

across Curis’s property, only about 200 have been located since 1995. Curis has no plan

to find the remaining core holes, much less a plan to properly seal and abandon them so

that they do not become conduits for toxic mining fluids to migrate through the aquifer.

On the State Land parcel, Curis has identified over 140 known core holes from historical

documentation, although Curis can probably only locate a few of those today. Of those

known core holes, however, Curis plans to abandon only two dozen or so that are in

proximity to the pilot test mine area. The other ten dozen core holes, located near

pipelines, chemical storage areas, impoundment ponds, and other features, will

apparently be ignored.

126 Id.

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September 21, 2012

56

ADEQ should require Curis to locate every core hole depicted on its site map of

the State Land parcel and conduct a thorough investigation for other core holes in the

area. Further, Curis’s proposal to abandon only about 24 of the approximately 140 core

holes known to exist on or near the State Land parcel is appallingly inadequate. Given

the small size of this parcel, the amount and size of facilities that Curis proposes to

squeeze onto it, and the activities that Curis plans to conduct, Curis should be required

to properly abandon all core holes on the State Land parcel before the pilot project

begins.

3.3.2 Underground Mine Workings are Key Geologic Features that Have

Not Been Adequately Considered.

ADEQ’s BADCT Manual mentions underground mine workings in regard to ISL

mining only with respect to mine sites that are using the water table for hydraulic

control, which is not happening at this site.127 But if coreholes are a significant potential

pathways for mining pollutants, then large underground mine shafts certainly must be

considered an even greater risk to the drinking water aquifer.

In the early 1970s, Conoco dug underground workings on the property128 with

shafts on the northern end of Curis’s planned operations. Two mine shafts, nearly five

feet in diameter and 700 feet deep, are connected by an eleven by nine foot horizontal

shaft. Branching off from these main shafts are over a mile of horizontal drift and

crosscut shafts located 800 feet below the surface. These underground shafts are

flooded with groundwater, with the average flow of groundwater into the shafts

estimated at 530 gallons per minute.129 Curis has no plans to close these shafts during

mining operations, despite its intention to inject acid mining solutions into wells around

and directly above these workings.

Figure 9, Proposed Well Field Layout from Curis Draft Reclamation

Plan Submitted to State Land Department


128 SRK Consulting, NI 43-101 Preliminary Economic Assessment for the Florence Project, at 3

(September 30, 2010).

129 Brown and Caldwell, Preliminary Site Characterization Report, at 4-1 to 4-3 (December 1995).

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September 21, 2012

57

Curis has dismissed the risk of these underground shafts with respect to the

Commercial PTF, arguing that the Commercial PTF well field is too far from the

underground workings to have any impact. This argument, however, ignores the fact

that ADEQ apparently plans to issue a commercial mining permit to Curis even before

Commercial PTF operations are completed. As illustrated in Figure 9, Curis apparently

plans to install injection wells throughout the area of underground mine shafts on State

Land. If this is so, then the impact of injecting acid mining solutions through these

mine shafts should be investigated and evaluated as part of the Commercial PTF. Such

a proof of concept is necessary to understand potential issues and impacts and to

develop methods of addressing them. Ignoring these impacts, when ADEQ intends to

permit ISL mining directly over the underground mine workings, is unreasonable and

irresponsible.

3.3.2.1 ADEQ has recognized the dangers posed by the underground

mine workings, but has not forced Curis to address them.

ADEQ has repeatedly recognized—in reviews of both the substantial

modification application and now in the Temporary APP application—the dangers of

allowing ISL mining directly over and through the underground mine workings.

ADEQ’s own Engineering Review Memorandum of Curis’s substantial modification

application revealed that ADEQ recognized Curis’s failure to provide sufficient

evaluation and information on the underground workings, features which ADEQ

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September 21, 2012

58

characterized as a ‚subsurface reservoir‛ and ‚potential long-term discharging facility.‛

ADEQ noted that ‚an experienced individual familiar with this type of site condition‛

should evaluate the underground mine workings and that the evaluation should

include a discussion of engineered controls (grouting, etc.) or other containment

methods. To date, Curis has failed to fully respond to this inquiry and direction from

the agency.

In September 2011, ADEQ specifically required Curis to analyze the potential

risks presented by historic bore holes and wells, underground mine workings, and

geologic contacts.130 Among other things, ADEQ identified the potential for

contaminated mining solutions to travel up to the ground surface through the mine

workings. As explained by ADEQ, ‚*t]he mine apparently has several entrances

(vertical shafts) that could, under the right hydrologic event, provide leach solution to

the surface.‛ The information provided by Curis regarding this other risks associated

with the mine workings was simply ‚not adequate.‛131

Curis never responded to these comments with regard to commercial operations.

But Curis dismissed ADEQ’s concerns as irrelevant in the Temporary APP

application,132 offering only the possibility of future study of the underground

workings.133 Adding insult to injury, Curis then proposed to provide the agency with a

plan to address the underground workings after the commercial operation permit is

issued, completely bypassing public review and comment.

In May 2012, ADEQ once again explained to Curis that underground workings

can hold process solutions for long periods of time before discharging to groundwater.

ADEQ indicated that water within the workings should meet AWQS or pre-operational

water quality before in-situ operations begin. In response, Curis claimed that the water

in the underground workings would not be impacted by injection during Commercial

PTF operations because the well field was cross-gradient or down-gradient from the

mine shafts and more than 500 feet away. Along with this statement, Curis enclosed a

130 ADEQ September 2011 Deficiency Letter at 10, HD ¶32.

131 ADEQ Sept. 2011 Deficiency Letter at 24, EC ¶5.

132 Temporary Application at §§ 9.5.2, 11.10.2.1, 14C.4.4.

133 Temporary Application at 8.2.7

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September 21, 2012

59

video log of the primary shaft devoid of any discussion or analysis. Water quality data

from an unidentified onsite shaft sample was provided along with a promise to collect

two additional samples prior to beginning operations.134

ADEQ also requested updated closure and post-closure costs and compliance

measures.135 In response, Curis merely referred the agency to the reclamation plan it

submitted to the State Land Department, not even giving the agency (and the public)

the courtesy of enclosing the report. In actuality, Curis has not submitted a formal

reclamation to State Land. To date, it has submitted only a draft reclamation plan that

provides little information on this subject.

It appears likely that ADEQ will issue a Temporary APP permit with no

requirement that Curis address these issues. Given the known risks of underground

mine workings recognized by ADEQ and the almost complete absence of any

meaningful analysis, it is imperative that ADEQ require Curis to conduct detailed

investigation into the status of the workings along with thorough analysis by a qualified

expert and then follow-up on this information by imposing conditions designed to

protect the soils, subsurface and groundwater from potential environmental

degradation.

3.3.2.2 Curis’s proposal to monitor for subsidence is inadequate.

Another concern expressed early on by ADEQ, was the risk of subsidence posed

by the underground mine workings, a risk that Curis has failed to adequately analyze.

In its initial submittal, Curis didn’t even provide ADEQ with an underground map of

the actual workings.136 In the Temporary APP application, Curis provided mere lip

service to the issue claiming that the underground workings ‚represent very little risk

of subsidence at ground surface.‛137 Little support is provided for this conclusion other

134 Curis Arizona Response to ADEQ’s May 2, 2012 Request for Information, Response to

Comment 11.

135 May Deficiency Letter, Item 11.

136 ADEQ Sept. 2011 Deficiency Letter at 24, EC ¶5.

137 Temporary Application at 9.5.2.

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60

than a brief description of previous studies of the Casa Grande Santa Cruz Joint

Venture Site work to study subsidence in the area as a whole.

Underground mine workings pose dangers of subsidence and earth fissuring

that can adversely affect surface structures such as pipelines. Their existence can also

create preferential pathways for migration of sulfuric solution into area groundwater.

In its BADCT Manual, ADEQ has recognized that ‚*g+roundwater declines of as much

as 300 feet in the alluvial basins in central and southeastern Arizona are known to have

caused subsidence of as much as 20 feet < *S+olution extraction of salt*,+<hard rock

mining and other underground excavations <also can produce large amounts of

subsidence. In-situ leaching may result in subsidence through dissolution of

underlying rock. < If subsidence is not uniform beneath the facility, different rates or

amounts of subsidence can result in horizontal or vertical strains that can impair the

integrity or functioning of facility components such as wells, piping systems, and

embankments. It can also cause earth fissuring that can provide preferred pathways for

seepage migration to the water table.‛138

Figure 10, Excerpt of Curis’s Revised Figure 8-1

As can be seen in the excerpt from Figure 10 above, Curis’s Pilot design includes

a long pipeline (in black) connecting the well field to the beneficiation facilities

designed to carry acid- and chemical-laden pregnant leach solution and lixiviant for

reinjection 139 right across multiple historic underground mining shafts (depicted in

brown). And as recognized by ADEQ itself, underground mine workings pose a

138 ADEQ BADCT Manual at 3-42 (citations omitted).

139 Temporary Application at § 9.3.2.

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61

significant subsidence risk that can lead to pipeline system failures. If Curis’s proposed

pipeline settles and cracks or breaks or otherwise fails, chemical-laden pregnant leach

solution and lixiviant could spill out to the surface soils, potentially leach into the

subsurface, and contaminate area groundwater.

An April 2012 draft of ADEQ’s request for additional information noted the

problems inherent in Curis’s pipeline design, in that it traversed several underground

mine workings. Specifically, the agency draft indicated that because the proposed

pipeline crosses over underground mine works, an independent subsidence study was

necessary. ADEQ’s draft also noted that subsidence is an ‚inevitable consequence of

underground mining‛, that the effected surface is generally larger than the extracted

area, that faults generally increase the risk of subsidence, that water reduces the

strength of the underground rock and that effects to the surface may not be visible for

some time.140

These concerns were inexplicably eliminated from the final request for

information issued to Curis in May 2012, although ADEQ did request that Curis

provide a subsidence study that included plans for quarterly monitoring.141

Nevertheless, the risk remains. Thorough characterization and preventive measures

related to the historic underground workings are imperative, not irrelevant. 142 The risk

of subsidence and uncontrolled groundwater leaching inherent in this design poses a

significant risk to Florence’s drinking water supply. Instead of requiring Curis to

merely monitor subsidence conditions during Commercial PTF operations, ADEQ

should require Curis to hire a qualified expert to thoroughly study and analyze

subsidence risks associated with the site and Curis’s operations before issuing a permit

and allowing Curis to begin those operations.

3.3.3 Curis has not addressed the impacts of on-site wells.

Curis plans to leave at least three on-site groundwater wells open during

Commercial PTF operations. Two of these wells are irrigation production wells,

140 ADEQ Draft Request for Information, comments 29-30 (April 25, 2012).

141 ADEQ Request for Information, Item 25, at 11 (May 2, 2012).

142 See ADEQ BADCT Manual at 3-42.

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operation of which could significantly affect groundwater flow throughout the

Commercial PTF area. Curis has made no effort to address potential impacts from these

wells, which could affect groundwater flow, hydraulic control, and groundwater

quality.

3.3.3.1 Curis’s proposal to leave two irrigation production wells open

during Commercial PTF operations is unacceptable.

The Bureau of Indian Affairs owns at least three wells that are located just south

of the Northside Canal. BIA-9 is near the southwest corner of the State Land Parcel; BIA

10B is just south of the parcel and next to the underground mine workings; and BIA-10

is just east of the State Land Parcel. These wells supply irrigation water for the San

Carlos Irrigation Project. Operation of these three production wells has significant

impacts on local groundwater flows at the mine site and within the Commercial PTF

area. Curis, however, has provided no information on the scope of those impacts.

BHP proposed to abandon two of these wells before commercial production,

apparently under an agreement with BIA to drill two replacement wells in other

locations that would not impact ISL mining. It was never clear whether Curis planned

to honor that agreement. Although Curis asserted that there would be no groundwater

pumping of irrigation wells BIA-9 and BIA-10B during Commercial PTF operations, it

never committed to actually abandon and plug the wells.143

According to ADWR records, BIA-10B was completed in August 1972. The well

registration form appears to indicate that the owner is not sure what the well casing is

constructed of, indicating the type of casing as ‚? Steel.‛ The well is 2006 feet deep and

has a pump capacity of 1,300 gallons per minute. BIA-10B is screened from 200 feet to

1,909 feet below ground, such that it will pull water from throughout the drinking

water aquifer and underlying ore bodies.144 BIA-9 was completed in April 1965 and is

500 feet deep. It has a steel casing and a pump capacity of 1,600 gallons per minute.145

143 Curis’s Response to ADEQ’s May Deficiency Letter at Response to Comment 5.

144 ADWR Well Registration No. 55-621949 (June 12, 1982).

145 ADWR Well Registration No. 55-621948 (June 12, 1982).

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There is no doubt that wells of this size will seriously affect groundwater flow in

the Commercial PTF area. Furthermore, if these wells are like most San Carlos

Irrigation Project wells in the area, they have been poorly maintained since

construction. It is likely that the casings and screens are heavily damaged and corroded

and that seals are inadequate or non-existent. Cascading groundwater could exist

within the well structure. When not in use, these wells represent vertical pathways for

mining pollutants.

Apparently, Curis has now made clear that it has no intention of abandoning

either BIA well.146 If Curis is not required to properly plug and abandon these wells,

use of the wells will have serious impacts on groundwater flow in the Commercial PTF

area, rendering Curis’s previous groundwater models worthless and impairing the

ability to maintain hydraulic control.

3.3.3.2 Curis’s proposal to obtain water for Commercial PTF

operations from a production well inside the PTF area deserves

additional scrutiny.

Apparently, Curis proposes to use Well PW2-1147 to supply makeup water and

other water needs for the Commercial PTF.148 The information on this well provided by

Curis is not consistent with the information in the well registration documents. But it

appears that this well was originally a test or monitor well completed by Magma

Copper in 1994. ADWR records indicate that the well was drilled to 600 feet below

ground surface and is screened from 325 to 580 feet below ground surface. Based on

needs discussed in the application, it appears that Curis plans to pump approximately

15 gpm from PW2-1 for use as makeup water and incidental facility water uses.149

146 ADEQ, Letter re Inadequate Response to Substantive Deficiencies, at 6 (September 10, 2012).

147 ADWR Well Registration No. 55-542057.

148 Daniel Johnson Letter to Richard Mendolia, Attachment 20, Drawing No. 000-CI-005

(Production Test Facility) (May 23, 2012) (describing PW2-1 as the ‚proposed water source‛).

149 Curis’s water needs are not entirely clear. Curis has indicated a need for 96 acre-feet of

groundwater the first year of Commercial PTF operations and 325 acre-feet the second, with no

groundwater demands afterward. Curis Response to ADEQ’s May Deficiency Letter, Response

to Comment 27. Curis has also described its water needs as 60 gpm for as long as 14 months

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Significantly, PW2-1 is located within the underground mine workings area.

ADEQ should carefully assess whether its use could affect groundwater flows and

whether it could draw contaminants from the well field into the underground mine

workings. ADEQ should also assess whether it is wise to convert PW2-1 to an active

production well located within an area slated for ISL mining. Even if only minimal

amounts of water are pulled from the well during Commercial PTF operations, Curis

should explain whether that same well will supply commercial operations, thereby

requiring much higher extraction rates and more substantial impacts to local

groundwater conditions. Finally, Curis should supply water quality results for this well

and analyze the impact of those results on their geochemical model.

3.4 Curis Failed to Consider Alternative Discharge Control Measures.

ADEQ regulations require a description of the ‚alternative discharge control

measures‛ that Curis considered to prevent acid mining solutions from contaminating

the drinking water supply.150 For an individual BADCT design applicable to the

Commercial PTF well field, Curis should have followed a process that included:

Development of a range of alternative discharge control systems;

Screening these alternative systems by estimating the relative degree of

discharge control;

Selection of the most promising alternative systems for more detailed

analysis;

Refinement of designs for the selected alternative systems;

Comprehensive estimates of discharge control for the selected alternative

systems; and,

Selection of BADCT design.151

Although Curis purports to have performed this analysis, in reality it has not. Curis

merely makes the conclusory statement that ‚*t+he reference design for the PTF involves

with a subsequent demand of 260 gpm for about 9 months. Id. At Response to Comment 22. It

appears Curis will obtain some water needs from the Commercial PTF recovery wells.

150 Ariz. Admin. Code § R18-9-A202(A)(5)(a)(i).


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the use of ISCR technologies because neither underground mining nor open pit mining

of the Poston Butte copper deposit are commercially feasible.‛152 Nothing in Curis’s

application explains why alternative locations, designs, operating conditions and the

like were not explored and analyzed prior to presenting the proposed approach to the

Commercial PTF well field.

Magma Copper’s 1996 application considered a variety of alternative design

control technologies, including a comparison of a grout curtain to barrier wells as

hydraulic control mechanisms.153 Magma also evaluated closure-related alternatives,

including inherent attenuation and the introduction of cross linking polymers or

neutralizing agents.154 Curis relies entirely on Magma’s fifteen-year-old study for its

BADCT design and has done no additional work to review or update the design.155 It is

hard to believe that within the last fifteen years there have been no advances in mining

technologies and groundwater monitoring developments that Curis could have

examined as alternatives to the proposed well field design. There are volumes of

publicly-available materials on ISL well field design at uranium mines across the

country that Curis could have reviewed for alternative designs, methods of improving

capture, and design errors or flaws to be avoided. It is also difficult to fathom why

Curis would not examine other alternatives in light of land uses that have changed

drastically since the 1990s around Curis’s proposed mine. ADEQ should not make a

permit decision until Curis has met this basic individual BADCT requirement of

examining alternative designs.

3.5 Curis Failed to Consider Alternative Sites and Properly Evaluate

Site-Specific Criteria.

Site selection analysis is the first step in evaluating alternatives.156 Curis has

failed to consider any site alternatives. Instead, Curis merely states that the Commercial

152 Temporary Application, Attachment 11 (BADCT Description) at 10, § 11.10.

153 Magma’s 1996 APP Application, Volume I, at § 4.5.3.

154 Id.

155 Temporary Application, Attachment 11 (BADCT Description) at 10, § 11.10.


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PTF well field ‚is the only site where injection and recovery wells will be used for in-

situ operations in association with this application.‛157 There is no discussion or

evaluation of the various portions of the State land parcel on which the well field could

be located considering ore reserves, preferential pathways, surface features, and other

relevant factors. There is no discussion of why the selected location was chosen when

Curis apparently plans to begin commercial mining on opposite end of the State Land

parcel, working its way from the southeast to the northwest.158 Nor is there any

discussion of whether or how the selected well field location is representative of

hydrogeologic conditions on the rest of the mine site.

For instance, one factor that should have been considered in selecting a site is

whether the wells could be arranged according to fracture geometry, such that their

placement ensures the greatest degree of hydraulic control. But Curis indicates that the

site was not chosen based on fracture geometry. Instead, the well field location is based

on ore characteristics like ore thickness and copper grade—commercial, not

environmental considerations.

Thorough analyses of site-specific factors are key to evaluating the individual

BADCT demonstration for ISL mining.159 ADEQ’s BADCT selection guidance is less

helpful with respect to ISL mining because that guidance ‚is necessarily more general

than for other types of facilities due to the higher degree of dependence on site specific

factors‛ at ISL mines.160 Curis’s application completely fails to evaluate key site-specific

factors as required.

157 Temporary Application, Attachment 11 (BADCT Description) at 12, § 11.10.1.2.4.


159 Proper methods for obtaining hydrologic control at a site necessarily depend upon site-

specific conditions, such as hydrology, geology, climate, etc. ‚BADCT must be determined on a

site specific basis by evaluating the degree that alternative discharge control systems minimize

the addition of pollutants to the protected aquifer.‛ ADEQ BADCT Manual at 3. ‚*N+o single

technology or group of technologies can be mandated as appropriate for all discharge control

systems. Rather, multiple <Demonstrated Control Technologies may be appropriately used to

arrive at a BADCT design for a specific facility at a given site. Then, based on a facility’s status

as new or existing, the criteria described in A.R.S. 49-243.B.1 must be applied to that particular

site to determine which DCTs are appropriate for that facility.‛ Id.


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For instance, as discussed elsewhere in these comments in detail, key

hydrogeologic and geotechnical considerations have not been adequately addressed.

According to ADEQ, ‚*s+ince the performance of in-situ leach facilities are extremely

dependent on site specific geotechnical and hydrogeologic conditions, a detailed site

characterization is critical.‛161 Both hydrogeology and structural geology in both the ore

body and the surrounding area are ‚usually of key importance to solution control.‛162

Curis’s application is not supported by thorough, current-day site characterization

evaluating site-specific geotechnical and hydrogeologic conditions as required by

ADEQ’s own BADCT Manual. Reliance on fifteen-year-old design technologies and

data does not satisfy the requirements for a Temporary APP permit.


162 Id.

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4 Best Available Design and Control Technology—Runoff

Pond

ADEQ allows an applicant to meet certain listed standards, known as

prescriptive BADCT, for non-storm water ponds and process solution ponds. If the

standards are met, BADCT is deemed to have been demonstrated, pending ADEQ

approval.163 But prescriptive BADCT may be prohibited if certain site-specific geologic

hazards are present, such as areas known to be prone to excessive subsidence, facilities

in the vicinity of active faults, and in locations of known geologic instability.164

4.1 ADEQ Should Closely Scrutinize Curis’s Use of Prescriptive

BADCT in an Area of Known Instability.

Because of the proximity of site fractures and faults, potential instability due to

historic underground mine workings, groundwater infiltration from nearby unlined

canals and the Gila River, and collapsing soils within the vicinity of the Gila River, site-

specific factors exist that cast doubt upon the appropriateness of using prescriptive

BADCT for the runoff pond and surface impoundment. ADEQ has recognized that

conditions affecting the use of Prescriptive BADCT include facilities located in areas of

known geologic instability, in areas prone to excessive subsidence, and in the vicinity of

active faults.165 Curis should be required to conduct additional site-specific testing and

analysis and then put in place more stringent BADCT measures with respect to the

ponds as necessary.

As discussed earlier, core holes also exist in the area proposed for the surface

impoundment. Based upon Curis’s map of core holes that will be abandoned and those

that will remain on State Land, it appears that core holes in the impoundment pond will

not be abandoned. This means open coreholes will be left beneath millions of pounds



165 ADEQ Presentation, Individual APP Applications, Best Available Demonstrated Control

Technology (BADCT) for Facilities other than Wastewater Treatment Plants (October 21, 2010).

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of contaminated wastewater. Curis has also indicated that it does not plan to abandon

existing wells and coreholes beneath the mining solutions pipelines because the

pipeline trenches will be lined.

In both these situations, a hole or tear in a liner could release contaminants into

coreholes, creating vertical migration of contaminants and possibly polluting the

drinking water aquifer. Rather than address this risk by properly abandoning these

coreholes, Curis has elected to save money by leaving the coreholes open in these high-

risk areas.

4.2 ADEQ Should Require Additional Clarification Regarding Curis’s

Intended Uses of the Runoff Pond.

Process Solution Ponds are impoundments that normally and regularly contain

mining process solutions as a normal function of facility operations. Non-Storm Water

Ponds also are impoundments that receive mining and process solutions, but the

solutions must either receive only solutions with low concentrations of pollutants or

must hold process solutions for only a short period of time, such as during operational

upset events or storm events.166 Non-Storm Water Ponds are subject to less stringent

regulation than Process Solution Ponds

Curis portrays its ‚Runoff Pond‛ as a Non-Storm Water Pond. In its description

of runoff pond contents, Curis lists, among others, hydrated lime solution, raffinate,

PLS, pH-neutralized solutions of raffinate or PLS, and sulfuric acid.167 Process solutions

is a term defined in regulation to mean ‚pregnant leach solution, barren solution,

raffinate, or other solution uniquely associated with the mining or metals recovery

process.168 Clearly raffinate, PLS and barren solution are process solutions. The lime

solution as well is necessary to neutralize raffinate and thus is another form of solution

uniquely associated with mining and hence a process solution.

166 Arizona BADCT Manual at 2-5.

167 Temporary Application, Attachment 11 (BADCT Description), Table 11-2.

168 Ariz. Admin. Code § R18-9-101(31).

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Although Curis indicates that contaminated mining solutions in the Runoff Pond

will be ‚promptly‛ recirculated into the leach system or pumped to the Impoundment

pond, it does not define ‚prompt.‛ In fact, Curis hedges on how long fluids may be

stored in the Runoff Pond, stating that the pond will be kept dry ‚to the extent

possible.‛169 ADEQ needs more detail on the operation of the Runoff Pond to ensure

that it truly meets the requirements to qualify as a Non-Storm Water Pond. Otherwise,

Curis should be required to treat this as a Process Solution Pond.

Curis’s proposals in regard to the Runoff Pond are lacking in other ways as well.

Despite the fact that ADEQ alerted Curis to the fact that the proposed Runoff Pond

receives stormwater in contravention to typical BADCT designs that direct stormwater

from rooftops away from non-stormwater ponds,170 Curis still includes the stormwater

from its Electrowinning Building roof surfaces into the Runoff Pond. 171 Curis

completely ignored ADEQ’s comment.

169 Temporary Application, Attachment 11 (BADCT Description), Table 11-2.

170 ADEQ May Deficiency Letter Item 20.

171 Curis’s Response to ADEQ’s May Deficiency Letter, Attachment 20, M3 Runoff Pond Design

Report at 1.

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5 Curis Has Failed to Demonstrate that It Can Comply with

AWQS at the Appropriate POC.

5.1 Curis’s Proposed POC Wells Fail to Protect Drinking Water Uses.

For ADEQ to approve the permit, Curis must demonstrate that pollutants

discharged will in no event cause or contribute to a violation of Aquifer Water Quality

Standards (AWQS) at the Point of Compliance (POC) or further degrade aquifer quality

at the POC if at the time of permit issuance the AWQS are already exceeded.172 As you

know the POC is ‚the point at which compliance with aquifer water quality standards

shall be determined‛ and is to be ‚a vertical plane downgradient of the facility that

extends through the uppermost aquifers underlying that facility.‛173 Importantly, the

POC must be located to ensure protection of all current and reasonably foreseeable future

uses of the aquifer.174

In order to accurately detect possible excursions and protect groundwater, POC

wells must be appropriately located, adequately designed and constructed, and

properly operated. Both horizontal distribution and vertical depth of POC wells must

be adequate to detect potential excursions. There must be a sufficient number of POC

wells which also must be properly located in order for them to be of any use at all in

detecting potential excursions and protecting downgradient water quality. As currently

permitted, Curis’s POC wells are essentially worthless because they are inadequate in

location, number and depth.

5.1.1 Drinking Water is the Aquifer’s Current and Reasonably Foreseeable

Future Use.

ADEQ must consider the risk to nearby drinking water sources, other area

groundwater users, and the surrounding area as a whole in setting the POC and

172 Ariz. Rev. Stat. § 49-243(B).

173 Ariz. Rev. Stat. § 49-244.

174 Ariz. Rev. Stat. § 49-244(3) (emphasis added).

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determining whether Curis can meet the statutory standards at that POC. Curis’s

application characterizes the area as if it is still 1997 a time when there were no nearby

groundwater uses. Nothing could be further from the truth. As explained in more

detail in Section 3.1 of these Comments, the aquifer into which Curis proposes to inject

acidic mining solution is a drinking water aquifer. In fact, it is a major drinking water

supply for the Town of Florence and its residents. We implore ADEQ to comply with

its statutory obligation by recognizing and protecting the current and reasonably

foreseeable future drinking water use of this aquifer.

Curis’s application minimizes current uses of the aquifer and completely fails to

identify reasonably foreseeable future uses. Curis attempts to show that vicinity wells

are minimal, mostly irrigation in nature, with few downgradient of the proposed

Commercial PTF. After ADEQ pointed out Curis’s failure to even mention area wells

and groundwater uses,175 Curis added to its Commercial PTF application Figure 7-2, a

depiction of wells within 1.5 miles of the Pilot. The figure and associated table of data,

however, still fails to accurately capture the relevant well information. For example,

SWVP’s Well No. 627648 is inaccurately portrayed as a mineral exploration well,

despite ADWR records listing it as a water production well. Additionally, SWVP’s well

numbers 627617 and 627610 should be designated as downgradient. ADEQ should

require Curis to revise its application and correctly identify the current and reasonably

foreseeable drinking water uses of the aquifer.

In terms of reasonably foreseeable groundwater uses, the Town of Florence has

already identified the aquifer as a drinking water source. According to a letter written

to ADEQ, the Assured Water Supply Plan of the Town of Florence identifies the Merrill

Ranch water and wastewater facilities as water resources that it will utilize to maintain

a sustainable future within the Pinal Active Management Area,176 including proposed

wells that will be located directly downgradient of the Curis mine. In order to prevent

contamination of the aquifer, it is imperative that ADEQ establish multiple POCs with

numerous POC wells designed to protect the aquifer for drinking water use.

175 See ADEQ’s September Deficiency Letter at 2 (HD ¶1).

176 Town of Florence letter to ADEQ’s Carrolette Winstead (July 22, 2010.

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The current and future land uses reflect the need to rely upon the aquifer for

drinking water purposes. Curis attempts to minimize its proximity to Anthem and its

inclusion in a master planned community (or in the ‚Pilot’s‛ case, being surrounded by

a master planned community). The application also tries to show Curis’s proposed

Commercial PTF as being in the middle of undeveloped desert land with the majority of

nearby development being agricultural in nature. Yet the proposed Commercial PTF is

less than 2 miles from a well-developed residential community and is essentially an

island in the middle of the Town of Florence. And one need only look at the Town of

Florence’s General Plan for what is anticipated for land uses within the vicinity of

Curis’s proposed mine. As discussed in detail within Section 1 of these comments, the

area surrounding Curis’s proposed Commercial PTF has drastically changed since the

late 1990’s when the site was previously permitted and when many of the studies upon

which Curis now relies were actually conducted. The aquifer into which Curis

proposes to inject sulfuric acid solution is and will be used for drinking water purposes

and must be protected for such uses.

5.1.2 POC Wells Are Not Located to Protect the Aquifer for Drinking

Water Uses.

In order to determine the appropriate POC, the Pollutant Management Area or

PMA and the Discharge Impact Area or DIA must be determined. The PMA, is defined

as ‚the limit projected in the horizontal plane of the area on which pollutants are or will

be placed. The pollutant management area includes horizontal space taken up by any

liner, dike or other barrier designed to contain pollutants in the facility. If the facility

contains more than one discharging activity, the pollutant management area is

described by an imaginary line circumscribing the several discharging activities.‛177

177 Ariz. Rev. Stat. § 49-244(1).

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Figure 11, ADEQ Depiction of Typical POC, PMA and DIA Arrangement

Although Curis fails to describe the PMA in its application submittals, it appears in

Revised Figure 12 below (the line depicted in black) as encompassing the Commercial

PTF well field, runoff pond, and surface impoundment. This is a large area for which

adequately located POCs and POC monitor wells should be established. Curis’s

proposed POC monitor wells are clearly inadequate.

The DIA is ‚the potential areal extent of pollutant migration, as projected on the

land surface, as the result of a discharge from a facility,‛178 and is defined for the

expected life of the facility through a hydrogeologic study. The study must also

demonstrate that the discharge will not cause or contribute to an AWQS exceedance or

in the case of an existing AWQS exceedance that no additional degradation will occur.179

Both a map of the DIA and an explanation of the methodology by which the DIA was

defined are required in an APP application.180 Despite this requirement, Curis admits

that ‚no significant additional hydrogeologic characterization activities have been

conducted at the PTF site and surrounding vicinity since the Brown and Caldwell

(1996a) study was completed.‛181 Reliance upon these 1996 studies fails to account for

178 Ariz. Rev. Stat. § 49-201.

179 Ariz. Admin Code. § R18-9-A202(A)(8).

180 Ariz. Admin. Code § R18-9-A202(A)(8)(b).

181 Temporary Application at 14A.3.1.

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September 21, 2012

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the significant area changes that have occurred in the last 16 years. Given the

drastically changed area landscape with companion groundwater use changes, it is

hard to believe that ADEQ would allow Curis to rely on this outdated hydrogeologic

study. ADEQ should require Curis to conduct its own hydrogeologic study accounting

for current-day conditions and reasonably foreseeable future downgradient

groundwater uses.

Figure 12, Curis Figure 8-1 (Revised May 10, 2012)

Aquifer water quality standards must be met at the POC or multiple POCs, in the

case of a large site. The POC is a vertical plane downgradient of the project extending

through the aquifer and extraction zone. Points of compliance are to be located so that

they ensure protection of all current and reasonably foreseeable future uses of an aquifer.182

Factors to be considered in setting the POC include the volume and characteristics of

182 A.R.S. § 49-244(3) (emphasis added).

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pollutants, practical difficulties associated with the implementing water pollution

control requirements, water conservation and augmentation, and the site-specific

characteristics of the facility such as climate, hydrology, geology, soil chemistry and

aquifer pollutant levels.183

Figure 13, ADEQ POC Location Diagram

Inappropriate POC locations are one of the more common deficiencies noted in

APP applications and Curis’s permit submittals are no different. Curis’s proposed POC

monitor wells are far from the PMA and unlikely to detect potential contaminants until

years after the pilot’s monitoring is complete and commercial operations have likely

been well underway. As discussed in detail in the comments below, Curis appears to

have selected the POC wells downgradient of the Commercial PTF well field based

upon financial considerations rather than scientific and technical considerations. It was

cheaper to use existing wells than properly locate and drill new POC wells.

Revised Figure 14A-38 depicts Curis’s version of the DIA five years after

closure184 based on sulfate migration as indicated by Curis’s geochemical modeling.185

An examination of Curis’s Figure 14A-38 (see excerpt below) reveals that the POC

monitor wells are well outside the DIA. Curis’s POC well placement is completely

183 Ariz.Rev.Stat. § 49-244(3).

184 Curis’s Response to ADEQ’s May Deficiency Letter, Attachment 6; see also Curis’s Temporary

Permit Application, Vol. 3, Figure 14A-38.

185 Temporary Application at Attachment 14A.

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inappropriate. Even if Curis lost control of its injected acidic solution, it is possible that

the proposed wells would not detect the excursion until five or more years later.

Apparently Curis is correct in asserting that its Commercial PTF can be operated

without experiencing excursions – if the wells designed to monitor those excursions are

placed so far away that they will not detect the excursion until many years later. The

Commercial PTF as proposed by Curis is guaranteed to appear successful because there

is no way excursions will show up in Curis’s monitoring within the permit’s monitoring

period.

Figure 14, Excerpt of Curis Figure 14A-38 showing the DIA/sulfate plume

& proposed POC wells

The concern that the POC monitor wells are too far from the Commercial PTF

well field is highlighted by our own analysis of local conditions. At injection rates of

11,000 gpm, the flow rate incorporating off-site pumping of proposed future off-site

production wells was estimated to be 0.66 feet per day. Applying this flow rate, it

would take less than 3 years to travel 700 feet to the POC wells. It is expected that with

the lower injection rates proposed for the Commercial PTF and the lack of significant

pumping from off-site wells during the Commercial PTF, the actual rate of contaminant

flow would be much less than 0.66 feet per day. Using that assumption, it may take as

many as 5 years or more for contaminants to be detected in the proposed POC wells.

Because the actual rate of contamination flow may vary significantly based on

numerous unknown factors, ADEQ should require additional monitoring between the

Commercial PTF well field and the proposed POC wells along with multi-level

sampling in the observation wells. Otherwise, a failure to see standard exceedances

during the monitoring period would not demonstrate hydraulic control but instead

would be the result of wells placed too far from the injection/extraction field. Instead of

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demonstrating hydraulic control, Curis’s POC wells would be just another example of a

mine where exceedances were not detected until years later, similar to the experience at

uranium mines across the country.

Curis proposes only 7 POC wells for the Commercial PTF with one in the vicinity

of the surface impoundment and the others north and northwest of the well field. As

currently depicted by Curis, 4 of the 7 POC wells,186 greater than fifty percent of them,

are placed in areas characterized by Curis as ‚potentially downgradient.‛ Although we

disagree with Curis representation that the groundwater gradient is exclusively to the

extreme northwest, it would be expected that the majority of their proposed POC wells

would be at locations that in their opinion would be downgradient and not ‚potentially

downgradient‛. Although we believe this characterization is inaccurate, if you accept

Curis’s depiction of groundwater flow direction then Curis should have the majority of

its POC monitor wells in the northwestern direction.

Curis proposes even fewer Commercial PTF POC wells than BHP used in the

previous pilot. Review of groundwater data and interpretations of flow direction maps

prepared using the BHP data indicate that the number of POC wells used in the BHP

pilot was inadequate. Because the BHP Pilot did not generate data points for the

western-most and southwestern-most areas, a true determination of local groundwater

flow direction cannot be made. This lack of data has led to proposed Commercial PTF

POC wells that are inadequate in both number and location with a complete lack of

coverage to the west, south and southwest.

The agency previously questioned Curis’s proposed POC well placement and

adequacy, in both their September and May Deficiency Letters.187 Even so, as currently

proposed the POC are inadequate and fail to account for varying groundwater flow

directions as demonstrated by previous area groundwater monitoring. Currently, there

are no proposed POC wells located directly west and southwest of the Commercial PTF,

even though historical groundwater flow direction maps suggests that flow has

alternated from the northeast to the west. Also, depending on the rate of pumping from

186 Figure 7-2 labels wells No. 55-549172, 55-555831, 55-555824, and 55-547813

187 ADEQ’s September Deficiency Letter at 7-8 (HD ¶25); ADEQ’s May Deficiency Letter at Item

5.

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off-site agricultural wells, flow direction could be towards the southwest. ADEQ

should require POC monitor wells at each of the downgradient directions as

demonstrated through testing over time. Merely because one direction is not

downgradient all year long, does not mean that ADEQ should disregard it. Instead,

failure to account for that downgradient pathway, even if sporadic in nature, would

allow an excursion to go undetected and left untreated allowing contamination to flow

toward existing and future drinking water sources.

Curis’s proposed POC wells also fail to account for area mounding and local

recharge. In areas exhibiting mounding, ADEQ has previously represented that POCs

may be required radially. According to Curis’s own application, groundwater

mounding is already apparent in the area.188 So it is imperative that ADEQ require

Curis to add POC monitor wells radially around the discharge areas to detect potential

contamination caused by groundwater mounding or exacerbated by Curis’s

Commercial PTF. Additionally, it appears that mounding can contribute to western

flow components189 and allow acidic mining solution to migrate off-site.

Curis also fails to address the potential detrimental effects of local recharge from

the nearby unlined canals on the Pilot’s injection of sulfuric acid and Curis’s ability to

maintain hydraulic control. Although ADEQ highlighted this issue for Curis in the

September Deficiency Letter190 and again in the May Deficiency Letter191, Curis

dismissed it as a non-issue for their Pilot operations. Similarly, ADEQ asked Curis to

evaluate potential impacts from wastewater treatment plant recharge and the potential

impacts from the mine on recharge.192 But once again, despite the agency’s prompting,

it does not appear that Curis has adequately addressed recharge. Curis should be

required to include in its modeling all known aquifer stresses including those posed by

recharge.

188 Temporary Application at §§14C.2.6, 14C.2.6.2.

189 Id.

190 ADEQ September Deficiency Letter at 11 (HD ¶37).

191 ADEQ May Deficiency Letter at Item 16.

192 ADEQ September Deficiency Letter at 22 (HD ¶78).

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5.1.3 Curis’s Overall POC Well Field Design Is Based Upon Convenience

to Curis, Rather Protecting the Aquifer for Drinking Water Uses.

The well design is also deficient and appears to be an attempt to use existing

wells, instead of drilling and installing proper wells specific to this pilot. First of all,

Curis’s proposed injection wells contain perforations of 400 feet. If injection wells are

perforated at 400 feet, then Curis needs to install a number of observation and

monitoring wells that cover that depth. POC wells M23-UBF, M22-O, M15-GU, and

M14-GL are located in an area that Curis has identified as being ‚potentially down-

gradient.‛193 It is unacceptable that two-thirds of the POC wells are located in areas that

Curis does not classify as downgradient. POC well M23-UBF (located in the

‚potentially down-gradient‛ cluster of wells) is perforated from 210 to 250 feet and is

proposed to monitor water in the UBFU. Curis does not propose to conduct any

monitoring of the UBFU in the ‚down-gradient‛ cluster of wells as the uppermost

water to be monitored is in the LBFU at 500 feet in POC Well M54-LBF. This appears to

be an inconsistent monitoring plan with no explanation for why the UBFU will be

monitored at one location, but not the other.

POC wells M54-LBF (500-750 feet perforations) and O13-O (770-1393 feet

perforations) are perforated across very large intervals (270 feet for M54-LBF and 623

feet for O13-O). It is unclear where the pump will be placed in these wells and which

specific zones will be monitored. As Curis has demonstrated in their explanation of the

POC Well P49-O sulfate exceedance, a pump setting difference of only 50 feet can result

in a change in sulfate concentrations from 1,320 mg/L to 99 mg/L. ADEQ should

require Curis to specify where the pumps will be set and what depths will be monitored

in the POC wells. In any event, it is apparent that no matter where the pumps will be

placed in the POC wells, there will be large zones that will not be adequately

monitored.

The ‚potentially down-gradient‛ POC wells M23-UBF (210-250 feet

perforations), M15-GU (554-594 feet perforations), M14GL (778-838 feet perforations),

and M22-O (932-1130 feet perforations) with the exception of M22-O, have smaller

perforated intervals. There are, however, relatively large gaps in coverage between the

193 See Temporary Application at Figure 7-2.

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perforated intervals in those wells. For instance, there is a 304 feet gap between the

UBFU and the LBFU in POC wells M23-UBF and M15GU, and a 184 feet gap in the

LBFU in POC wells M15GU and M14GL. As noted above, Curis should be required to

specify at what depths the pumps will be placed and based on the pumping and

sampling techniques utilized, and what zones will be monitored. Again the differences

in the perforated intervals between the two clusters of POC monitoring wells

demonstrate the inconsistencies of Curis’s proposed monitoring plan.

The two POC well clusters discussed above are located in the direction of the

regional groundwater gradient (northwest) from the Commercial PTF well field. No

POC wells are located to the west or southwest of the well field. Although Curis

justifies its POC well locations based on a series of contour maps depicting

groundwater flow in the Oxide Zone,194 a review of those figures for the Oxide Zone

reveals only limited data points supporting each contour map, and in some cases, no

data points for the entire southwest third of the study area. Two of the figures, Figures

14C-32 and 14C-47, demonstrate westerly groundwater flow direction in the Oxide

Zone. Because of the hydraulic connection between the LBFU and Oxide Zones, and

the close proximity of the LBFU to the injection zone within the Oxide Zone, figures

depicting groundwater flow direction within the LBFU should also be considered when

determining appropriate POC well locations. LBFU flow contour maps demonstrate

three periods (Figures 14C-40, 14C-42, and 14C-47) where flow direction was to the west

or southwest.

Based on the available data, it is safe to say that the groundwater flow gradient is

not toward the northeast, east, or southeast. However, definitive conclusions of

subsurface flow direction toward the west, northwest, or southwest cannot be made

using the very limited data presented by Curis.

Flow direction can be affected by pumping from nearby off-site wells. As

observed in the aerial photographs included in the contour maps, active agricultural

activity is apparent southwest of the Commercial PTF site. Review of ADWR records

shows extensive pumping occurred in several wells located southwest of the site over

the past several years. The rate and timing of off-site pumping from the individual

194 Temporary Application at Figures 14C-32 through 14C-47.

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wells would most likely impact gradient changes that could result in flow toward the

west and southwest from the Commercial PTF site. Although peak pumping rates

would likely occur during the growing season and the warmer months of the year, all of

the contour maps that Curis relies upon to determine locations for POC wells are from

data collected primarily in January and February, times when off-site pumping

demands would be at their lowest and would influence subsurface flow patterns the

least. Curis should be required to use year-long data to evaluate groundwater flow

patterns.

ADEQ should require Curis to appropriately locate, design, and operate the POC

wells to ensure protection of the drinking water aquifer. And if the Commercial PTF is

truly intended to be a pilot then even more POC wells, sampling and data should be

required to prove up Curis’s theories prior to commercial operations. Wells should

include the ability to conduct multi-level, multi-port sampling near and just outside the

injection and extraction well field. In order to produce representative data that can be

used to truly protect the drinking water aquifer, Curis should be required to sample

wells at the same level of ongoing injection. As demonstrated by Curis’s responses to

the recent exceedances in POC well P49-O, proper placement of the pump sampling

intake is important. To effectively monitor groundwater downgradient of the

Commercial PTF well field, the POC wells should be capable of monitoring discrete

zones throughout the entire injection intervals. As currently proposed, Curis’s POC

wells are essentially worthless because they are inadequate in location, number and

depth.

5.2 Proper ALs, AQLs, & Narrative Standards Should Be Established

To Protect the Aquifer for Drinking Water Uses.

Curis must demonstrate that the Commercial PTF facility will not cause or

contribute to a violation of an Arizona Water Quality Standard (AWQS) in groundwater

or, if a specific standard is already exceeded, that the facility will not further degrade

groundwater quality.195 ADEQ may prescribe discharge limitations in individual APP

permits to prevent contamination of the drinking water supply by Curis’s mining

195 Ariz. Admin. Code § R18-9-A202(A)(8).

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activities.196 A discharge limitation is statutorily defined to mean ‚any restrictions,

prohibition, limitation or criteria established by the director, through a rule, permit or

order, on quantities, rates, concentrations, combinations, toxicity and characteristics of

pollutants.197

Once groundwater contamination occurs, it can be difficult to clean up. The

Legislature, therefore, provided a means for ADEQ to require action to prevent or

mitigate contamination before AWQSs are violated. Alert levels (ALs) are groundwater

quality standards established in an individual permit that serve as an early warning of a

potential violation of a permit condition related to BADCT or the discharge of a

pollutant to groundwater.198 ADEQ may prescribe ALs for the Commercial PTF that,

when exceeded, trigger contingency actions or permit changes to prevent further

pollution.199 ALs must be determined based upon site-specific conditions or other

relevant information. ALs may be specified at a location appropriate for the discharge

activity, considering the discharge’s physical, chemical, and biological characteristics,

the treatment process, and site-specific conditions.200 An Aquifer Quality Limit (AQL)

is a groundwater quality standard measured at a Point of Compliance for the facility.

An AQL is equivalent either to an AWQS or, if the AWQS is already exceeded, the

ambient water quality for that pollutant.201 ADEQ may set AQLs in individual permits

to ensure that the facility continues to meet required groundwater standards.202

Curis’s approach to ALs and AQLs has been to raise them as high as possible or

to rely on 15-year old standards originally set for BHP’s old project. Curis has even

proposed that it be allowed to pollute the aquifer to levels higher than federal drinking

water standards. The aquifer into which Curis will be injecting acid mining solutions

currently demonstrates excellent groundwater quality. Curis should not be allowed to

degrade Florence’s drinking water supply through its casual approach to these

196 Ariz. Rev. Stat. § 49-243(K).

197 Ariz. Rev. Stat. § 49-201(14).

198 Ariz. Admin. Code § R18-9-101(2).

199 Ariz. Rev. Stat. § 49-243(K).

200 Ariz. Admin. Code § R18-9-A205(A).

201 Ariz. Admin. Code § R18-9-101(3).

202 Ariz. Admin. Code § R18-9-A205(C).

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important groundwater protection standards. As stated previously, if the POC wells

are located to far from the Commercial PTF well field, the early warning measures that

ALs are designed to provide are completely useless.

5.2.1 Curis’s proposed arsenic limit pushes the cost of SDWA-mandated

treatment downstream to drinking water providers.

Curis has proposed that it be held to an arsenic standard of 50 ppb, five times the

current Maximum Contaminant Limit (MCL) under the Safe Drinking Water Act, at

four existing POC wells.203 This is not because of background concentrations—

groundwater in the area has nothing near these concentrations of arsenic. Rather, we

believe Curis’s request is based upon the fact that ADEQ has never revised the AWQS

for arsenic to make it consistent with the federal MCL, despite a statutory requirement

to do so. By proposing to keep the old BHP ALs and AQLs at these four POC wells,

Curis is hoping to avoid the new, more stringent standard for arsenic and reduce

groundwater cleanup costs for the Commercial PTF.

Curis knows that the arsenic AWQS exceeds federally-mandated standards. Yet

it chose to ignore the risk to local groundwater supplies in favor of a more relaxed

standard in order to save money. We trust that ADEQ will not agree to a 50 ppb arsenic

standard, but will hold Curis to the federal MCL. Water providers throughout Arizona

were required to undertake expensive improvements to their systems several years ago

to meet the new arsenic standard. Curis should not be permitted to avoid the same

requirement and thereby push the cost of arsenic treatment off onto downgradient

water users.

5.2.2 Curis’s sulfate proposal is inconsistent with the Safe Drinking Water

Act’s Secondary MCL for sulfate and the concomitant public health

risks of nearby sensitive populations.

Water’s smell, taste, and color are affected at 250 mg/L sulfate, one third the level

allowed under BHP’s old APP permit. Sulfate in water at levels above 250 mg/L,

especially combined with high Total Dissolved Solvents, also can cause gastronomic

203 Temporary Application at, Attachment 15, Table 15.4 (March 1, 2012).

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problems in sensitive populations, such as infants, transient populations, and new

residents.204 Based on these considerations, the Environmental Protection Agency

(‚EPA‛) has set the Secondary Maximum Contaminant Level (SMCL) for sulfate in

drinking water at 250 mg/L.205

The 1997 APP permit effectively allowed BHP to create a plume of sulfate in the

groundwater beneath this mine site that would have rendered that water unusable for

drinking water purposes. Once hydraulic control was stopped, that plume would have

begun to move downgradient. Sulfate dissipates very little as it moves through an

aquifer, is persistent in groundwater for decades, is difficult and expensive to remove

from drinking water sources, and can interfere with treatment for other contaminants,

such as arsenic.

Given that BHP owned all of the property two to three miles downgradient from

the mine and that no drinking water wells existed in the area, it may have been

acceptable in 1997 to allow creation of a sulfate plume in this aquifer. But it is not

acceptable today. Residential development now surrounds the mine area, drinking

water wells have been installed downgradient, and more wells will be needed in the

foreseeable future. Pulte Del Webb’s Anthem Community directly downgradient of the

Mine consists of two populations–a retirement community and a family community,

both of which are encompassed within the sulfate sensitive populations recognized by

USEPA in the secondary MCL. And this is just the beginning, with many more homes

planned for the downgradient area. Whatever value there may be in mining copper at

this site, it does not justify pollution of the area’s groundwater with a sulfate plume that

will endanger downgradient drinking water supplies for decades to come.

Nevertheless, Curis has proposed to carry these same terms into its new APP

permit, but with one important change. In its application, Curis proposes that each well

204 USEPA, National Secondary Drinking Water Regulations, Final Rule, 44 Fed. Reg. 42195, 42201

(July 19, 1979); Announcement of Regulatory Determinations for Priority Contaminants on the

Drinking Water Contaminant Candidate List, 68 Fed. Reg. 42898, 42905 (July 18, 2003); Drinking

Water Advisory: Consumer Acceptability Advice and Health Effects Analysis on Sulfate, EPA 822-R-03-

007 (February 2003).

205 44 Fed. Reg. 42195 (July 19, 1979).

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in a mine block be treated separately. As an individual well reaches 750 mg/L, rinsing

and hydraulic control at that well would cease.206 One by one, wells would be shut

down within a mine block that may contain up to 600 wells. Some of those 600 wells

might take years to reach the trigger sulfate level. But Curis is proposing to only

sample for contaminant rebound after the very last well has reached the trigger level.

Under that scenario, contaminant rebound could occur unnoticed in the first wells to be

shut down, with contaminants escaping the mining zone for years before rebound

sampling occurred. Only after the last well in a block reaches the trigger level would

Curis notice the contamination and be required to take action. By that time, serious

damage to the aquifer beyond the mine block could already have been done.

Nothing about this proposal makes sense under today’s conditions in the Town

of Florence. Other mines in Arizona, such as the Sierrita and Bisbee copper mines, are

required to provide replacement water supplies when sulfate in groundwater exceeds

250 mg/L. The Town of Florence and its residents deserve no less protection.

Permitting Curis to endanger drinking water supplies through the creation of a plume

of sulfate is contrary to the purposes of the APP program and the Safe Drinking Water

Act. Sulfate should not be a trigger for the measurement of other contaminants in the

aquifer, it should be treated as a significant drinking water contaminant that must be

reduced below 200 parts per million before rinsing and hydraulic control in a mine

block can cease.

5.2.3 A Sulfate Standard of 750 mg/L Allows Curis to Pass Groundwater

Treatment Costs Along to Downgradient Water Users.

Permitting Curis to create a sulfate plume at concentrations up to 750 mg/L will

push treatment costs off on downgradient water providers and their customers. It is

much more costly to repair and maintain arsenic treatment systems when the water

supply has sulfate levels above 200 mg/L. ADEQ has recognized that the thresholds at

which the interferences from sulfate and TDS begin to take effect occur at 200 mg/L for

sulfate and 750 mg/L for TDS.207 Therefore, the sulfate concentrations generated by

206 Curis Resources, UIC Permit Application: Table of Existing and Proposed Requirements of UIC

Permit No. AZ3900001, at 22 (March 25, 2011).

207 Arizona Department of Environmental Quality, Arsenic Master Plan, at 3-3 (February 2003).

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Curis’s mining activities will undoubtedly affect the ability of Johnson Utilities and

other downgradient water systems to effectively treat for arsenic and comply with

federal drinking water standards. Water providers and their customers should not

have to bear higher treatment costs when a reasonable narrative standard can be

established that will protect production wells, avoid higher arsenic treatment costs, and

keep treatment costs where they belong—with Curis. The AQL for sulfate in Curis’s

permit should be set at 200 mg/L or below not only to protect public health and the

aesthetic qualities of drinking water consumed by the public, but also to prevent sulfate

and TDS interference with expensive arsenic treatment systems.

Curis is required to monitor sulfate levels in groundwater after it closes a mine

block, rinses the groundwater, and suspends hydraulic control. Amazingly, Curis has

proposed in its Contingency Plan that, if sulfate concentrations exceed 750 mg/L after

the suspension of hydraulic control for 30 days, it should be permitted to establish a

new permit standard for sulfate rather than take steps to reduce sulfate levels.208 This is

a common tactic used by ISL mining companies around the country when they are

unable to reduce pollutant concentrations to permit limits. Curis should not be able to

establish new indicator concentrations for sulfate, but should be required to re-establish

hydraulic control until the sulfate concentrations are reduced to acceptable levels,

through treatment and remediation if necessary.

5.2.4 ADEQ Should Establish a Narrative Sulfate Standard in the APP of

200 mg/L.

ADEQ can include narrative standards in Curis’s APP to protect ‚all current and

reasonably foreseeable future uses of the aquifer‛ with respect to non-hazardous

substances, such as sulfate.209 Given the growth that the Florence area is experiencing, it

is reasonably foreseeable that water providers will need to drill additional wells in the

area surrounding the mine in the coming years to keep up with ever-increasing

demand. The APP should establish standards and conditions that will protect not just

current groundwater uses at existing wells, but future uses and future points of

groundwater withdrawal.


209 Ariz. Rev. Stat. § 49-244(3).

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ADEQ’s own policy supports a 200 mg/L narrative standard for sulfate. ADEQ

has set forth factors to consider in establishing narrative standards, which include the

following:

1. Present or reasonably foreseeable uses of water in the aquifer;

2. Knowledge of human health-based guidance levels or some other risk-

based or use-based level for the pollutant;

3. Concentration of the pollutant in the discharge and ambient groundwater;

4. Volume of the discharge;

5. Hydrogeologic conditions; and

6. Potential fate of the pollutant in the aquifer.210

A thorough consideration of each of these factors indicates that the AL for sulfate

should be lowered. In regard to the first factor, water providers downstream of Curis

currently serve drinking water to customers that will be affected by the rising sulfate

concentration levels emanating from Curis’s mine. As Florence grows, drinking water

demands will increase substantially. This use of groundwater for drinking and other

potable uses is a reasonably foreseeable use that must be protected in a permit.211

Second, as described previously, high sulfate levels in drinking water have

known aesthetic and health impacts that warrant a lower standard. While the

secondary MCL is not legally enforceable, it does represent a guidance level that ADEQ

must consider in setting groundwater standards applicable at Curis’s POC wells.

With regard to the third factor, there is an enormous discrepancy between the

concentration of sulfate in ambient groundwater and the levels of sulfate that would be

permitted under Curis’s proposal. Sulfate concentrations in the area are generally well

below 200 mg/L and in many areas are well below 100 mg/L. To allow Curis to

210 See James F. DuBois, Substantive Policy Statement Using Narrative Aquifer Water Quality

Standards to Develop Permit Conditions for Aquifer Protection Permits, at 2 (October 3, 2003).

211 Id. (‚if there is a nearby community that is growing in a manner that will likely require use of

the aquifer in the [discharge impact area], then a current or reasonably foreseeable future use of

the aquifer is presumed.‛).

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generate a plume of sulfate with concentrations several times ambient levels is, simply

put, to legalize pollution of the drinking water supply.

Next, because Curis proposes to inject sulfuric acid into the aquifer, Curis’s

mining will generate enormous volumes of sulfate. Curis plans to continue operations

for at least 20 years, although it is readily foreseeable that mining could last much

longer. Therefore, the volume of sulfate that is placed into the aquifer will steadily

increase over the next several decades, warranting increased protections in the APP.

The fifth factor is especially significant. Curis is proposing to mine this property

because it contains sulfide ore. That ore necessarily generates large quantities of sulfate.

The migration of sulfate plumes into Florence’s drinking water supply could be

devastating. A narrative standard for sulfate must be set with ALs low enough to give

early warning of future migration and provide time to resolve the problem or find

alternative supplies of water before drinking water wells are impacted.

As to the final factor, sulfate does not naturally degrade in the aquifer. Given

that technological solutions to treat sulfate contamination are limited and expensive,

dispersion of the plume likely is the only way that sulfate levels will decrease.

Dispersion generally is a slow process, but it is likely impossible while Curis continues

to operate and generate contaminants that will be released into the aquifer. Because

Curis plans to continue operating for at least twenty years and dispersion may take

centuries, Florence and its residents cannot count on natural dispersion to reduce

sulfate levels in the aquifer.

Each of these factors argues for lower narrative standards in Curis’s APP. The

potential health and aesthetic impacts of sulfate, along with the impacts of sulfate and

TDS on arsenic treatment, also require consideration of protective narrative standards.

ADEQ should set a narrative standard for sulfate no higher than 200 mg/L to protect

Florence’s drinking water supply from Curis’s sulfate pollution.

5.2.5 Alert Levels Should Be Established for Other Pollutants Without

AWQSs.

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ADEQ has noted that Curis needed to calculate and propose ALs for constituents

without AWQS. Pollutants mentioned by ADEQ included sulfate, discussed

previously, TDS, and radiochemicals.212 ADEQ should hold Curis to these

requirements. Proper ALs for radiochemicals, including uranium, are vital given the

site’s history of high radionuclide levels, the 1999 EPA TENORM report and the fact

that acidic in-situ solutions are used to extract radiochemicals. Curis also should be

required to establish an AL for pH, given indications that restoration of groundwater

pH may be problematic. ALS should also be required for magnesium, sodium, and

aluminum since these constituents usually build up in solution and are highly soluble

when exposed to Curis’s acid mining solutions.

5.3 Curis’s Proposal for Monitoring of Pollutants Is Offensively

Inadequate.

Curis has portrayed the Commercial PTF as a pilot test designed, at least in part,

to develop data in support of better environmental compliance. But in its Temporary

APP application, Curis proposed to sample for Level 2 contaminants (which include

heavy metals and radiochemicals) only once every two years. This is a ridiculous

proposal for a facility that supposedly will operate for just 14 months. ADEQ rejected

this proposal and ‚requested‛ that Curis conduct Level 2 parameter sampling on a

quarterly basis.213 Curis responded to that request with a proposal to sample for Level 2

contaminants once a year. It is not clear whether ADEQ will require Curis to conduct

quarterly sampling. But because the Commercial PTF is supposedly designed to

answer the significant questions that exist about the environmental impacts of this

mine, ADEQ (and presumably Curis) should not want to skimp on developing data.

Instead one would think that the goal would be to strive to more fully understand the

potential implications of the mine operations by increasing the data developed in the

Commercial PTF. For this reason, ADEQ should require full Level 2 contaminant

sampling on at least a quarterly basis.

212 May Deficiency Letter, Item 10; draft letter.

213 ADEQ September Deficiency Letter at 21-22 (HD ¶75).

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5.4 ADEQ Should Require Curis to Provide Notice of Exceedances of

APP Standards to the Public.

Curis will have to notify ADEQ and USEPA of exceedances of AWQSs, AQLs and

ALs. But such exceedances also should trigger notice to the public, including adjacent

landowners, the Town of Florence, and Johnson Utilities. It is well within ADEQ’s

discretion to require such public notice through a newspaper or the Internet.

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6 The BHP Pilot Raised More Questions Than It Provided

Answers.

Don’t buy Into Curis’s contention that the previous BHP Pilot demonstrates that

Curis’s Commercial PTF will comply with AWQS at the POC. Despite questions from

both EPA and ADEQ, Curis continues to assert that the previous BHP Pilot test of the

late 1990’s somehow proves that Curis can operate its proposed Commercial PTF and

commercial operations free of risk to the drinking water aquifer. 214 ADEQ should be

very wary because other information demonstrates that BHP’s Pilot was not as

successful as Curis would lead you to believe. Curis’s sweeping conclusions and

assertions about the previous pilot effort do not appear to be based upon a thorough

evaluation of detailed data generated from the previous pilot. Indeed, if the BHP

testing were as successful as Curis asserts, it seems that the data would have been

presented publicly as proof that ISL is commercially feasible at this site, but that has not

occurred. And despite Curis’s assertions, historical groundwater data from the BHP

Pilot and up to the present demonstrate that water quality has indeed been impaired by

the BHP Pilot Test. Importantly, it should be noted that the BHP test was at a scale that

is roughly 70 times less than the proposed commercial scale operation and was

operated for only 90 days versus a proposed 20 year mine life.

It appears that Curis has based their conclusion that hydraulic control was

successfully demonstrated solely on the BHP letter report to ADEQ dated April 6, 1998.

Curis indicated that ‚*h+igher water levels and lower electrical conductivities at the

observation wells than at the recovery wells were deemed to demonstrate hydraulic

control.‛215 A detailed review of the April 6, 1998 document reveals a few serious

concerns with the information provided. As was discussed earlier, despite Curis’s

assertions of a successful BHP Pilot, the data reveals that over a two to three day period

(November 8, 1997 to November 10, 1997), hydraulic control was not adequately

maintained between recovery and observation well pair BHP5/OWB4 with a gradient

differential (flow in the wrong direction) documented during a 12-hour period that was

greater than 48 feet. Also, it appears that hydraulic control was only marginally

214 See, e.g., Temporary Application at §12.2.2.1.

215 Temporary Application at § 10A.2.3.

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maintained at this location with a relatively flat groundwater gradient documented

from November 8, 1997 to November 18, 1997.

Another concern revealed by a review of the data is the methodology for

measuring conductivity values in the observation wells appeared to be different than

that used for the recovery wells, which likely results in data that could not be

adequately compared. BHP’s recovery and observation well sampling method was

described as follows:

The data for electrical conductivity was measured by hand. The

samples were taken by two methods. The wells labeled as BHP2,

BHP3, BHP4, and BHP5 were continuously running pumping

wells. < Observation wells OWB1, OWB3, OWB4, and OWB5 did

not have pumps in them during the test. These wells were sampled

using a sample baler [sic] with a small pump attached to guarantee

a good sample. The procedure for this sampling was to turn the

pump on for five minutes and then let the sample collect for

another two minutes before retrieving the baler [sic].216

This description suggests that zone specific samples were collected from the

observation wells at depths that may not have been the same as the samples being

collected from the recovery wells, which may have represented deeper samples. If the

depth placement of the bailers used in the observation wells was different than the

depth placement of the pumps in the recovery wells, a direct comparison of hydraulic

conductivity data from the observation well and recovery well pairs cannot be made as

it is known that measured conductivity results can vary widely at different depths even

from the same well. Further, this would call into question Curis’s conclusions that

hydraulic control has been effectively maintained. Curis should be required to

demonstrate and document the depths where the samples from the observation wells

and recovery wells were collected during the BHP pilot test.

Done properly, conductivity value comparison can be useful to determining

whether hydraulic control is being maintained. Interestingly, Curis has not proposed to

216 BHP Letter to Ms. Julie Collins, ADEQ (April 6, 1998).

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use this method to evaluate hydraulic control during Commercial PTF operations.

Curis should be required to monitor for hydraulic control in more than one way to

prove up its concept of hydraulic control for the Commercial PTF.

Additionally, although Curis states that a final report on chemical analyses from

the BHP pilot was never performed, there was apparently a Draft Field Test Report

prepared and revised in October 1999. This report is not in agency files but Curis likely

has it in their possession. It apparently discusses major disparities between the data

that was produced during the field tests and the data used to justify the economic

viability of the project during the permitting of the facility in 1996 and 1997. And it

further supposedly discussed the need to conduct additional study including a field-

scale leach test run to completion that would take years.217 It also apparently noted that

tests completed by BHP indicated that a significant decrease in pH could occur if

leaching of the deposit proceeded as authorized by the permit and efforts to increase

copper recovery would further exacerbate the low pH problem and could mobilize

heavy metals and radiological elements. Despite public records requests to ADEQ,

ASLD, and EPA, the draft report cannot be located. It has apparently vanished. Not

one of these agencies has a copy of this draft report. It is apparent, however, that Curis

as a Merrill successor does. ADEQ should require Curis to provide it with a full and

complete copy of the draft evaluation for the agency’s consideration in assessing Curis’s

reliance on the BHP pilot.

6.1 Groundwater Exceedances Should Not Be Ignored.

6.1.1 Present-Day Groundwater Exceedances.

Recent groundwater exceedances and Curis’s responses demonstrate that the

area’s geophysical environment is extremely complex and, despite assertions to the

contrary, is not well understood by Curis. Groundwater exceedances were experienced

very recently in just December 2011 and January 2012, requiring notification and

explanation to both USEPA and ADEQ. Curis's recent water quality monitoring data

from P49-0 – a monitoring well perforated in the oxide bedrock zone into which BHP

injected acidic solution – demonstrates significant exceedances of alert levels for sulfate,

217 Merrill Mining Ranch Letter to Mohave Resources, Inc. (Nov. 21, 2006).

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magnesium, and total dissolved solids. Exceedances of the magnitude reported by

Curis in wells expressly designated to monitor groundwater conditions resulting from

the previous pilot test create doubt as to the effectiveness of BHP’s hydraulic control

efforts of the late 1990’s. Explanations proffered by Curis appear to conflict with past

data it has presented regarding the project’s wells and underlying geology. Their

explanations simply do not add up, instead eliciting a plethora of additional questions

about the area’s hydrogeology, the true state of groundwater quality after the 1997 pilot

project, and whether anyone can truly control the underground movement of injected

acidic solutions.

6.1.1.1 The Data

On December 5, 2011 as part of a required quarterly monitoring program, Curis

collected a sample from monitor well P49-O. Sample analysis revealed significant

exceedances of the established ALs for magnesium (Mg), total dissolved solids (TDS),

and sulfate (SO4). Follow-up sampling on January 4, 2012 confirmed the previous

results. Data from the recent exceedances as well as the mean values of 16 rounds of

previous sampling are shown in the following table.

P49-O Groundwater Monitoring Results

Sample Date

Magnesium

(mg/L)

Sulfate

(mg/L)

Fluoride

(mg/L)

TDS

(mg/L)

1996-19981 3.62 1022 0.952 4722

12/5/11 15 1,280 NI3 2,000

01/4/12 15 1,320 <0.4 2,000

Alert Level

6.2

181 1.9 801

1 = 12 samples were collected in 1996 and four samples were collected from 1997 to 1998.

2 = Results shown are mean values of the 16 sample results collected from 1996-1998.

3 = Data not included.

Bold = Result is greater than the established Alert Level.

As reflected in the table above, previous sample results from the initial 12 rounds

conducted in 1996 prior to the BHP Pilot and from 1997 and 1998, show concentrations

of sulfate, magnesium, and TDS that are orders of magnitude lower than the recent

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results. These historic data were used to set the AL for the indicator parameters. The

mean concentration of sulfate from those sampling events (102 mg/L) is roughly 13

times lower than the confirmation sampling result recently measured. A copy of a data

table summarizing the laboratory results of the previous sampling is included as

Attachment X.

6.1.1.2 Well P49-O Specifics

A review of information pertaining to well P49-O indicates that the well is

perforated exclusively within the oxide zone. P49-O is located near the southwest

corner of the in-situ copper recovery (ISCR) area, which is also where the steep contact

between the LBFU and Oxide Zone exists. A figure showing the location of well P49-O

can be seen in Attachment Y. Although Curis attempted to rationalize that the

exceedances resulted from P49-O’s well screen extension into the deeper sulfide portion

of the deposit, such an argument is not supported by documentation from the

installation of P49-O. Review of those data indicates that the well itself does not

penetrate the sulfide zone. In addition to the well installation data, relevant lithological

and geophysical logs do not support Curis’s claim that P49-O extends into the sulfide

zone. Instead, the lithological log and geophysical logs developed for P49-O that

alternating layers of quartz-monzonite-porphyry and granodiorite-porphyry

encountered below the LBFU deposits at a depth from 700 feet bls to the total depth of

the borehole at 1288 feet bls. There is no evidence in the lithological log, geophysical

logs, or Brown and Caldwell well summary to support Curis’s re-interpretation of the

data, a re-interpretation which is integral to Curis’s explanation of the sulfate AL

exceedance in well P49-O. See tables in Attachment X and P49-O well diagrams, design,

construction, and lithology information in Attachment Z.

6.1.1.3 Groundwater Flow Direction

Although Curis attempted to explain away these high readings as unrelated to

the BHP Pilot by arguing that P49-O is located cross-gradient and that other indicator

parameters demonstrated significant decreases, such arguments are inconsistent with

previous data. A groundwater contour map prepared by Brown and Caldwell for

October 2008, shows well P49-O located in a relatively downgradient direction from the

BHP Pilot area. This information, as well as knowledge that the Oxide Zone is highly

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fractured does not dispel the notion that the AL exceedances could not have been

related to the permitted mining operations.

Furthermore, sparse groundwater sampling data exists to support Curis’s

theories about groundwater flow direction. Based on the available data, it is safe to say

that the groundwater flow gradient is not towards the northeast, east, or southeast.

However, definitive conclusions of subsurface flow direction towards either the west,

northwest, or southwest cannot be made using the very limited data points (there is

only one data point for the entire southwest 1/3 of the map) included in the contour

maps for the oxide zone prepared by Brown and Caldwell (October, 2008). Also, the

available data can be interpreted to show alternate groundwater surface gradients. For

instance, reviewed review of the October 2008 Oxide Zone contour map indicates that

the ‚1269‛ elevation contour line’s location does not adequately honor the data points

represented by the wells M22-O and P49-O. Honoring those data points results in a

more representative flow pattern which shows well P49-O downgradient of the BHP

Pilot well field. See Attachment 2, Figure 1.

Flow direction can also be affected by pumping from nearby off-site wells.

Curis’s arguments appear to ignore significant pumping in the area from irrigation

wells and other sources, as if Curis was the only area groundwater user. Instead, past

groundwater elevation data supports alternate groundwater flow directions indicating

that this recent set of exceedances could have been caused by the previous BHP Pilot.

As observed on the western edge of the aerial photograph included in the contour map,

active agricultural activity is apparent west of well P49-O. Review of ADWR records

shows extensive pumping occurred in 2008 for several wells located southwest of the

Mine. See Attachment 2, Figure 1 for total volumes pumped from each of those wells.

The rate and timing of off-site pumping from the individual wells would most likely

impact gradient changes that could result in flow toward well P49-O from the BHP Pilot

area.

Regarding the alleged significant decrease in other indicator parameters, pre-

pilot tests for fluoride ranged from 0.29 to 1.3 mg/L. The confirmation sample, which is

the most current analysis, shows a non-detect level of <0.4 mg/L, a result that can hardly

be described as a significant decrease.

6.1.1.4 Sampling Methodology

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In submittals to ADEQ and EPA, Curis also tried to dismiss the exceedances as a

result of low flow sampling methodology and as analogous to ranges observed in well

M24-O. First, with respect to flow sampling methodology, it is difficult to believe that

the type of pumping system could affect a change as drastic as experienced in P49-O.

Such a result would in essence negate all of the groundwater data collected historically

for the site.

Curis’s attempt to blame groundwater exceedances on where the sampler chose

to place the pump intake within the well raises even larger concerns. It does not appear

that there is a clear rationale for the depth placement of pump equipment in the wells

used for monitoring purposes. Initially, the Grundfos pumping system was installed at

a specified, but unknown depth in P49-O. When that pumping system was replaced

with a low flow bladder system, the intake of the low flow sampling device was

inexplicably placed “at a point much deeper than that of the Grundfos submersible pump

previously used for sampling”. When the samples collected from that depth setting

returned unfavorable results, the intake of the low flow sampling device was raised 50

feet to an apparent third separate depth setting for this well.

If the depth setting for the sampling devices can affect such drastic changes in

water quality results, it is imperative that ADEQ mandate a permit condition

establishing depth settings for the equipment. Without such a requirement, it is hard to

place any confidence in data obtained from a well that has utilized three random pump

depth settings, or for that matter any well in the entire monitoring well system if the

pump depth settings are established in a completely random fashion with no clear

understanding of what is to be monitored. This point is further exacerbated by the fact

that many of the POC wells are perforated at intervals greater than 400 feet and at zones

that do not appear to correlate with the elevations where acidic solutions are being

injected. If such a relatively simple factor as pump placement can have such major

impacts on the representative nature of project samples, how can the public be assured

that Curis’s sampling efforts will accurately detect future excursions and that Curis

hasn’t just placed the pump in the wrong portion of the well?

ADEQ cannot allow Curis to determine equipment placement at will, changing

the depth whenever they get undesired results. In order to ensure representative data,

ADEQ must specify representative equipment placement within the monitoring wells.

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99

ADEQ should also require Curis to re-sample the well under the exact conditions as the

pre-pilot test for comparison purposes. Curis should also be required to perform

discrete, zone specific sampling throughout the perforated interval of the well to

investigate where the high sulfate concentrations are emanating.

6.1.1.5 Data from M24-O

Curis also attempted to justify the high readings from P49-O as consistent with

readings from another well, M24-O. The two wells are, however, not comparable. Well

M24-O, located approximately 1,200 feet away from P49-O, was used to prepare

contours for the LBFU as opposed to the Oxide Zone (see the figure provided in

Attachment 2) demonstrating that the wells are apparently perforated in different

geologic units. M24-O is reportedly installed entirely within the LBFU and does not

penetrate either the oxide zone or sulfide zone.

It is also disingenuous for Curis to claim that the higher concentrations detected

in well M24-O are representative of “pre-mining, ambient conditions” since we know that

this area is directly downgradient from Conoco’s mining activities of the 1970s.

According to public records, Conoco’s mining operations included oxide vat leaching

operations with the addition of acidic raffinate solutions and at least two unlined tailing

impoundments. Similar Arizona mining operations have impacted the subsurface

resulting in plumes of sulfate.

Curis’s argument that the relatively high concentrations detected in well M24-O

occurred by similar processes that caused the high concentrations in P49-O, namely

‚sulfide minerals or their geochemical weathering by-products‛ and ‚natural variation

in the ore body and surrounding formation‛, is not supportable. As evident in the table

below, data from M24-O over time reveals only slight increases in magnesium, sulfate,

and TDS concentrations, nowhere near the magnitude of difference observed in P49-O.

M24-O Groundwater Monitoring Results

Sample Date Magnesium

(mg/L)

Sulfate

(mg/L)

Fluoride

(mg/L)

TDS

(mg/L)

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1996-19981 11.22 7882 0.9952 1,3662

5/25/11 10 776 1.2 1,300

9/27/11 14 1,100 1.2 1,700

11/30/11 13 1,110 1.2 1,700

Alert Level

19 1,364 2.5 2,363

1 = 17 samples were collected between 1996 and 1998.

2 = Results shown are mean values of the 17 sample results collected from 1996-1998.

6.1.1.6 Health Concerns

The incredibly high sulfate levels found in Curis’s recent well data are cause for

extreme concern given the impact of sulfate contamination on sensitive populations (for

example, young children and the elderly). As you know, ADEQ imposed narrative

standards at the Sierrita Mine near Green Valley that are 20 percent of the levels seen

here (250 mg/1). That was done, in part, to prevent sulfate contamination from affecting

the health of sensitive populations downgradient. The surrounding communities in

Florence deserve no less protection from mining impacts.218

6.1.1.7 New “Pods of Sulfite Deposit” Concept

Of great concern to us is what appears to us to be a new concept not previously

accounted for by Curis in its mining proposal, namely that there are ‚pods of sulfide

minerals‛ in the area that could contribute to groundwater exceedances. Specifically,

after getting the exceedingly high results form P49-O, Curis now claims that “contact

between the oxide and sulfide portions of the ore body is gradational in nature and

does not preclude pods of sulfide minerals from occurring within the oxide zone.‛ It

cannot be denied that high concentrations of sulfate are present in P49-O, but if those

concentrations are the result of the presence of a ‚pod of sulfide minerals,‛ why has it

taken over 16 years to make this determination? Curis’s APP application fails to discuss

and account for the concept of ‚pods of sulfide minerals.‛ And if we hadn’t requested

218 See Section 5.2.2 for a more detailed discussion of the sulfate issue.

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and reviewed Curis’s recent monitoring data, no one would have ever known about

this recently discovered phenomenon of ‚pods of sulfide minerals‛. In light of this new

information, we question whether anyone has fully investigated and characterized this

concept of ‚pods of sulfide minerals‛ and how they could interact with Curis’s

proposed mine. Because Curis’s new theory makes it is apparent that the site’s

hydrogeology has not been adequately characterized, ADEQ should require Curis to

fully investigate and explain this concept and its possible interactions with proposed

injection activities. If the presence of these so-called ‚pods of sulfide minerals‛ can be

so influential to water quality results then Curis must locate, map and explain all their

occurrences. If ADEQ doesn’t require Curis to thoroughly investigate these

occurrences, then every time Curis gets a monitoring result it dislikes, Curis will simply

chalk it up to influences from a previously unknown and undocumented ‚pod of

sulfide minerals‛ in the sub-surface. Such a result is simply unacceptable.

Although Curis attempted to explain the exceedances as non-issues, their

explanations cannot withstand vigorous technical review. Instead, the recent

exceedances and Curis’s responses demonstrate that the area’s geophysical

environment is extremely complex and, despite Curis’s assertions to the contrary, is not

well understood by Curis. Because of this, we question how Curis can adequately and

fully protect the area’s groundwater from the proposed mining operation. As a result,

we request that ADEQ deny Curis’s requested permit as unable to meet the standards

at the POC as required by Arizona law.

6.1.2 Other Post-BHP Pilot Test Groundwater Exceedances.

After the Pilot Test, BHP admitted to exceeding water quality permit limits in a

report submitted to ADEQ. According to a March 1999 BHP report, quarterly

groundwater data from the pilot test revealed 26 exceedances of applicable

groundwater quality standards and ‚*n+ine of the 31 wells were reported to have had at

least one exceedance.‛219 Additionally, an independent review of a sampling of the data

associated with the BHP pilot test groundwater sampling confirmed numerous permit

limit exceedances. For example, samples from seven of the pilot’s point-of-compliance

219 BHP Letter to Mr. Greg Olsen, ADEQ regarding BHP Copper’s Florence Project (March 8,

1999).

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wells over multiple points in time demonstrated magnesium in groundwater above the

permit limits. Permit limits for total dissolved solids and for sulfate were also exceeded

in groundwater samples from the test pilot. Even after permit limits were revised to be

more lenient, various contaminants continued to exceed the new permit limits. In 2001,

well M26-O showed magnesium in groundwater exceeding permit limits. And in 2005,

groundwater in well O19-GL demonstrated high gross alpha (radiochemical) levels

exceeding both the permit limit and the Aquifer Water Quality Standard.

As in-situ leach mine operators often do, BHP either dismissed the results or

obtained more lenient permit limits. For example, in one case exceedances of water

quality standards were blamed on background levels or other ‚anomalies‛. In another

case, BHP owned up to the exceedance and identified the cause as undiscovered nearby

core holes: ‚Communication between the aquifers was determined to be the most likely

cause for exceedances observed at wells M14-GL and 049-GL. Possible avenues of

communication include open holes and defects in well seals and/or casings. < Two

open core holes (one near each well) were located and sealed.‛220 Thus, one thing the

pilot test does prove is that abandoned and unidentified core holes do permit

contaminants to escape into the groundwater, something Curis has adamantly denied

despite this and other evidence to the contrary.

Groundwater testing data also reveals potential future sulfate and fluoride

problems in three POC wells. A projection of trends associated with closure monitoring

indicates that sulfate and fluoride in three POC wells (M1-GL, M-21-UBF, and M-27-

LBF) will most likely exceed the current permit limits. Curis indicates the problem is

caused by declining groundwater levels. Curiously, another part of Curis’s application

states that there have been no such declines.221 Curis’s solution to the impending permit

limit exceedances is to propose more lenient permit limits.222 One of the wells, M1-GL,

had an original sulfate permit limit of 87 mg/l223 until the mine got a more lenient limit

220 BHP Letter regarding BHP Copper’s Florence Project to Mr. Greg Olsen, ADEQ (March 8,

1999) at 4.

221 Curis APP Application, Attachment 9.

222 Application to Amend, at Attachment 15.

223 Aquifer Protection Permit No. 101704 (1997), Table III.B at 33.

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of 109 mg/l.224 Curis now proposes to make this permit limit even more lenient to 179

mg/l.225 If mining will not impact groundwater quality, as Curis claims, why have there

been so many exceedances and permit revisions arising out of a 100-day pilot test?

ADEQ itself has raised similar questions about the BHP pilot test. In its

September Deficiency Letter on the full project, ADEQ clarified that they never issued

closure or clean closure approval of the pilot test because pH standards in groundwater

were never met.226 This is consistent with previous owners’ concerns. And the agency

questioned how Curis could restore groundwater to required water quality standards in

less than two years, as proposed in Curis’s application, when extended rinsing and

pumping after the pilot test still has not demonstrated compliance with permit limits 14

years later.227 These concerns remain unaddressed.

6.2 Radiochemical Exceedances Should Not Be Ignored.

Curis is proposing to use a uranium mining technique to mine copper at a site

where the copper ore is known to contain high levels of radiochemicals. It is

indisputable that the use of this technique at this site will mobilize radiochemicals in

groundwater and concentrate radiochemicals in mine process and waste streams. The

potential risks to human health and the environment of such mining in an area zoned

for residential and commercial uses should be self-evident. But amazingly, Curis and

its predecessors have denied that use of a uranium mining technique at this site could

possibly result in radiochemical impacts to groundwater.

ADEQ has already recognized that area groundwater may be subject to leaching

from Curis’s proposed operation. Similarly, USEPA has not only recognized but

studied and documented its concerns with radiochemical impacts associated with

Curis’s proposed in-situ mining process. A review of the administrative record

associated with the Mine site reveals a history of repeated high levels of radiochemicals

224 Aquifer Protection Permit No. 101704 (revised 2000), Table III.B at 32.

225 Application to Amend, at Attachment 15.

226 ADEQ Comprehensive Request for Additional Information with Suspension (Sept. 7, 2011) at

19.

227Id. at 20.

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in groundwater with nothing but denials from the mine company. ADEQ should not

give Curis a pass on such a serious issue. Your agency has a duty to protect the public

from these contaminants. At a minimum, additional investigation of potential

radiochemical impacts is needed before a permit is issued. In addition, more stringent

sampling for radiochemicals should be a major component of the Pilot Project. Finally,

Curis should be required to provide a reasoned and detailed plan for addressing

radiochemical contamination in groundwater, impoundment pond water and

sediments, raffinate and process streams, and soils.

6.2.1 Arizona Copper Mines Generally Mobilize Radiochemicals in

Groundwater and Concentrate Radiochemicals in Process and Waste

Streams.

In Arizona, radiochemicals—primarily uranium and thorium—often are found

in or near porphyry copper deposits. The activities involved in mining the copper ore

can concentrate radiochemicals and mobilize them in the environment:

The data show that dump leaching operations and solvent extraction-

electrowinning procedures, as well as the practice of recycling raffinate at

copper mines, may extract and concentrate soluble radioactive materials.

The results show increases of up to two orders of magnitude over

background levels for all radiochemicals tested except Rn-222.228

The concentration of radiochemicals in mining process and waste streams is known as

TENORM—Technologically Enhanced Naturally Occurring Radioactive Materials.

The presence of uranium in porphyry copper deposits is such that at least two

copper mines in Arizona—the Copper Queen mine in Bisbee and Twin Buttes mine in

Sauharita—have operated commercial uranium recovery facilities in conjunction with

copper mining. At Twin Buttes, a uranium recovery unit operated from approximately

1980 to 1986, extracting uranium from pregnant leach solutions before the solutions

were sent to the solvent extraction plant for copper recovery. In 1997, Cyprus Sierrita

228 USEPA, Technologically Enhanced Naturally Occurring Radioactive Materials in the Southwestern

Copper Belt of Arizona, at iii (October 1999).

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Corporation submitted groundwater monitoring data to ADEQ in support of an APP

application. That data indicated that Gross Alpha and Gross Beta concentrations in

groundwater downgradient of the mine processing areas were three to four times

higher than background concentrations. Total uranium concentrations were five to

thirteen times higher than background.229

But even where uranium processing is not conducted, the concentration and

mobilization of radiochemicals by copper extraction and beneficiation has the potential

to contaminate groundwater, surface water, and soils. USEPA’s study of copper mining

in Arizona clearly demonstrates that copper mines across the State have contaminated

groundwater and surface water with radiochemicals at levels far in excess of

background concentrations and often exceeding federal and state drinking water

standards:

At Cyprus Bagdad mine, 64 miles west of Prescott, concentrations of

radiochemicals in excess of federal and state standards were found in

groundwater and surface water during testing in the early 1990s. As Curis

has done here, Cyprus Bagdad denied that its mining was to blame for high

concentrations of radiochemicals in groundwater, arguing that high

background concentrations and the existence of a clay layer beneath channel

sediments was the source of the readings. USEPA believed that further

investigation was needed to resolve the issue.230

At New Cornelia Mine in Ajo, Freeport McMoran found high concentrations

of radiochemicals in monitoring wells sampled in 1997. Nine wells contained

uranium, radon and other radiochemicals at levels exceeding federal and

state standards. Freeport blamed the readings on inaccurate data.231

At BHP’s Pinto Valley Mine, which is part of a large WQARF site, high

radiochemical levels were found in 1996 data from compliance monitoring

wells. All eight of the open pit dewatering wells exceeded one or more

229 Id. at 26-28.

230 Id. at 33-35.

231 Id. at 43.

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radiochemical standards. USEPA concluded that ‚the data confirm that

TENORM is present in the ore at the Pinto Valley mine and that it has

leached, in concentrations above federal standards and state guidelines, into

the groundwater.‛232

At Freeport McMoran’s Copper Queen mine in Bisbee, a plume of

contaminated groundwater extends from the mine tailings area over seven

square miles. The plume already has contaminated private wells and

threatens production wells in Naco and Bisbee. Freeport McMoran was

forced to begin supplying bottled water to some local residents years ago. In

1991 sampling, three of four groundwater samples contained radiochemicals

at concentrations exceeding federal and state standards. Subsequent

sampling confirmed radiochemical concentrations in violation of water

quality standards. Wells within the plume that were screened within the

Basin Fill deposits south of the tailings impoundments contained U-238 at

concentrations up to 80 times higher than background, U-234 at

concentrations up to 30 times higher than background, and alpha

concentrations up to 20 times higher than background.233

At Freeport McMoran’s Morenci mine, 1995 sampling indicated that gross

alpha or gross beta concentrations exceeded drinking water standards in

fourteen monitoring wells. Sampling of process and waste streams at the

mine indicated that 42 different samples contained radiochemicals at levels

exceeding federal or state standards. Gross alpha and gross beta

concentrations were sometimes hundreds of times higher than applicable

standards, clearly indicating that mining activity was concentrating

radiochemicals in process and waste streams, including the raffinate being

recycled into the leach circuit.234

This brief summary of just a few of Arizona’s copper mines clearly indicates that copper

mining can and often does concentrate radiochemicals in groundwater and surface

232 Id. at 46.

233 Id. at 47-50.

234 Id. at 59-64.

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water. In many cases across the state, concentrations of radiochemicals are high enough

to render water supplies unsuitable for drinking without treatment. To our knowledge,

no studies have been conducted to measure the effect of these contaminants on human

health and the environment through other means, such as the off-gassing of radon in

residential areas, potential air contamination from evaporation ponds and wastewater

impoundments, air-borne contaminants in dust from tailings and waste piles, and other

means.

6.2.2 Curis’s ISL Mining Will Concentrate and Leach Naturally Occurring

Uranium Into the Aquifer.

Consistent with copper mines across the State, radiochemicals are readily found

in geologic formations beneath Curis’s property. A 2004 report, authored by Curis’s

current consultants, confirmed that site tests ‚indicate that leachate from the quartz

monzonite and granodiorite is highly enriched in uranium and radium-226, and

correspondingly, both display high counts of gross alpha.‛ Curis’s consultants

conclude that ‚*i+t is therefore expected that the concentrations of gross alpha would be

high and variable in the test wells.‛235

Concentrations of radiochemicals at this site are significant enough that they may

have prompted interest in uranium exploration and mining. According to an ADEQ

comment during BHP’s previous APP process, a records review revealed a Conoco

interoffice communication showing ‚a company named UOCO had approached

Conoco about the possibility of leasing the Florence facilities to conduct small-scale

uranium vat leaching operations.‛ Also according to ADEQ, the review revealed that

‚a 5-gallon container marked ‘uranium leach liquor’ was found in the metallurgical

laboratory during the facility inspection.‛ Because of this history, ADEQ told BHP that

it needed to ensure prior to closure a complete characterization and detailed closure

plan for the site’s evaporation ponds.236 BHP assured ADEQ that they could find no

records indicating that Conoco ever used or permitted anyone to use the site for

235 Brown and Caldwell, Proposed Cessation of Hydraulic Control at the Florence Project In-Situ

Test Field (April 21, 2004) at 5-4.

236 BHP Letter to ADEQ (October 9, 1996), Tab 1, Response to ADEQ Comments issued

September 30, 1996 at 7.

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radiochemical testing and explained that upon discovery, the referenced container was

empty.237

Regardless of whether uranium mining was ever tested or conducted at the site,

this correspondence indicates that there is enough uranium present in soils at the site to

generate interest in such mining. This, in turn, supports our concern that

radiochemicals are present in sufficient quantities at the Curis site that acid leaching

could concentrate and mobilize radioactive materials, leading to contamination of the

drinking water aquifer by uranium, radium, and other radiochemicals. We also are

concerned that no attention has been given to potential concentrations of

radiochemicals in the impoundment pond water and sediments. The risks associated

with concentrations of radiochemicals in pond sediments and other waste streams

should be evaluated and addressed as a permit requirement.

USEPA has demonstrated that ISL mining at the Curis site will leach these

radiochemicals into groundwater:

In January of 1996, BHP (Magma) conducted a column leach test to

characterize the leachability of the mineralized zone and determine the

chemical composition of the resultant PLS. Samples of ore-bearing quartz

monzonite and granodiorite were leached for 58 days with 10 liters of

sulfuric acid and maintained in a closed system at a pH of 1.5 to 1.7. The

PLS was analyzed for common ions, metals and radiochemicals. The TDS

and sulfate concentration at the end of the test was 26000 to 37000 mg/L

for the quartz monzonite and 18000 to 23000 mg/L for the granodiorite.

The gross alpha and beta activities for the quartz monzonite were 8649

and 3683 pCi/L, respectively. Similarly, the gross alpha and beta activities

for the granodiorite were 897 and 612 pCi/L, respectively. The Ra-226

concentration of both samples was 33.6 pCi/L for the quartz monzonite

and 19.5 pCi/L for the granodiorite. The total uranium, U-234, U-235, U-

237 Id.

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238 for the quartz monzonite were 4362, 1745, 598, and 1611 pCi/L and for

the granodiorite 0.835, 254, 11.6, and 248 pCi/L, respectively (Table 18).238

These radiochemical concentrations are up to five hundred times higher than drinking

water standards. Of course, these concentrations do not reflect the impact of proposed

groundwater reclamation efforts on radiochemical concentrations after mining is

complete. BHP simulated that effort as well:

Subsequently, the raffinate from the PLS was recirculated into the leach

system for another 19 days. Then the samples were drained and washed

with groundwater for another 14 days in an open system. At the end of

the wash test, the solution was tested for radiochemicals. The gross alpha

and beta activities for the quartz monzonite and granodiorite were

reduced to 11 and 3 (alpha) and <8 and <8 (beta) pCi/L for both the quartz

monzonite and granodiorite. The Ra-226 and Ra-228 concentration was

also reduced in both samples. The total uranium, U-234, and U-238 were

10, 27.3, 20.7 and 1.2, 6.8, and 4.82 pCi/L, respectively (Magma, 1/1996).

The analytic results are shown in Table 18 (Magma, 1/1996). In all cases

the quartz monzonite showed higher levels of radiochemicals than the

granodiorite. The range of background levels alpha and beta activity and

Ra-222 are shown at the bottom of the Table 18.239

Thus, the BHP column leach tests showed that radiochemical concentrations could be

reduced in groundwater through rinsing. But the rinse test did not reduce gross alpha,

radium or radon concentrations to background levels. Furthermore, BHP’s column

leach test appears to have simulated a groundwater rinsing program that was much

more extensive than the one proposed by Curis. We have serious concerns that any

groundwater rinsing program, no matter how extensive, will not be able to reduce

radiochemicals to background levels. It is even more unlikely that the extremely

limited rinse program proposed by Curis will eliminate radiochemical impacts to the

aquifer.

238 USEPA, Technologically Enhanced Naturally Occurring Radioactive Materials in the Southwestern

Copper Belt of Arizona, at 31 (October 1999).

239 Id.

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6.2.3 Curis’s ISL Mining Process Is Used Around the World to Mine

Naturally Occurring Uranium.

ISL mining is used world-wide to extract uranium. It is indisputable that the

injection of alkaline or acid mining solutions into ore bodies will dissolve

radiochemicals from soil and rock, mobilizing those radiochemicals in groundwater

aquifers. This is exactly what makes ISL mining such a popular technique for uranium

mining. The use of this same technique at Curis’s site—a site known to contain high

levels of radiochemicals—will absolutely mobilize radiochemicals in groundwater and

concentrate radiochemicals in mining process and waste streams. The only thing

preventing these wastes from contaminating drinking water supplies downstream of

Curis’s mine is the effectiveness of Curis’s hydraulic control system and BADCT

elements. Even if these systems are completely effective and experience no failures,

Curis has nowhere addressed the issue of how it will deal with concentrations of

radiochemicals in pregnant leach solutions, raffinates, extracted hydraulic control

solutions, or evaporation pond effluent.

The use of sulfuric acid in uranium ISL mining has been prevalent in Europe.

The impacts of that mining on groundwater have been severe and long-lasting. For

example, in Straz pod Ralskem, in the Czech Republic, 3.7 million tonnes of sulfuric

acid was injected into the uranium ore body. Today, a contaminant plume has spread

beyond the mine area to cover approximately 13 square miles and is threatening the

drinking water supplies of two towns. In Bulgaria, 2.5 million tonnes of sulfuric acid

has been injected at various ISL sites. Approximately ten percent of the surface area of

these ISL mines is contaminated with solution spills, possibly preventing the proposed

return to use for agriculture. At Haskovo, sulfate concentrations are 1,400 mg/L, free

sulfuric acid is 392 mg/L, and pH is 2.2. At Navusen, sulfate concentrations are 13,362

mg/L, and with free sulfuric acid at 5 g/L, the groundwater actually constitutes mine

leaching solution.240

240 http://www.wise-uranium.org/uisl.html.

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A government commissioned study of two Australian in-situ uranium mines

discusses the impacts of acidic in-situ mining operations.241 These two particular mines,

Beverley and Honeymoon, use acidic in-situ solution instead of the alkaline solutions

often used by their U.S. counterparts. According to the study, the choice between acidic

and alkaline solutions depends upon a variety of factors including the host rock’s

composition. Both the Australian mines and Curis’s proposed mine use sulfuric acid

based in-situ solutions, just for different purposes – one for uranium extraction and the

other for copper extraction. Apparently, acidic in-situ solution is preferable for mining

because ‚*f+rom a process perspective, acid leaching has the advantage of achieving a

higher extraction of uranium in a shorter period <‛242 Thus, the solution Curis

proposes for copper mining is the preferred solution for uranium mining because it acts

quickly to mobilize radiochemicals in groundwater.

As confirmed by the Australian study, there are downsides to using acidic in-situ

solution. Groundwater restoration following acid leaching is generally considered to be

more difficult to achieve than after alkaline leaching.243 ‚Restoration to baseline levels

requires an extended treatment period.‛ According to the Australian study, such

restoration has only been demonstrated at one pilot site.244 Disposal of extracted

radiochemical laden materials is also an issue. The two Australian mines use re-

injection to dispose of unneeded extracted materials. When Australian officials

examined potential alternatives to re-injection, they discussed holding the uranium-

laden liquid in surface impoundments and the risks of public and worker radiation

exposures. Their discussion is enlightening, especially because Curis has not addressed

how they plan to deal with radiochemical materials. According to the study,

[n]ot re-injecting the waste into the aquifer would require either

sophisticated water treatment and/or the installation of much larger

evaporation ponds. Both would generate solid wastes to be disposed of in

a solid waste repository. When the wastes dried out they would become a

241 See generally CSIRO Land and Water, Review of Environmental Impacts of the Acid In-situ Leach

Uranium Mining Process (August 2004).

242 Id. at 9.

243 Id. at 11.

244 Id. at 9.

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possible dust source, which could increase the potential radiation

exposure of workers, in particular in relation to dust inhalation, but also

from radon inhalation and gamma exposure. Environmental radiation

levels at the surface would also increase.245

Because Curis plans to use surface impoundments, it is imperative that the risks of

potential worker and public exposure to dust inhalation, radon inhalation and gamma

exposure are considered. To date, this issue has been completely ignored by Curis.

The Australian study also recognizes that there are circumstances and places

where acidic in-situ leach mining is acceptable. The Beverley and Honeymoon mines

embody such examples because, they are located in remote areas and, in both instances,

the mining process was associated with a truly isolated, confined system in horizontally

bedded systems. Along with this, the upper aquifer contained groundwater of very

poor quality that did not serve as a drinking water source. But the study also

recognized that ‚*a+cid ISL mining can result in significant groundwater contamination

when used in an inappropriate location (OECD/NEA 1999) or when projects are not

well planned or correctly operated (IAEA 2001).‛246 As opposed to the Beverley and

Honeymoon mines located in remote areas, ‚well isolated from nearby aquifers‛247,

Curis’s proposed mine is adjacent to drinking water wells. The Oxide Bedrock Zone

proposed for mining also already communicates with the LBFU and UBFU. The

conditions and location of the proposed Mine are consistent with those described as

resulting in significant groundwater contamination.248

6.2.4 This Site Has Had a 10-Year History of Repeated High Level

Radiochemical Results.

Groundwater sampling conducted since 1995 reveals high concentrations of

radiochemicals in groundwater at the Curis site. This should not be unexpected, given

that an ISL technique used at uranium mines across the country is being employed at

245 Id. at 46.

246 Id. at 11.

247 Id. at 23.

248 Section 8 describes other contaminant issues at American uranium ISL mines.

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this site. But instead of recognizing and addressing the problem, Curis and its

predecessors have bent over backwards to deny any liability for the contamination.

When viewed as a whole, the groundwater data reveals that their denials lack merit.

6.2.4.1 Point of Compliance Well M14-GL

From the sampling data we have been able to review so far, it appears that site

operators began to receive high radiochemical readings as early as 1995. In July 1995,

total radium levels in the Lower Basin Fill Unit on the State Land parcel were measured

at seven times the AWQS in Point of Compliance Well M14-GL.249 Merrill Mining

characterized this sample as representing ambient conditions in the aquifer. That

characterization may be suspect, however, because M14-GL is located west of the

underground mine works excavated by Continental and is screened from 777 to 837 feet

bls—approximately the same depths as the mine shafts. Thus, it is possible that

groundwater in M14-GL, a point of compliance well proposed to be used during

Commercial PTF operations, could have been impacted by earlier mining activities

located to the east. It appears that there is insufficient evidence to support Curis’s

contention that groundwater flow is exclusively to the northwest and not at times to the

west, depending on off-site pumping.

Figure 15, Excerpt of Curis Figure 8-1 (Revised May 10, 2012)

6.2.4.2 Point of Compliance Well M21-UBF

In August 1996, total radium in the Upper Basin Fill Unit at BHP’s point of

compliance well M21 was found to be 16 times higher than the Arizona Aquifer Water

249 Merrill Mining, Site Investigation Plan for the Closure of the Florence Copper In-situ Mine

Project (Jan. 10, 2007) at 4-6.

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Quality Standard.250 M21 is a new monitoring well completed just a few months earlier

to a depth of 290 feet bls. It is located just north of the State Land parcel. Curis needs to

explain why this result is not indicative of groundwater contamination from

underground mining.

Figure 16, Approximate Location of POC Well M21-UBF251

6.2.4.3 BHP pilot test wells

In June 2001, four years after the pilot test was terminated, lab analysis of

groundwater samples revealed high radiochemical results:

250 Id. at 4-5.

251 Google Earth, 2012.

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Seven wells within the BHP pilot test area had adjusted gross alpha activity

concentrations higher than the AWQS of 15.0 pCi/L.

Six wells within the pilot test area had adjusted radium concentrations above

the AWQS of 5.0 pCi/L.252

As characterized by Radiation Safety Engineering, Inc., the laboratory that analyzed the

groundwater samples, water from the pilot test wells showed ‚significant

concentrations‛ of Ra226 and Ra228 and elevated levels of Ra224. The laboratory

concluded that

[b]ecause of the short half-life of Ra224 (3.6 days), this isotope is

rarely identified in the lab, but may appear in drinking water

delivered to homeowners if the transit time from the well to the

home is short< If any of these sources with observable Ra228

concentration are to be used for drinking water sources, we

recommend that they be tested for RA-224 before being put into

service.253

This warning, from a laboratory specializing in radiochemical analysis, indicates the

significance and seriousness of the radiochemical risks at this site.

252 Temporary Application, Attachment 10, Exhibit 10A (Groundwater Quality Data), Table 10A-

6 (Test Field Radiochemical Results) (March 1, 2012).

253 Radiation Safety Engineering, Inc., Letter to Brown and Caldwell (June 29, 2001).

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Figure 17, Test Field Layout From Proposed Cessation of Hydraulic Control Report

(B&C April 21, 2004).

In April 2004, nearly six years after the BHP pilot test, Merrill Mining asked

ADEQ and USEPA for permission to stop pumping the hydraulic control wells

surrounding the pilot project area. That request included a report that

noted radiochemical exceedances for December 2003 monitoring well samples – four

AWQS exceedances for adjusted alpha and seven exceedances for total radium.254 These


Test Field (April 21, 2004) at 3-3; see also Radiation Safety Engineering Inc., Radiochemical

Activity in Water Sampling Results (samples received Dec. 29, 2003 and analysis completed Jan.

13, 2004); Merrill Mining Site Investigation Plan for the Closure of the Florence Copper In-situ

Mine Project (Jan. 10, 2007), Appendix A, Summary of Analytical Data for Mine Block Test

Wells.

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exceedances were as follows:

BHP-2, a recovery well within the BHP pilot test area, had an adjusted gross

alpha activity concentration of 28.0 pCi/L in December 2003, following a June

2001 concentration of 57.0 pCi/L. Both of these concentrations are more than

twice the AWQS (15.0 pCi/L). This same well also had total radium

concentrations of 10.5 pCI/L in June 2001 and 8.5 pCi/L in December 2003,

both in excess of the AWQS (5.0 pCi/L).255 Since 2004, well BHP-2 has

continued to demonstrate high radium levels in excess of state standards,

with a concentration of 8.9 pCi/L in 2007 and 5.8 in 2010 pCi/L.256

In December 2003, CH1-B, a geochemistry cluster well screened at 500 feet bls

in the BHP pilot test area,257 had an adjusted gross alpha activity

concentration of 33.6 pCi/L, more than twice the AWQS, and total radium of

23.8 pCi/L, nearly five times the AWQS.258 The data also indicates that the

uranium concentration in CH1-B (68.4 pCi/L) were more than twice the

federal drinking water standard (30 pCi/L).259

CH1-R, part of the same geochemistry cluster well screened at 750 feet bls,

contained total radium at a concentration of 5.5 pCi/L in December 2003, in

excess of the AWQS.

CH2-R, another geochemistry cluster well screened at 750 feet bls in the BHP

pilot test area, had an adjusted gross alpha activity concentration of 20.0

pCi/L in December 2003 and total radium of 10.2 pCi/L. Furthermore, the

uranium concentration was three times the federal drinking water


Test Field, Table 6 (Test Field Radiochemical Results) (April 21, 2004).




Test Field, at 2-1 (April 21, 2004).

258Id. at, Table 6 (Test Field Radiochemical Results)

259Id. at, Table 6 (Test Field Radiochemical Results)

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standard.260

OWB-4, an observation well inside the BHP pilot test area, had an adjusted

gross alpha activity concentration of 22.7 pCi/L and total radium of 5.9 pCi/L

in December 2003. This followed concentrations of 34.0 pCi/L and 6.9 pCi/L

for gross alpha and total radium respectively.261 OMB-4 has continued to

demonstrate total radium levels higher than the AWQS, with concentrations

of 6.6 pCi/L in 2007 and 7.0 pCi/L in 2010.262

Despite the fact that all of these wells are located at the heart of the BHP pilot test

area, Merrill Mining dismissed these results as unrelated to acid leach mining. Merrill

claimed that the two cluster wells, CH-1 and CH-2, could not be completely purged,

such that the results ‚may not represent accurate concentrations in the test field.‛263 We

now know that at least one of these wells has continued to display radiochemical

concentrations in excess of applicable standards, indicating that the results cannot be

explained away so easily.264

Merrill also claimed that the results were indicative of background values,

because pH and sulfate levels indicated no impact from ISL mining. Amazingly, no

background sampling was conducted when these wells were installed, so there were no

baseline of natural conditions for comparison and their conclusions appear to be

supposition rather than documented fact.265 Furthermore, this conclusion is

contradicted by background data collected from 20 wells around the mine site in 1995,

before ISL operations of any kind began. This data, which includes up to seven rounds

260 Id.

261 Id.



263 Brown and Caldwell Proposed Cessation of Hydraulic Control at the Florence Project In-Situ

Test Field, at 3-3 (April 21, 2004).



265 Brown and Caldwell Proposed Cessation of Hydraulic Control at the Florence Project In-Situ

Test Field (April 21, 2004) at 3-4 and 5-10.

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of sampling per well during the summer and fall of 1995, indicates that background

levels of radiochemicals in groundwater across the 20 wells was well below applicable

federal and state levels.266

ADEQ’s analysis of the 2004 Brown and Caldwell report noted that radionuclides

were analyzed for all wells in June 2001 and December 2003 and revealed ‚numerous

exceedances of gross alpha particle activity and total radium above AWQS at various

wells.‛267 USEPA questioned the radiochemical results in a 2005 email discussing the

fact that radiochemical levels in three wells were above the federal maximum

contaminant level for uranium and that levels had ‚actually increased significantly

from 2001 to 2003.‛ USEPA indicated that their review revealed nothing ‚that would

explain that this increase is natural.‛ USEPA also questioned why numerous wells

were not sampled for uranium in 2003 and whether it would be useful to sample the

pilot project observation wells and recovery wells for uranium. 268

Apparently, Merrill Mining was required to take additional samples because a

June 2005 letter report from Brown and Caldwell included radiochemical analysis for

samples taken in May from CH1-R, CH1-B, CH2-R, and CH2-B. Adjusted gross alpha

and total radium concentrations were below applicable standards for all four wells.

Brown and Caldwell concluded that the data confirmed their earlier assessment that

‚the previously recorded high values were not representative of the water quality at the

well’s location but were the result of inadequate purging of the permanently mounted

down-hole sampling devices.‛ Again, this conclusion—based on a single sample at

each well—appears to be undermined by subsequent data for CH1-R that shows total

radium and uranium levels in excess of federal and state standards after the 2005

samples were taken. It is unclear why Merrill Mining was not required to resample

wells BHP-2 or OWB-4, both of which have continued to demonstrate radiochemical

exceedances through 2010. Nevertheless, USEPA approved closure of the pilot project

wells in July 2005.

266 Magma Copper Company, Site Characterization Report, Table 4.5-4 (Summary of Analytical

Results-Radiochemicals) (January 1996).

267 ADEQ, Letter to Vanguard (August 16, 2004), attached ADEQ Inter-Office Memorandum.

268 Douglas Liden, Email message regarding Merrill Mining to Barry Rechtorovich, ADEQ (April

6, 2005).

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6.2.4.4 Point of Compliance Well O19-GL

In October 2005, Merrill Mining reported an exceedance of the permit alert level

for gross alpha activity in groundwater at Point of Compliance well O19-GL. POC well

O19-GL is screened in the oxide zone in the northwest corner of the Curis property,

approximately 150 feet north of the State Land parcel.269 Curis needs to explain why

this result is not indicative of groundwater contamination from underground mining.

6.2.5 Curis Completely Ignores Radiochemical Concentrations in Process

Streams, Waste Streams, and the Impoundment Pond.

Nowhere in its application materials has Curis discussed how it will handle

process and waste streams containing elevated levels of radiochemicals. Mobilized

uranium, radium and other radiochemicals will be present groundwater extracted from

Curis’s recovery wells. Curis has not indicated whether it will attempt to extract

radiochemicals from leach solutions, using an ion exchange column or other means. If

radiochemicals are to be extracted, Curis should address how the extracted radioactive

materials will be handled, stored, and disposed. If not, Curis should explain the

impacts of recirculating and concentrating radiochemicals in the leach solutions. Curis

also should explain the risks and impacts of radiochemicals in the impoundment pond

wastewater and sediments, as well as how Curis will handle potentially radioactive

pond sediments upon termination of mining activities. As the Australian study of

uranium ISL mining reported, drying pond sediments and other dry mining waste can

become an airborne hazard to workers and residents ‚in relation to dust inhalation, but

also from radon inhalation and gamma exposure.‛270

6.2.6 Conclusion

269 Merrill Mining, Letter to Mr. Doug Liden, USEPA (October 28, 2005) at 1; see also Merrill

Mining Site Investigation Plan for the Closure of the Florence Copper In-situ Mine Project (Jan.

10, 2007), Appendix B, Summary of Analytical Data for all POC Wells, at 344.

270 CSIRO Land and Water, Review of Environmental Impacts of the Acid In-situ Leach Uranium

Mining Process, at 46 (August 2004).

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Curis and its predecessors have ignored or downplayed the risks associated with

radiochemicals at this site. As a result, little investigation of the impact of ISL mining

on radiochemicals at the site has been conducted. Curis also has proposed only limited

monitoring of radiochemical data and has no contingency or emergency response plans

to address radiochemical contamination. The refusal to investigate, much less address,

the risks associated with radiochemicals at this leave nearby drinking water sources

unprotected from the risk of radiochemical contamination. For this reason alone,

ADEQ should deny Curis’s request.

Uranium, radium, radon and other radiochemicals are frequently found in

association with copper ore deposits throughout Arizona. Copper mining, particularly

the leaching of copper with acid solutions, is known to mobilize and concentrate

radiochemicals in groundwater, process solutions, and mining waste streams. Based on

data collected from the Curis site, USEPA has concluded that radiochemicals at the site

are leachable and that process and waste streams will concentrate radiochemicals.

USEPA’s conclusion is borne out by historical evidence and data from the Curis

site. At least one mining company has been interested in the Curis site for uranium

mining. Groundwater sampling over a ten-year period indicates that radiochemicals

exist at this site at background levels that may exceed drinking water standards.

Undisturbed, these radioactive materials pose no risk to residents of the area.

Unfortunately, these radioactive materials will not remain undisturbed if Curis is

permitted to mine this site. Many of the results described above arose after a brief pilot

test of the in situ acid leach process in the mid-1990s. An undeniable risk exists that

Curis’s injection of over five billion pounds of sulfuric acid over a 20-year period will

result in much more serious impacts to drinking water sources and the environment.

To date, mining companies at this site have chosen to ignore those risks.

It is imperative that ADEQ investigate and address this matter thoroughly before

a permit decision is made. Additional testing, sampling, and analysis is required, at a

minimum, to ensure that the issues described in USEPA’s TENORM report are

thoroughly understood and can be addressed using available technology. Furthermore,

Curis should be required to explain how it will control migration of these materials and

how it will handle, control, store and dispose of radiochemical-contaminated

groundwater, mining solutions, waste streams, and impoundment pond sediment

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during mining activities. Curis should also be required to conduct more vigorous

sampling for these contaminants than the meager sampling regimen it currently

proposes and should be required to explain contingency measures for the escape of

these contaminants beyond its hydraulic control well field. Finally, the cost of these

efforts should be added to Curis’s cost estimates for purposes of financial assurance, as

none of these issues would be covered by the costs Curis has included in the current

estimates. If Curis does not adequately address these concerns ADEQ should deny

Curis’s application in its entirety.

6.3 Increasing Sulfate Trends in the Proximity of the Previous Well

Field Raise Concerns About the Impacts of the BHP Pilot.

Analysis of the publicly available data generated from the BHP Pilot test

demonstrates a trend of rising sulfate levels within the vicinity of the previous pilot.

This trend is especially present on the western edge of the BHP Pilot well field. As the

hydrographs in Figure 18 demonstrate, the persistent rise in sulfate levels begins in 2004

and continues through the year 2010. Just because the sulfate increase didn’t appear

until years after the BHP Pilot is not reason to dismiss the connection. This lag in time

between the previous pilot’s injection and extraction activity and the sulfate level

increases is consistent with the experience of other in-situ mines. At uranium in-situ

mines across the country chemical concentrations in groundwater beneath the well

fields have increased over time after restoration was complete.271 And as will be

discussed below in these comments, sulfate is a constituent of concern, especially given

the vulnerable populations directly downstream from Curis’s proposed mine.

In response to ADEQ’s request to address, within its Contingency Plan, potential

sulfate levels exceeding 750 mg/L after the suspension of hydraulic control for 30

days,272 Curis simply provided that they planned to establish a new indicator sulfate

271

See United Stated Geological Survey, Groundwater Restoration at Uranium In-Situ Recovery

mines, South Texas Coastal Plain, Open-File Report 2009-1143 (May 11, 2009); See also USGS,

Consideration of Geochemical Issues in Groundwater Restoration at Uranium In-Situ Leach mining

facilities, NUREG/CR-6870 (January 2007) 272 ADEQ May Deficiency Letter at Item 6.

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concentration.273 Merely changing the indicator level does nothing to protect the

drinking water aquifer. Instead what it does is shift the responsibility for treating

sulfate to the drinking water providers. ADEQ should require Curis to maintain sulfate

levels that are protective of the drinking water aquifer by imposing such permit

conditions ahead of any problems and then impose proper investigation, reporting and

treatment conditions if that level is compromised. Don’t allow Curis to just push the

problem down to someone else.


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Figure 18, Sulfate Hydrographs for BHP Pilot Test Well Field

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7 Curis’s Commercial PTF Is Premised on Fundamentally

Flawed Computer Modeling That Fails to Recognize Real

World Conditions.

Curis has submitted two different versions of its groundwater model to ADEQ

and USEPA. The Florence Copper Project Model (FCP Model) was submitted with the

January 2011 APP application. The FCP model covers a 10.4 by 12 mile area

surrounding the Commercial PTF site. It has 10 model layers to represent the

hydrostratigraphic layers in the area:

o Layers 1 and 2: Upper Basin Fill Unit (UBFU)

o Layer 3: Middle Fine Grained Unit (MFGU)

o Layers 4 and 5: Lower Basin Fill Unit (LBFU)

o Layer 6: 40-foot Exclusion Zone of the Bedrock Oxide Unit

o Layers 7 through 10: Bedrock Oxide Unit

The FCP Model was calibrated to groundwater level measurements on a sub-regional

scale, and is not appropriate for making site-level flow and transport predictions. Head

residuals—the margin of error between real-world measured groundwater levels and

model-simulated levels—in the proposed mining area were as high as 75 feet.

The Underground Injection Control Model (UIC Model) was submitted in March

2011 to the USEPA with the UIC application. This model covers a 2.5 by 2.4 mile area

surrounding a ‚typical‛ In-Situ mining block. This model incorporates three model

layers to represent the hydrostratigraphic layers in the area:

o Layer 1: Lower Basin Fill Unit (LBFU)

o Layer 2: 40-foot Exclusion Zone of the Bedrock Oxide Unit

o Layer 3: Bedrock Oxide Unit

The UIC Model uses homogeneous hydraulic properties within each layer based on

values used in the FCP Model; however, it is not calibrated to match any observations

made at the mining block scale.

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Curis’s groundwater models give rise to numerous concerns.

7.1 Conceptual models for simulating contaminant flow and transport

at the site level have not been adequately developed.

Curis has identified the relative importance of major faults in the area for

controlling flow at the sub-regional level. However, the character of flow at the scale of

a resource block has been poorly defined, and the importance of heterogeneity and

anisotropy of fractures throughout the oxide bedrock zone at this scale has not been

properly addressed. The potential for secondary porosity to slow the recovery of

impacted ground water has not been characterized. Analysis of information gained

from the 1997 BHP pilot test, and additional testing and analysis (e.g. fluorescent dye

tracer test at a resource block) is needed to refine the conceptual model(s) used to model

contaminant flow and transport for the proposed in-site leaching activities. This

analysis is critical, as flow at this scale is proposed to control the release of

contaminants.

ADEQ has requested more detailed data and analysis regarding various model

inflows and outflows related to surface water infiltration, canal leakage, agricultural

returns, evapotranspiration, and other inputs for use in constructing a water balance for

the Commercial PTF well field area.274 Curis’s response identified components of the

sub-regional water balance, and stated that the contribution of these components at the

Commercial PTF well field scale would ‚attribute an apparent false level of precision to

the model results.‛ This lack of precision in the water balance at the Commercial PTF

well field area needs to be quantified and understood as it has the potential to

significantly impact the ability to maintain hydraulic control.

Curis’s FCP Model also assumes that once the target sulfate concentration of 750

mg/L is reached in the recovered water during the rinsing period, that there is no

potential for residual water exceeding this value. 275 This assumption in a fractured rock

aquifer is not realistic without testing to demonstrate the ability to fully recover the

contaminants (e.g. the fluorescent dye tracer test). While fluids are expected to transmit

274 May Deficiency Letter Item 23.

275 See Temporary Application at § 14A.6.2.1.

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through interconnected fractures in the rock, it is also possible that there are other voids

and pore spaces in the rock that do not freely transmit fluids. Diffusion of constituents

from the leach solution into water within any less connected voids may occur. During

the rinsing phase, removal of those constituents will require diffusion to occur in the

opposite direction, and this can significantly affect the number of pore volumes

required to adequately reduce concentrations in the oxide bedrock aquifer. Since

flushing the interconnected fractures can occur much faster than the diffusion process,

concentrations shown to be reduced by the rinsing may subsequently rise after rinsing

is complete as the contaminants in the non-connected voids come to equilibrium with

the residual fluid in the connected fractures. In fact, rises in sulfate and other

constituents observed in the BHP test block wells subsequent to injection testing,

rinsing, and pumping may be attributable to diffusion. This phenomenon is often

modeled using a dual-porosity method which was not employed by Curis in either the

FCP or UIC models.

7.2 The models have not been sufficiently calibrated for making

contaminant flow and transport predictions at the site level.

The BHP 1997 pilot test data to characterize the flow of groundwater and the

transport of injected fluids from injection wells into the oxide zone. As ADEQ has

noted, Curis has not indicated what, if any, specific parameters from BHP’s pilot test

were used in making Curis’s groundwater assumptions. Review of the Curis submittals

indicates that the information obtained during and after the BHP pilot test have not

been adequately addressed and incorporated into the groundwater flow and

contaminant transport models.

Curis has claimed from the beginning that the BHP pilot test proved that

hydraulic control of mining solutions and contaminants can be maintained at this site

using the well configurations proposed by Curis. Curis cites to a single short letter from

BHP to ADEQ as evidence of the success of BHP’s test. Curis also cites its own selective

and self-serving analysis of subsequent groundwater data from the site as evidence of

hydraulic control and the absence of groundwater impacts from BHP’s test.

But as far as we know, Curis has never attempted to incorporate data from the

BHP test into its groundwater models and calculations. Curis’s groundwater modeling

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efforts are a key component of its application, influencing or defining the Area of

Review; Zone of Endangerment; construction, location, and configuration of ISL and

monitoring wells; monitoring requirements; injection pressures; mining solution

characteristics; cost estimates; closure requirements; and countless other factors. As a

result, the accuracy of the model should be a primary concern in the permitting process.

The absence of any attempt to calibrate the model against site-specific data from 1997

and afterward raises serious questions about the model’s quality and accuracy.

These concerns are supported by other evidence indicating that BHP’s pilot test

was not as successful as Curis would have everyone believe. In letters from Merrill

Mining, who bought the mine site from BHP, the company expressed serious concerns

that the projections upon which the original UIC permit was based were not supported

by BHP’s 1997 pilot test:

Merrill noted that ‚there were major disparities between the results of field

tests and the assumptions regarding the copper recovery mechanisms and

recovery rates that were used to justify the permits for, and the economic

viability of the Florence Copper Project. The disparities led BHP Copper to

conclude that the field test results did not justify building a leach facility at

Florence . . . .‛276

In a Draft Field Test Report prepared by BHP in October 1999, but apparently

never publicly disclosed, BHP noted substantial disparities between the

recovery rates measured during the 1997-98 field test and the data used to

justify the project during permitting, concluding that ‚If the solution

chemistry in the production well BHP-1 is, in fact, a result of water-rock

reactions, in-situ leaching at Florence may not be possible.‛277

BHP also concluded in the Draft Field Test Report that much longer leach

times might be required to obtain copper at commercially-viable levels, with

modeling suggesting leach times of 6 to 8 years. This could, in turn, double

the mine life of the project, with the total time between the start of production

and closure possibly exceeding 45 years.278

276 Letter from Roger Ames, Registered Geologist, Merrill Mining, to Bryan Wilson, President

and CEO, Mohave Resources, Inc., at 1 (November 21, 2006) (Attachment 1). 277 Id. at 2 (citing Draft Field Test Report, at 109). 278 Id. at 2-3.

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BHP recommended that a new field test be conducted for a much longer

duration and employing a multiple-cell test field and expanded water

management system. As a precursor to a second field test, BHP

recommended an ‚improved understanding of the geochemical and

hydrogeological mechanisms at work before attempting the design of a new

field test.‛279

Curis has never mentioned, must less addressed, any of these concerns. Nor has

Curis acted on BHP’s recommendation that a better understanding of geochemical and

hydrogeological mechanisms be developed before designing a new field test. Instead,

Curis has relied almost exclusively on BHP’s investigations leading up to the 1997-98

field test and has performed little new investigation of its own.

The lack of additional investigation, the absence of any attempt to

calibrate its new groundwater model simulations with the BHP data, and the proposal

to conduct ISL mining under essentially the same standards as in the BHP permit is

deeply concerning in light of the questions that BHP’s pilot test provoked. But later

investigation by BHP’s successor at this site raised additional questions. Merrill Mining

expressed concerns that its own groundwater sampling and testing ‚indicated that a

significant decrease in pH could occur if leaching of the deposit proceeds as currently

authorized by the permits. The methods discussed in the Report for increasing copper

recovery would further exacerbate the low pH problem and could mobilize heavy

metals and radiological elements. Merrill does not know how the low pH issue can be

successfully addressed.‛280

The BHP pilot test data should be used to calibrate the groundwater flow models

on a site-scale to make model predictions of local flow and transport consistent with

what has been observed to date. Sensitivity to key model inputs at the local level

should also be tested. For example, the horizontal and vertical anisotropy of the oxide

bedrock unit should be tested as these parameters have not been sufficiently

characterized. Additionally, fluorescent dye tracer tests should be conducted after

installation, but before mining at each resource block to characterize local flow

characteristics. Model calibration to those tracer tests should be done to optimize well

279 Id. at 3 (citing Draft Field Test Report, at 102 and 110-111). 280 Id. at 4.

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pumping rates to maximize recovery of PLS and to ensure hydraulic control can be

maintained.

It is clear that Curis’s current models do not match real-world data. For instance,

ADEQ has pointed out that:

The Application indicates that based on previous pilot testing <and

recent groundwater modeling <it will take approximately 12 months for

Phase 1 and 24 months for Phase 2 to meet the indicator sulfate

concentration in the mine block wells. <It appears the previous applicant

rinsed the mine block for approximately twenty two months <and

pumped the mine block for approximately six years<, and eight of the

mine block wells had a pH value of less than 6.5 <and numerous wells

had constituents that did not meet the secondary Maximum Contaminants

Levels (MCLs) for TDS, sulfate, aluminum, copper and manganese.‛281

In other words, Curis’s groundwater modeling assumptions do not match the real-

world data collected from the BHP pilot test.

Concentrations of dissolved sulfate and other ions have been measured quarterly

since 2000. The results for sulfate and other analytes from the BHP pilot test wells

clearly show increasing concentrations of some contaminants between December 2003

and June 2010. For instance, as depicted in Figure XX, below, sulfate levels have been

steadily increasing over this period. Consistent with groundwater flows to the west

and northwest, the wells in the western portion of the pilot test well field have higher

levels of sulfate than those to the east. This indicates that acid mining solutions injected

during BHP’s pilot test are still impacting the aquifer, directly contradicting Curis’s

claims that there are no lingering impacts from the BHP pilot test. Curis should

calibrate its models against these data to refine its predictions regarding mining impacts

and hydraulic control.

Review of data from other sites could also help with refining the two

groundwater models. ADEQ requested a comparison of the geochemical model data to

281 September Deficiency Letter, p. 20, HD ¶70.

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data from similar facilities to determine if Curis’s predicted concentrations were

reasonable in light of real-world data.282 Curis responded that no other in-situ copper

recovery operations are suitable analogs to Florence Copper Project, a point we have

been making for some time. The fact that no comparable mining projects exist is all the

more reason to require additional investigation of the Commercial PTF site before a

permit decision is made.

7.3 The UIC Model may be too simple to simulate site conditions,

making it unsuitable to demonstrate that hydraulic control will be

maintained and contaminants will not migrate away from the site.

The UIC Model is a much-simplified model, with three horizontal layers and

homogenous aquifer characteristics assigned to each layer. The layers do not conform

to varying elevations of the contacts between units that would be seen in any 2.5 by 2.4

mile area in the proposed mining area. Furthermore, boundary conditions and other

aspects of the model may have significant influence on the groundwater flow at the site,

but their development was not reported.

There also are mass balance errors in the UIC Model that may be causing

significant errors in the predicted groundwater flow patterns. Review of some of the

MODFLOW list files provided reveals that the percent discrepancy between total model

domain-wide water inflows and outflows exceeds 5% in approximately 80% of the

times steps listed, and exceeds 20% in 20 to 30% of the time steps listed. Generally,

mass balance errors less than 1% are acceptable in common modeling practice.

7.4 Geochemical Evaluation of Forecast Process Solutions

Curis prepared a document purporting to analyze the chemistry of various

process solutions and waste streams using a geochemical model based upon various

assumptions and calculations. The document purports to ‚support the design of the

ISCR system that maximizes the recovery of the copper from the ore reserve while

minimizing the migration of heavy metals and other constituents into surrounding

282 May Deficiency Letter at Item 3.

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groundwater.‛283 It is not clear how results of this report were utilized to support

design of the ISCR system since the proposed Curis PTF well field is essentially

identical to the well field utilized by BHP.

The forecast composition of commercial grade PLS ‚was derived by SWS by

inspection of the PLS recovery curves in BHP injection wells BHP6, -7, 8, and 9 after

inversion of those wells from injection to recovery in 1998. This occurred after the

initial raffinate injection phase between November of 1997 and February of 1998. The

PLS that was then recovered in these wells between May and July of 1998 is taken as the

most ‚mature‛ leach solution as it had the longest residence time in the ore body during

copper recovery.‛ This passage appears to indicate that PLS samples were recovered as

much as 5 months after injection activities had been discontinued. Curis states in the

APP application for the PTF284 that groundwater was injected prior to converting to

recovery, suggesting that the recovered fluid would not be representative of mature

PLS. The geochemical model documentation refers to a sample from BHP-9 collected

on June 16, 1998, but these data are not provided in any other documents.

Unfortunately, no documentation regarding the results of the actual pilot test has ever

been made available. Curis should be required to provide or clarify the following:

1. Curis should provide all geochemical data available for the BHP pilot test.

2. Curis should provide a discussion of the processes that were being conducted

during the 5-month period after injection activities had been discontinued.

3. Curis should explain how samples from this solution are considered to be

representative.

283

Temporary Application, Exhibit 10C. 284

Temporary Application, Attachment 10.

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8 Curis’s Proposals for Cleaning Up its Groundwater Pollution

Are Overly Optimistic.

ISL mining purposefully injects contaminants, such as sulfuric acid, into

groundwater to recover target minerals, such as copper. The process mobilizes many

other pollutants, such as heavy metals, sulfate, and radiochemicals into groundwater.

Once mining is complete, those contaminants and pollutants are supposed to be cleaned

up by the mine operator. The most common method of doing this is to inject clean

groundwater into the mine area while simultaneously pumping groundwater from the

same area. This ‚sweep‛ or ‚rinsing‛ process is supposed to eliminate contaminants

and restore the aquifer to pre-mining conditions.

Curis has proposed to rinse the aquifer beneath the Commercial PTF well field

for nine months after Commercial PTF operations end. It proposes to then let the

aquifer ‚rest‛ for thirty days and sample groundwater quality. If groundwater meets

the standards that Curis has proposed, cleanup will be considered complete.

Curis’s proposal ignores a wealth of data from other ISL mines around the

country that indicate groundwater rinsing takes much longer than Curis projects. For

instance, at ISL operations at other mines around the country, restoration has had to

continue for much longer than 24 months, with many mines having to request amended

groundwater quality goals because they could not reach the original goals of their

permits. Examples of restoration periods at American ISL mines include the following:

El Mesquite Mine, TX: 10 years.

Holiday Mine, TX: 8.5 years.

Mt. Lucas, TX: 7 years.

O-Hern Mine, TX: 7 years.

West Cole Mine, TX: 8 years.

Zamzow Mine, TX: 8 years.285

Smith Ranch-Highland Mine, WY: Projected 2.8 to 12 years.286

285 Southwest Groundwater Consulting, Report on Findings Related to the Restoration of

Groundwater at In-Situ Uranium Mines in South Texas (September 29, 2008).

286 Cameco Letter to U.S.N.R.C. (August 13, 2009).

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Crow Butte Mine, NE: Requesting 9 years instead of 24 months required by

permit.287

Curis also ignores data indicating that rebound of contaminants can occur in

groundwater up to six months or more after groundwater rinsing stops. Curis also

ignores the history of the BHP pilot test, where groundwater rinsing and monitoring

continued for years without a demonstration that the aquifer had been restored to

applicable standards.288

Curis may argue that if its predictions for groundwater restoration are overly

optimistic, it just means it will have to continue restoration for a longer period and will

not be excused from meeting the permit requirements for restoration and closure of the

Commercial PTF. Hopefully, that is true. But Curis’s predictions in this regard have

other ramifications. Curis has indicated it will continue to seek Phase 2 commercial

mining permits even before the Commercial PTF is complete. Without the data from

Curis’s attempts to restore groundwater after Commercial PTF operations, a Phase 2

APP permit likely will have inadequate or incorrect standards and requirements. This

could lead to the need for revisions to the Phase 2 permit, revisions that could be

negotiated without public input. Curis’s predictions also significantly impact its cost

estimates for closure and reclamation. Optimistic predictions likely understate the cost

of restoring groundwater at the site, leading to inadequate financial assurance. That, in

turn, leads to a greater risk that Arizona taxpayers will be forced to pay for cleanup of

this site. For these reasons, Curis’s restoration plans require greater scrutiny and

significant changes to make for a conservative and protective approach to this

important issue.

287 Cameco Letter to U.S.N.R.C. (December 21, 2010).

288 See Section 6.

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8.1 A Federal Report on Uranium ISL Mines in Texas Concluded That

Mine Operators Could Not Restore Groundwater to Pre-Mining

Levels.

In 2009, the United States Geological Survey (USGS) examined groundwater data

from 27 ISL uranium mines in Texas, comprised of 77 individual well fields.289 The

purpose of the study was to determine whether groundwater had ever been returned to

baseline, pre-mining conditions at any of the 77 well fields. Texas uranium mines use

alkaline solutions, which are generally easier to clean up than the acid solutions

proposed for use at by Curis.

In Texas, 26 chemical constituents are measured before mining to establish

baseline conditions in groundwater. Average baseline conditions in the production

areas become the goal for remediation and restoration of groundwater after mining

ends. The 26 chemicals for which goals are established include:

10 chemicals for which USEPA has established Maximum Contaminant

Levels (MCL) under the Clean Water Act.

5 chemicals for which USEPA has established secondary or recommended

standards that are not legally enforceable but that may negatively affect the

aesthetic quality of groundwater or have health impacts in sensitive

populations.

11 chemicals for which there are no established MCL or secondary standards.

Final sample results were available for only 22 of 77 well fields at 13 of the 27

mines studied. Based on those results for the 26 chemicals analyzed, which are

summarized in Figure XX, the USGS concluded that mine operators failed to return post-

mining groundwater to baseline conditions at any of the 22 well fields. More than half of the

well fields could not restore groundwater to baseline conditions for selenium and

uranium. Sulfate concentrations could not be restored to pre-mining levels in 86% of

the well sites. Three-quarters of the well fields could not return groundwater to pre-

mining conditions with respect to calcium, magnesium, ammonia, alkalinity, and

289 United States Geological Survey, Groundwater Restoration at Uranium In-Situ Recovery Mines,

South Texas Coastal Plain, Open-File Report 2009-1143 (May 11, 2009).

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conductivity. Fluoride, salts and other dissolved solids, sodium, and molybdenum

remained above pre-mining levels at a third of the well fields.

Figure 19, Groundwater Chemistry Data, USGS Report

Due to the inability of mine operators to meet baseline standards, the USGS

noted that state regulators had to amend the groundwater restoration goals for at least

one chemical for every uranium in situ well field in Texas. The original restoration

goals required in the mines’ operating permits, goals the mine operators probably

assured the public they could meet, had to be relaxed because restoration to those

standards proved impossible or infeasible.

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Moreover, once restoration activities stopped, groundwater conditions could

actually worsen rather than remain stable. Generally for the period at issue, operators

of the Texas well fields were required to monitor for only six months after mining

ceased and ‚restoration‛ of the well fields was completed. Looking outside of Texas,

the USGS noted that chemical concentrations in groundwater beneath uranium in situ

well fields in Wyoming, Colorado and New Mexico began to increase over time after

restoration was complete. For instance, at a Grover, Colorado pilot test site uranium

and other radioactive constituents, calcium, magnesium, ammonia, total dissolved

solids, and other chemicals began increasing—sometimes dramatically—more than six

months after mining activities ceased. Regulators and industry experts appear uncertain

why this occurs, but it indicates that the effects of ISL mining can not only linger, but

actually worsen after restoration activities have stopped.

Figure 20: Post-Reclamation Uranium Levels in Groundwater

at Grover, Colorado In Situ Uranium Mine

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Mine operators routinely address their inability to restore groundwater by

simply asking for revised standards in their operating permits. For instance, restoration

goals for uranium were increased by 1,060% at the Hobson mine, 4,155% at Longoria,

290% at O’Hern, 900% at Pawlik, and 29,900% at the Zamzow mine. Arsenic goals at

two of these mines were increased by 181% and 1,438%. Sulfate goals were amended at

each of these mines through an increase of 62% to 1,685%.290 Although the uranium

industry touts its success with restoring groundwater after ISL mining, ‚successful

restoration‛ is obviously a relative term.

8.2 Pollutant Rebound Can Take Months or Years to Detect and

Address.

Curis proposes to monitor one time for pollutant rebound in the aquifer after

Commercial PTF operations and groundwater rinsing are complete. This single

sampling event is proposed to occur thirty days after groundwater rinsing stops.

Pollutant rebound after ISL mining has been shown to occur months or years after

groundwater rinsing efforts have stopped. Curis’s proposal is completely inadequate.

Curis should be required to monitor for rebound on a quarterly basis for at least a year

after groundwater rinsing stops and then periodically for at least ten years thereafter.

Other mines have demonstrated that ISL mine operators have experienced an

inability to stabilize the aquifer on a permanent basis. The USGS conducted a study of

groundwater restoration and uranium ISL mines in 2007 as background for improved

groundwater models in this regard. The USGS found that elevated concentrations of

arsenic, selenium, radium, uranium, molybdenum and vanadium remained in aquifers

after ‚extensive groundwater restoration activities.‛ As a result, ‚a long period (5

years) for the groundwater stabilization phase may sometimes be needed‛ and ‚long-

term monitoring (13 years) may be required‛ to ensure that contaminants have

stabilized in the aquifer. The USGS concluded that rebound may be due to ‚mixing and

290 Southwest Groundwater Consulting, LLC, Report on Findings Related to the Restoration of

Groundwater at In-Situ Uranium Mines in South Texas (September 29, 2008).

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diffusion of water from lower permeability zones into regions with higher

permeability,‛ or due to increasing oxidation within the aquifer.291

8.3 ISL Uranium Mines Have Experienced Significant Difficulty With

Groundwater Restoration

Information from other ISL mines does not support Curis’s optimistic predictions

relating to groundwater restoration. The difficulties encountered in restoring

groundwater at three uranium ISL mines are summarized below.

8.3.1 Crow Butte In-Situ Leach Uranium Mine, Dawes County, Nebraska

Crow Butte Mine is located 5 miles southeast of the City of Crawford. Dawes

County’s predominant land use is livestock grazing and feed production. Dawes

County had a land mass of 1,297 square miles and a population of just over 9,000 in

1998 (6.5 people per square mile). The project site is approximately 2,560 acres.

In September 1984, the Nuclear Regulatory Commission (NRC) issued an

Environmental Assessment (EA) for research and development (R&D) scale operation

of a uranium mine at the site. The mine operator projected that it would have to pump

and treat 6.27 pore volumes (26.3 million gallons) to completely rinse and restore the

aquifer after mining was complete.292 The NRC stated that the aquifer underlying the

project site had been designated for drinking water use by the State of Nebraska and

that, if groundwater could not be restored to baseline quality after mining for every

contaminant or parameter, at a minimum the drinking water use category would have

to be met.293

R&D operations began in July 1986. After R&D operations, the NRC approved

restoration of the R&D well field in April 1988, but was able to do so only through a

finding that groundwater was returned to conditions consistent with pre-mining uses,

291 USGS, Consideration of Geochemical Issues in Groundwater Restoration at Uranium In-Situ Leach

Mining Facilities, NUREG/CR-6870, at 23 (January 2007).

292 1984 EA at 55.

293 1984 EA at 55.

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rather than the original permit standard of a return to groundwater quality consistent

with baseline conditions.294 The mine operator had to pump and treat 19 pore volumes

of groundwater to obtain restoration, over 3 times the original estimate.

In October 1987, the mine operator applied for a license to allow commercial

scale operations. Similar to what Curis has proposed, the operator stated that ‚*t+he

long term impacts on the groundwater quality should be minimal since restoration of

the wellfield will be accomplished during operations.‛295 In December 1989, the NRC

issued an EA and a license for commercial operations. The license stated the ‚primary

goal of restoration shall be to return the groundwater quality, on a mine unit average, to

baseline conditions.296 However, because R&D operations had shown that baseline

conditions could not always be met, a secondary goal of ‚quality consistent with

premining use‛ also was discussed in the EA.297 The EA projected that it would require

only 24 months for remediation of groundwater within individual mining blocks, and

36 months to decommission the site after all mining was completed.298 This is consistent

with NRC regulations, which require groundwater restoration within 24 months, unless

otherwise extended by the agency.

Since Crow Butte’s license was issued in December 1989, mining operations and

groundwater restoration have been completed only at Mine Unit 1. Commercial

operation of Mine Unit 1 began in April 1991.299 Operations ended and Mine Unit 1 was

placed into restoration phase in March 1994. Four years later, groundwater restoration

still was not complete, but the mine operator projected that treatment would be

completed by April 1998.300 That deadline was not met.

294 Dec. 1989 EA, at 43.

295 Application at 7.2(1).

296 License, ¶ 10.3(C).

297 EA at 41.

298 EA Table 3.3.01.

299 Mine Unit 1 Restoration Report, at 12.

300 1998 EA at 44.

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Between May 1994 and August 1999, more than 626 million gallons of

groundwater from Mine Unit 1 were processed and treated at a cost of over $365,000.301

Despite this effort, however, nine contaminant parameters still exceeded baseline, pre-

mining conditions (arsenic, radium-226, vanadium, calcium, potassium, magnesium,

uranium, alkalinity, and bicarbonate).302 The mine operator requested approval of

groundwater restoration at Mine Unit 1 based on a secondary goal of restoration of

groundwater to conditions suitable for pre-mining uses—livestock grazing and other

agricultural uses.

In November 1999, the Nebraska Department of Environmental Quality accepted

groundwater restoration of Mine Unit 1.303 In January 2000, the mine operator

requested that the NRC approve completion of Mine Unit 1 restoration.304 At the

request of the NRC, the mine operator submitted additional information in support of

restoration closure for Mine Unit 1 in August 2001. In March 2002, the NRC denied

approval of Mine Unit 1 restoration and ordered the mine operator to immediately

restart stabilization groundwater monitoring because sample data ‚do not demonstrate

that the restoration activities in Unit 1, have resulted in constituent levels that will

remain below levels protective of human health and the environment.‛ The

accompanying staff report stated that ‚Staff’s analysis indicates that concentrations of

ammonium, iron, radium-226, selenium, total dissolved solids, and uranium show

strongly increasing concentration trends over the stability monitoring period.‛305 The

mine operator was eventually able to demonstrate groundwater stabilization and

groundwater restoration was approved in March 2003—nine years after restoration

began.306

Subsequent experience has confirmed the mine operator’s inability to restore

groundwater at Crow Butte. In January 1996, Mine Unit 2 was placed into restoration.

The mine operator failed to restore groundwater to baseline conditions within two

301 August 2001 Response to Request for Additional Information, at 3 and 13.

302 Mine Unit 1 Restoration Report, at 35.

303 August 2001 Response to Request for Additional Information, at 2.

304 Mine Unit 1 Restoration Report.

305 2002 Denial, Wellfield Unit 1 Groundwater Restoration Denial.

306 Approval Letter, Mine Unit 1 Restoration.

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years, as originally promised, but in 1998 the mine operator estimated the groundwater

restoration would continue for only another two years. That deadline was missed as

well. In February 2004, with restoration still incomplete, the mine operator submitted

revisions to the Groundwater Restoration Plan for Mine Unit 2.307 Five years later, with

restoration having continued for eleven of the previous thirteen years, the mine

operator requested an alternative decommissioning schedule under which restoration is

projected to have been completed by July 1, 2012—over 16 years after restoration began.

Groundwater restoration at other mine units at Crow Butte has been similarly

prolonged:

Restoration Began Periods of Inactivity Projected

Completion

Mine Unit 3 July 1999 August 2007-May 2009 July 2013

Mine Unit 4 October 2003 August 2007-May 2009 January 2015

Mine Unit 5 August 2007 August 2007-May 2009 July 2016

The mine operator’s failure to restore groundwater within the two-year period required

in the license and NRC regulations resulted in Notices of Violation from the NRC in

September 2009.

Restoration of groundwater quality impacted by mining releases has been

similarly ineffective. In March 1996, Well I-196-5, a perimeter monitoring well, failed a

mechanical integrity test. Subsequent investigation revealed contaminated

groundwater in the upper aquifer as a result of the well failure. Remediation began in

April 1996. The operator submitted a letter in April 1998 claiming that the aquifer had

been restored and requesting an amendment to its license verifying restoration. The

NRC denied the license amendment in May 1999, stating that concentrations of sodium,

potassium, bicarbonate, sulfate, fluoride, TDS, alkalinity, arsenic, and uranium

exceeded the primary restoration goal. The issue was still open as of April 2000, with

restoration continuing. It is not clear from available information if restoration of the

upper aquifer was ever completed.

307 Feb. 24, 2004 Mine Unit 2 Groundwater Restoration Plan.

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Nebraska requires annual updates to cost estimates for financial assurance

purposes. The mine operator’s cost estimate for restoration of groundwater at the ten

mining units currently in operation or restoration phases at Crow Butte is

$18,046,416.88. That represents more than half of the amount of the mine operator’s

current financial assurance commitment of over $35 million.

8.3.2 Smith Ranch-Highland In-Situ Uranium Mine, Converse County,

Wyoming

The Smith Ranch Mine and Highland Uranium Project are located next to one

another and together cover 37,500 acres in Converse County, Wyoming. Both mines

have been jointly owned and operated since the 1980s. The mines are located in an area

of historical open pit and underground uranium mining.

8.3.2.1 A-Wellfield, Highland Mine Project

The A-Wellfield of the Highland Mine Project is located between two abandoned

uranium mines in a remote area of eastern Wyoming. Groundwater flow is toward the

flooded open pit of an abandoned uranium mine. Naturally occurring groundwater in

the area contains high levels of radium that makes it unsuitable for drinking water or

similar uses.308

From January 1988 until July 1991, the mine operator extracted uranium from the A-

Wellfield at the Highland mine site. The Groundwater Restoration Plan for the site

stated that the primary restoration goal was to return groundwater to pre-mining

conditions, on a mine unit average. If baseline conditions could not be achieved after

diligent application of the Best Practicable Technology, a secondary goal of returning

groundwater to a quality consistent with pre-mining uses was acceptable.309

Groundwater restoration began in July 1991 and continued until October 1998. Stability

monitoring for some or all of the regulated contaminants lasted from February 1999

308 A-Wellfield Completion Report (January 15, 2004).

309 Id.

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until November 2003. Both the Nuclear Regulatory Commission and the Wyoming

Department of Environmental Quality approved closure of the A-Wellfield at Highland

in 2003-04, despite the following conditions:

Concentrations at individual wells exceeded baseline conditions or

drinking water quality standards, but closure was granted because the license

required average wellfield concentrations to meet listed standards.

20 of 35 contaminants were returned to baseline, pre-mining conditions,

based on average wellfield concentrations.

11 other contaminants were reduced to drinking water standards or

below, based on average wellfield concentrations.

Average wellfield concentrations of iron, selenium, manganese and

radium exceeded drinking water standards but met industrial use standards.

Based on the mine operator’s argument that restoration to pre-mining

conditions was infeasible and uneconomical and that the affected aquifer had

been unsuitable for drinking water uses before mining, these contaminant

levels were permitted to remain.

Monitored natural attenuation was permitted to reduce certain

contaminant concentrations to levels that would not present a threat to

downgradient groundwater supplies.310

8.3.2.2 Smith Ranch Mine Project

The Nuclear Regulatory Commission issued a commercial license for in-situ leach

mining of uranium at the Smith Ranch Mine, east of Highland Mine, in March 1992.

Full-scale operations began in June 1997. By 2000, three wellfields were operable under

Wyoming Department of Environmental Quality Permit 603. Each wellfield contained

multiple mining units.311 Together, the Smith Ranch-Highland mines comprise the

largest uranium mining operation in the United States.

The mine operator submitted a groundwater restoration plan for Wellfield 1 in

October 2001. The plan’s goals were described as follows:

310 NRC Review of Groundwater Restoration Report (June 29, 2004);

311 NRC Inspection Report and Notice of Violation, at 3 (February 11, 2000).

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The objective of the reclamation plan is to return the affected surface and

groundwater to conditions such that they are suitable for all uses for

which they were suitable prior to mining. To achieve this objective, the

primary goal of the restoration program is to return the condition and

quality of the affected groundwater in a mined area to background

(baseline) or better. In the event the primary goal cannot reasonably be

achieved, the condition and quality of the affected groundwater will at a

minimum be returned to the pre-mining use suitability category

(Reference: LQD Rules and Regulations, Chapter XXI, Section 3 (d) (I)).

The mine operator made the following predictions concerning groundwater restoration,

based upon data developed during the licensing process and operation of the mine:

Restoration to primary or secondary goals would require pumping and

treatment of 6 core volumes of groundwater.

Groundwater restoration would take 10 months.

Stability sampling would require 6 months to a year.312

In 2002, the mine operator estimated that restoration costs for Wellfield # 1 would total

approximately $750,000. For the four other wellfields operating in 2002, the mine

operator estimated that restoration would require from 5 to 14 months at costs ranging

from $380,000 to over $1 million per wellfield.313 Other wellfields were subject to

similar conditions under Wyoming Permit 633.

In November 2007, the Wyoming Department of Environmental Quality

inspected the mine. In Notices of Violation issued in March 2008, the State cited the

mine operator for the following violations of Permit 603:

Operation of Wellfield C for 7 to 9 years longer than proposed in the

approved Mine Plan.

312 Wellfield # 1 Restoration Plan (October 18, 2001).

313 Application to Amend License No. SUA-1548 (February 27, 2002).

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Ongoing restoration of groundwater in Wellfield C for 10 years, instead of

the 5 years estimated in the amended operating permit.

Operation of Wellfields D and E for longer than permitted, with continued

operation at a time when both wellfields should have been in groundwater

restoration phase.

Similar violations were found for other wellfields under Permit 633, with the

agency finding that ‚actual times for uranium production and restoration are, thus far,

2-3 times longer than permit commitments.‛ The agency found that ‚groundwater

restoration is not a high priority‛ for the mine operator and that due to inadequate

restoration infrastructure, it would take at least 20 years to complete groundwater

restoration at the site. In addition, the agency noted the existence of 80 reported spills

at the mine, numerous retention ponds leaks, well casing failures and excursions,

lamenting that, ‚*u+nfortunately, it appears that such occurrences have become

routine.‛314

The agency also found that the mine operator’s financial assurance bond was

based on calculations that provided for only minimal groundwater pumping and

treatment, when much more would be needed, such that the bond was inadequate to

cover anticipated restoration costs. Furthermore, the bond calculation included

minimal funds for new infrastructure, maintenance, and repair. It also assumed a staff

of just 26 people, about half of what was required, and it allowed for salaries at levels

that were one-third too low to retain competent staff. The agency estimated that actual

reclamation costs for the site approached $150 million, but the mine operator was

bonded for a total of only $38, 416,500.315

In August 2009, the mine operator requested an extension of the groundwater

restoration deadlines for numerous wellfields. Restoration periods were projected to

range from 2 to 12 years, with some wellfields not projected to complete restoration

until 2025.316 Based on agency objections, the mine operator submitted a revised

restoration schedule recently that provides for much shorter restoration deadlines,

314 Notice of Violation (March 10, 2008).

315 Id.

316 Request for Alternate Schedule for Completion of Decommissioning (August 13, 2009).

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although it appears restoration periods will still far exceed the original projections of 5

to 14 months.317 The estimated cost of restoration increased dramatically from 2002

projections, ranging from over $500,000 to $3.1 million per wellfield.318

8.3.3 Irigaray-Christensen Ranch In-Situ Uranium Mine, Johnson County,

Wyoming

In 1977, the Wyoming Mineral Corporation (a subsidiary of Westinghouse

Electric Corporation) submitted an Environmental Assessment to the Nuclear

Regulatory Commission for full-scale operation of an in-situ leach uranium mine at the

1,000 acre Irigaray project in Johnson County, Wyoming. At the time, the county had a

population density of 1.29 people per square mile and employees had to commute to

the site from Buffalo, Wyoming, located 43 miles to the northwest. Aside from scattered

ranches (the closest of which was 3 miles away), the closest town to the site was Sussex,

Wyoming, located 15 miles away with a population of 30. At the time, the mine

operator projected a mine life of 10 years.319

A license for commercial in-situ leach uranium product was issued in August

1978. The original license permitted operations at an 800 gallon per minute flow rate,

using an ammonium bicarbonate injection solution. Due to problems with restoration

of aquifer formations mined with ammonia solutions, the mine operator changed to a

sodium bicarbonate alkaline injection solution in 1980. Operations at the Irigaray mine

ceased in 1982 due to a weak uranium market.320

In 1987, Malapai Resources Company (a subsidiary of APS) purchased the

Irigaray site and resumed operations. In 1988, permits and licenses were amended to

include the Christensen Ranch uranium mining project. Malapai ceased operations at

the Irigaray-Christensen Ranch in February 1990 and sold the project to Electricite de

France in September 1990. Operations at the site resumed in 1991. The Irigaray-

Christensen Ranch project was sold to Cogema in 1993. By 1995, mining at Irigaray has

317 Letter submitting revised restoration schedule (May 12, 2011).

318 Annual Surety Update (June 30, 2010).

319 Wyoming Mineral Corporation, Revised Environmental Report (July 29, 1977).

320 Cogema Mining Inc., Supplemental Data for Renewal Source Material License SU-1431 (December 1995).

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ceased and groundwater restoration had begun, while mining at Christensen Ranch

continued with a least one mine unit in restoration phase.321

The primary goal of groundwater restoration was to return the quality of

groundwater to baseline concentrations, using the best practicable technology and

economic reasonableness. A secondary goal was to return the aquifer quality to

conditions suitable for pre-mining uses, which were primarily livestock and agricultural

uses. An early amendment to the permits and licenses for the Irigaray project raised

restoration target values of 4 contaminants (ammonia, bicarbonate, chloride, and

uranium) above baseline, pre-mining levels because the mine operator could not restore

groundwater to baseline levels for these contaminants. Target restoration values for

Christensen Ranch were set as a baseline mean value for each contaminant with

permitted ranges of variation, again because ‚the exact average baseline value for a

particular constituent will probably not be met at restoration.‛322

Restoration of Mine Units 1 through 3 began in 1990 at the Irigaray project and

stabilization of the aquifer was demonstrated by the beginning of 1994. It was

originally projected that restoration would require processing of 7 pore volumes of

groundwater; it actually required 16 pore volumes. The mine operator was unable to

restore some contaminants in the ore-body aquifer to pre-mining levels, including total

dissolved solids and manganese. For total dissolved solids, the mine operator could not

even achieve pre-mining class of use standards, but restoration was discontinued

because continued efforts ‚would not have provided a reasonable cost benefit ratio.‛

The mine operator also was unable to restore groundwater quality in the upper aquifer

to pre-mining conditions for certain contaminants.323

Restoration of Irigaray Mine Units 4 and 5 began in 1992, was discontinued in

1994 and resumed in April 1995. Mine Units 6 through 8 began restoration in April

1995. As of December 1995, the mine operator projected that restoration at all Irigaray

mine units would be complete by 1998. The total cost of groundwater restoration for

321 Id.

322 Id.

323 Id.

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the Irigaray-Christensen Ranch project was projected to be $5,029,754.324 By 2000,

groundwater restoration cost projections had risen to $5.78 million.325

Groundwater restoration at the Irigaray project was completed and approved in

2005-06, seven years longer than projected in 1995. The mine operator was able to

restore 27 of 29 groundwater contaminants to target levels. Bicarbonate and manganese

could not be reduced to pre-mining levels, but did meet state criteria for pre-mining

uses of groundwater.326 Overall, the post-mining mean values for nearly half of the

contaminants exceeded pre-mining mean values. Restoration required processing of a

minimum of 9.5 pore volumes of groundwater per mine unit and an average of 13.7

pore volumes, or more than twice the original projection.327

At Christensen Ranch, mining in Mine Unit 2 began in 1993 and continued

through May 1997. Restoration was underway from May 1997 until March 2003,

followed by stabilization monitoring until January 2005. Restoration required

processing of over 14 pore volumes (over 393 million gallons) of groundwater. Even

then, only 24 of 35 contaminants could be reduced to target levels and 4 contaminants

(iron, manganese, uranium and radium 226) exceeded target values and federal and

state water quality standards. The exceedances were excused by the State of Wyoming

because they were deemed consistent with pre-mining uses or because it was believed

the contaminants would not migrate beyond the mining area or would naturally

attenuate.328

At Christensen Ranch Mine Unit 3, restoration required processing of 19.79 pore

volumes (over 442 million gallons) of groundwater and required over 8 years to

complete. Although restoration was approved by the State of Wyoming, only 27 of 35

contaminants reduced to target levels and 3 contaminants exceeded water quality

324 Id.

325 Cogema Mining, Inc., Annual Update to Financial Surety, License SUA-1341 (August 17, 2000).

326 Cogema Letter to NRC Requesting Concurrence in Restoration Approval (November 7, 2005).

327 Gary Janosko, NRC Review of Cogema Mining, Inc. Irigaray Mine Restoration Report (September 20, 2006).

328 Cogema Mining, Inc., Wellfield Restoration Report Christensen Ranch Project (March 5, 2008).

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standards.329 Other mine units at Christensen Ranch appear to have experienced similar

restoration conditions, although detailed data is not available.

It is not clear that restoration at Christensen Ranch has been successful. In June

2010, the NRC issued a finding that contaminant levels in at least one monitoring well

were increasing, despite the mine operator’s conclusion that the aquifer had been

stabilized.330

329 Id.

330 NRC Letter to Uranium One Americas, Inc. (June 8, 2010).

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9 Curis Has Not Complied with the Financial Capability

Demonstration Requirement for an APP.

Prior to ADEQ’s permit decision, Curis must demonstrate financial capability or

competence.331 Financial assurance must be based upon technically sound and

supported cost estimates for a number of project components. Specifically, an applicant

must provide ‚cost estimates for facility construction, operation, maintenance, closure,

and post closure‛ that are derived ‚by an engineer, controller, or accountant using

competitive bids, construction plan take-off’s, specifications, operating history for

similar facilities, or other appropriates sources, as applicable.‛332 The cost estimates,

upon which financial assurance is based, must be ‚representative of regional fair

market costs‛ for the following:333

The cost of closure under R18-9-A209(B), which requires a plan that includes

the cost of a site investigation to identify the lateral and vertical extent of soil

and groundwater contamination; contaminant sampling and analysis; fate

and transport of contaminants; and a closure design that includes treatment,

discharge control, security and monitoring methods and costs; and

The cost of post-closure monitoring and maintenance required under R18-9-

A209(C).

A vague statement that an applicant intends to provide the requisite financial

assurance is insufficient. Instead, ADEQ requires the applicant to submit information

required for at least one of the financial assurance mechanisms specified in regulation.334

And the application itself must discuss the selected mechanism or mechanisms; the

amount covered by each mechanism; the institution or company that is responsible for

each mechanism; and other details demonstrating how the applicant is financially

capable of meeting the costs described in A.A.C. § R18-9-A201(B)(5). For a letter of

credit, an applicant must meet specific regulatory criteria:

331 Ariz. Rev. Stat. § 49-243(N).

332 Ariz. Admin. Code § R18-9-A201(B)(5).

333 Ariz. Admin. Code § R18-9-A201(5)(b).

334 See Ariz. Admin. Code § R18-9-A203(C).

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the financial institution issuing the letter must be regulated by a federal or

state agency;

the letter of credit must be irrevocable and issued for at least one year in an

amount equal to the estimated cost of project construction, operation,

maintenance, closure, and post-closure activities.

the letter of credit provides that the expiration date is automatically extended

for a period of at least one year unless the issuing institution has canceled the

letter of credit by sending notice of cancellation by certified mail to the

applicant and ADEQ 90 days in advance of cancellation or expiration;335

ADEQ is the named beneficiary for the letter of credit; and

the terms of the letter satisfy certain criteria regarding term, amount, and

parties.336

Both in the Curis’s previous APP amendment application and now in the

temporary permit submittals, Curis fails to provide adequate financial assurance, a fact

which ADEQ appears to have recognized in earlier deficiency letters. According to

ADEQ’s Deficiency Letter, in its 2010 full APP application Curis failed to provide

adequate information to show that it met the financial assurance requirements of A.A.C.

§ R18-9-A203(C).337 Curis never responded to this deficiency. Instead Curis submitted

its temporary permit application, stating its ‚intention‛ to provide financial assurance

in the form of a letter of credit from a U.S. bank. Curis does not provide an actual Letter

of Credit or any correspondence from a bank indicating that Curis has actually secured

or begun to secure a Letter of Credit in the amount indicated. Instead, Curis’s Chief

Financial Officer states in a letter that the company plans to submit to ADEQ a letter of

credit from a U.S. bank.338 Again in response to ADEQ’s May Deficiency Letter, Curis

merely states without any support or elaboration that it will provide a financial

assurance mechanism satisfying the regulatory requirements.339 Curis’s financial

335 The applicant must provide alternate financial assurance within 60 days of receiving the

notice of expiration or cancellation.

336 Ariz. Admin. Code § R18-9-A203(C)(5).

337 ADEQ Deficiency Letter at 1, FD ¶3.

338 Temporary Application, at Attachment 6 at page 1(b).

339 Curis’s Response to ADEQ’s May Deficiency Letter at Item 1(m).

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assurance intentions fail to meet the statutory and regulatory criteria and should be so

recognized by ADEQ.

Make no mistake; Curis’s inadequate provision of financial assurance is a serious

deficiency that should not be ignored. It is not merely a failure to properly describe an

application component but instead should be a serious ‚red flag‛ for the agency. Curis

Resources (Arizona) is a stand-alone company and one with no previous in-situ mining

experience. Although Curis has continually touted its association with HDI, any

alleged connection with HDI is a red herring and should not be relied upon for financial

assurance purposes. HDI is not responsible for Curis’s operations or failures. Although

Curis has publicized that it is ‚associated with‛ or ‚a part of‛ the HDI group of

companies, not long ago HDI submitted a statement to Canadian securities regulators

indicating that it does not own any shares or any other interest in Curis.340 HDI is not a

‚parent‛ company that can be looked to in the event of financial difficulty. It is

important to keep in mind that there will be no recourse to HDI should Curis incur

financial hardships or cause damage to the environment or water supply. Curis is a

stand-alone company whose only asset is the Florence Copper Project. What happens

when copper prices plummet and Curis decides it is no longer economical to mine the

site? It may very well be that ADEQ and the Arizona taxpayers will have to look to

whatever financial assurance Curis provides in the event Curis abandons the mine.

Curis just recently obtained a loan through Red Kite but our review of the public

materials associated with that loan only raises more questions. Curis cannot produce

and sell enough copper during Commercial PTF operations to make the payments

required under its recent loan by the due dates. The Reclamation Plan Curis submitted

to ASLD on March 23, 2012 clearly states that the test facility will not generate

significant amounts of copper and that the copper will be stored onsite until enough is

generated to warrant a shipment.341 Therefore you cannot assume that revenues

340 HDI, Early Warning Report Under National Instrument 62-103 (July 5, 2011) (‚HDI does not

own or control any securities of Curis <HDI does not and never did own, and does not and

never did control, any of the Issuer’s issued and outstanding common shares.‛), available at

http://www.sedar.com/DisplayCompanyDocuments.do?lang=EN&issuerNo=00027268.

341 Mine Operating Plan Reclamation & Closure Plan, Production Test Facility Curis Resources

(Arizona) Inc. (March 23, 2012) at 16.

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generated from the test period will assist in the loan repayment. The loan maturity date

is May 9, 2014 with an extension to May 9, 2015 (with an increased loan rate of 13.4%

annually). An extension request will allow Curis to run the test site for 14 months to

satisfy APP and UIC permit application requirements. This gives them two months

from the end of the test phase or 14 months including the extension to get the mine

operational and generate several million pounds of copper just to avoid defaulting on

the loan – a feat which appears to defy common sense. We question how Curis plans to

repay the huge loan from Red Kite if the mine won’t be fully operational until mid-2014.

Furthermore, if they default by not repaying the loan by May 2015, then Red Kite—a

financing company, not a mine operator—can take the Curis assets as collateral. We

question what will happen to the closure, reclamation, post-closure, and mining

operations when the property is assumed by Red Kite.

Curis has failed to meet the financial demonstration requirements for an APP

permit. For this reason alone, ADEQ should deny the requested permit.

9.1 Regularly updated and re-evaluated costs are key.

Curis should be required to provide updated cost information annually for the

Commercial PTF. Many of the Commercial PTF’s key details, standards and

requirements will not be known until after permits are issued, if Curis’s proposal is

accepted. For instance:

ALs and AQLs will be set after the Temporary APP is issued;

Wells and coreholes will be abandoned after the UIC and APP permits are

issued; and

Details regarding closure and reclamation will not be produced until the PTF

operations are done.

As you know, we believe all of these issues should be addressed before any permits are

issued. But if Curis’s proposal is accepted, the costs associated with the Commercial

PTF could change dramatically, based on how these and other issues are addressed.

This warrants annual review of cost estimates and adjustments to the financial

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assurance mechanism as necessary to ensure closure and reclamation costs are

addressed.

9.2 Curis Should Provide Up-Front Financial Assurance Mechanisms

and Contingencies to Address Off-Site Contamination.

Nothing in Curis’s financial assurance proposals will address off-site

contamination, injury to neighboring landowners’ property rights and property values,

or impacts to human health and the environment. We assume that Curis will argue

ADEQ has no authority to include such considerations in determining costs to be

covered by financial assurance. We believe ADEQ has ample authority and discretion

to address these issues through the financial assurance requirements. At the very least,

ADEQ should require Curis to develop a mitigation plan for addressing offsite impacts

from ISL mining. If the Temporary APP permit is issued, Curis will be effectively

permitted to pollute Florence’s drinking water supply. At a minimum, Curis should be

required to address the risks posed to the Town’s drinking water now, not after

contaminants have escaped Curis’s control and done their damage.

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10 ADEQ Should Carefully Scrutinize Curis’s Predictions

of Environmental Safety.

As ADEQ is well aware, Arizona is riddled with abandoned, closed, and

still-operating mine sites that have contaminated surface waters, groundwater,

and soils. Many sites continue to pollute today, despite modern environmental

standards and permit requirements. Curis’s rosy predictions that nothing can or

will go wrong and that Florence’s drinking water supply will not be impacted by

this mine ignore the fact that most, if not all mines in this State have and will

create pollution that must be dealt with. Indeed, the very process of ISL mining

purposefully pollutes groundwater in order to extract copper.

In 2006, environmental experts issued two reports on the mining

industry’s ability to predict impacts to surface water and groundwater. The first,

Predicting Water Quality at Hardrock Mines, examined modern methods for

modeling and predicting impacts based on geochemical characterization

techniques. The second, Comparison of Predicted and Actual Water Quality at

Hardrock Mines, surveyed data from 25 mines around the country to determine

the reliability of predictions made by mining companies concerning the impacts

of their operations. These reports reviewed copper mines and other types of

hardrock mines in ten western states, including Arizona. These first-of-their-

kind reports were peer reviewed by experts in the private sector, as well as by

the United States Geological Survey and USEPA.

These studies bring to light a decades-long failure by Government

regulators and industry consultants to recognize and correct deficient procedures

and methods for predicting contamination of water at hardrock mines. As a

result of this failure, faulty analysis continues to support predictions of water

quality impacts that are painting a false picture for the public. The reports

provide numerous findings that should be considered in evaluating Curis’s

claims regarding the impacts of this mine.

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The studies conclude that, despite predictive modeling, the problems at

the vast majority of mines were worse than predicted. Predictions failed

because, among other things, mining companies failed to adequately characterize

site conditions; water quality predictions were biased to minimize predicted

impacts; and there is little or no field information describing the impacts of

hydrogeologic conditions, weather and other factors on contaminant movement

in the environment. Similarly, Curis’s promise that ISL mining presents no risks

to the environment is based on faulty analysis, a failure to consider key facts, and

an overly-optimistic prediction of operational impacts. Every mine carries risks,

but Curis adamantly fails to recognize such risks or address them.

All of the mining companies that were studied predicted that their mines

would operate in full compliance with water quality standards. Operating data,

however, indicated that 76% of the mines exceeded water quality standards due

to mining activity. Of the mines studied, 52% produced groundwater

contamination that exceeded water quality standards. These statistics do not

support Curis’s claims that their operations pose no risks.

Toxic heavy metals (lead, mercury, cadmium, copper, zinc and others)

exceeded standards at 63% of the mines studied. Arsenic and sulfate exceeded

standards at 58% of the mines. Cyanide exceeded standards at 53% of the mines.

For Curis to project that the injection and stacking of acid leaching solutions,

which will contain high concentrations of these and other contaminants, will not

result in groundwater contamination is completely unrealistic.

Mitigation measures predicted to prevent violations of water quality

standards failed at 64% of the mines studied. Twenty-two of 25 mines exceeded

groundwater quality standards despite predictions that mitigation would result

in compliance. The other three mines did not even predict a need for mitigation.

The only measure proposed by Curis to prevent contaminated copper leaching

solutions from flowing in drinking water aquifers is hydraulic control through

perimeter wells and aquifer rinsing at mine closure. Similar efforts have failed at

every other in-situ leach mine in the United States.

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Long term water treatment is often the single most significant cost

associated with mining clean up. This is clearly the case with the Florence

Copper Project, where groundwater cleanup costs could be tens of millions of

dollars. While most major mine operators are required to post financial

assurance before mining begins, these financial assurance mechanisms are based

upon predictions of reclamation costs that are founded on faulty predictions of

water quality impacts. The report recommends reassessing the adequacy of the

financial assurances provided by mine operators to guarantee mining cleanup is

paid for. We believe a careful assessment of Curis’s financial assurance proposal

is needed, as the proposal is based on inaccurate and incomplete cost

information and because Curis appears determined to rely on a risky financial

assurance mechanism such as insurance.

Predicted water quality impacts do not match reality, particularly where

mines were located in close to high-risk water resources. Ninety-three percent of

mines near groundwater with elevated potential for acid drainage or

contaminant leaching exceeded water quality standards; 85% of the mines near

surface water with similar potential exceeded water quality standards. The

report suggests additional regulatory scrutiny needs to be given to the highest

risk proposals—defined as mines near water resources and with elevated acid

drainage or contaminant leaching potential. We believe the Florence Copper

Project, which will use acid leaching in underground aquifers to extract copper,

is a high-risk project with elevated potential for contaminant leaching. It

deserves close scrutiny by the public and environmental regulators.

Despite the known impacts of mining in this country, the models,

analysis, and predictions regarding mining operations are never revisited by the

mining industry, regulators, or mining consultants to determine how accurate

predictions and models were or to refine techniques and methods. In a similar

vein, Curis is premising its permit applications on a 15-year pilot project

operated for a few weeks by a former mine owner, offering to conduct further

investigation only after the permits are issued.

In sum, the errors and omissions that have led to decades of

environmental pollution from mining practices stand to be replicated in the

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permitting of Curis’s mine if significant changes are not required of Curis’s

proposals.

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