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Licence: L9190/2019/1

IR-T04 Decision Report Template v2.0 (July 2017) i

Application for Licence

Division 3, Part V Environmental Protection Act 1986

Licence Number L9190/2019/1

Applicant

Kundana Gold Pty Ltd

ACN 009 643 252

File Number 2012/006664

Premises Kundana Gold Pty Ltd

Legal description -

Mining tenements M16/72, M16/73, M16/87, M16/97,

M16/157, M16/308, M16/309, M15/669, M15/993, M16/428,

M24/924, L16/39, L16/105 and L16/106

KALGOORLIE WA 6430

As defined by the map in Schedule 1 of the Licence

Date of Report 30 January 2019

Status of Report Final

Decision Report

1 Licence:L9190/2019/1

IR-T04 Decision Report Template v2.0 (July 2017)

Table of Contents 1. Definitions of terms and acronyms ................................................................... 2

2. Purpose and scope of assessment ................................................................... 4

3. Background ......................................................................................................... 4

4. Overview of Premises......................................................................................... 4

4.1 Operational aspects ............................................................................................... 4

5. Legislative context.............................................................................................. 5

5.1 Part V of the EP Act ............................................................................................... 5

Applicable regulations, standards and guidelines ............................................ 5

Works approval and licence history ................................................................. 5

6. Location and siting ............................................................................................. 6

6.1 Siting context .......................................................................................................... 6

6.2 Residential and sensitive Premises ........................................................................ 6

6.3 Specified ecosystems ............................................................................................. 7

6.4 Groundwater and water sources ............................................................................. 7

7. Risk assessment ................................................................................................. 8

7.1 Determination of emission, pathway and receptor .................................................. 8

7.2 Consequence and likelihood of risk events ........................................................... 11

7.3 Acceptability and treatment of Risk Event ............................................................. 12

7.4 Risk Assessment – Mine dewatering to White Flag Lake ...................................... 12

Description of mine dewatering to White Flag Lake ....................................... 12

Description of potential adverse impact from the emission ............................ 12

Criteria for assessment.................................................................................. 13

Licence Holder controls ................................................................................. 15

Consequence ................................................................................................ 15

Likelihood of Risk Event ................................................................................ 15

Overall rating of dewatering discharge to White Flag Lake ............................ 16

8. Determination of Licence conditions .............................................................. 16

9. Applicant’s comments ...................................................................................... 16

10. Conclusion ........................................................................................................ 16

Appendix 1: Key documents .................................................................................... 17

Appendix 2: Summary of applicant’s comments on risk assessment and draft conditions .................................................................................................................. 18

Attachment 1: Issued Licence L9190/2019/1 ........................................................... 20

Table 1: Definitions ................................................................................................................ 3

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1. Definitions of terms and acronyms In this Decision Report, the terms in Table 1 have the meanings defined.

Table 1: Definitions

Term Definition

AACR Annual Audit Compliance Report

ACN Australian Company Number

AER Annual Environment Report

Category/ Categories/ Cat.

Categories of Prescribed Premises as set out in Schedule 1 of the EP Regulations

CS Act Contaminated Sites Act 2003 (WA)

Decision Report refers to this document.

Delegated Officer an officer under section 20 of the EP Act.

Department means the department established under section 35 of the Public Sector Management Act 1994 and designated as responsible for the administration of Part V, Division 3 of the EP Act.

DWER Department of Water and Environmental Regulation

As of 1 July 2017, the Department of Environment Regulation (DER), the Office of the Environmental Protection Authority (OEPA) and the Department of Water (DoW) amalgamated to form the Department of Water and Environmental Regulation (DWER). DWER was established under section 35 of the Public Sector Management Act 1994 and is responsible for the administration of the Environmental Protection Act 1986 along with other legislation.

EPA Environmental Protection Authority

EP Act Environmental Protection Act 1986 (WA)

EP Regulations Environmental Protection Regulations 1987 (WA)

EPBC Act Environment Protection and Biodiversity Conservation Act 1999 (Cth)

Existing Licence The Licence issued under Part V, Division 3 of the EP Act and in force prior to the commencement of, and during this Review

Licence Holder Kundana Gold Pty Ltd

mᶟ cubic metres

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Minister the Minister responsible for the EP Act and associated regulations

mtpa million tonnes per annum

Noise Regulations Environmental Protection (Noise) Regulations 1997 (WA)

Occupier has the same meaning given to that term under the EP Act.

Prescribed Premises

has the same meaning given to that term under the EP Act.

Premises refers to the premises to which this Decision Report applies, as specified at the front of this Decision Report

Primary Activities as defined in Schedule 2 of the Revised Licence

Risk Event As described in Guidance Statement: Risk Assessment

UDR Environmental Protection (Unauthorised Discharges) Regulations 2004 (WA)

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2. Purpose and scope of assessment This Licence replaces previous licence L7323/1998/12. DWER has not carried out a new risk assessment for this Licence.

3. Background Table 2 lists the prescribed premises categories that have been applied for.

Table 2: Prescribed Premises Categories in the Existing Licence

Classification of Premises

Description Approved Premises production or design capacity or throughput

Category 5

Processing or beneficiation of metallic or non-metallic ore: premises on which —

(a) metallic or non-metallic ore is crushed, ground, milled or otherwise processed; or

(b) tailings from metallic or non-metallic ore are reprocessed; or

(c) tailings or residue from metallic or non-metallic ore are discharged into a containment cell or dam.

850 000 tonnes per year

6 Mine dewatering: premises on which water is extracted and discharged into the environment to allow mining of ore.

12 000 000 tonnes per annual period

12 Screening etc. of material; premises (other than premises within category 5 or 8) on which material extracted from the ground is screened, washed, crushed, ground, milled, sized or separated.

500 000 tonnes per year

52 Electric power generation: premises on which electrical power is generated using a fuel.

15.65 MW

89

Putrescible landfill site: premises on which waste (as determined by reference to the waste type set out in the document entitled “Landfill Waste Classification and Waste Definitions 1996 (As amended December 2009)” published by the Chief Executive Officer and as amended from time to time) is accepted for burial.

5 000 tonnes per annual period

4. Overview of Premises

4.1 Operational aspects Kundana Gold Pty Ltd (Kundana) is a gold mining company with its primary business purpose being the mining of gold ore from open pits and underground mines. The site is a prescribed premise due to the following activities:

Mine dewatering operations, with discharge into various void pits and to White Flag Lake;

Crushing and screening to pre-treat ore prior to transport offsite for processing and to use process waste rock into road base;

Electric power generation; and

Putrescible landfill

Prior to 2004, Kundana operated a gold mill which was licenced under category 5 of the

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Environmental Protection Regulations 1987. In March 2004, the mill was placed in care and maintenance and consequently the category was removed from the licence. Monitoring of groundwater, however, is still on the licence in relation to inactive tailings storage facilities (TSF) 1, 2 and 3.

Kundana is licenced to discharge water from mine dewatering to White Flag Lake (one of a number of salt lakes in the Goldfields region used for this type of discharge) and this includes discharge from the Kundana site (Raleigh underground mine and various other open pits) as well as dewatering discharge from the Mungari Gold Project that Kundana manages via an agreement with La Mancha Resources Australia Pty Ltd. The project was referred to the EPA by Kundana in 2003, but was not formally assessed and was recommended to be managed under Part V of the Environmental Protection Act 1986.

Mine dewater is pumped via pipelines from the Kundana mining operations and the Mungari Gold Projects. The mine dewater is generally hypersaline at >100 000mg/L total dissolved solids (TDS) and is either reused in mining and ancillary operations, stored in pits or at the transfer dam prior to being discharged to White Flag Lake.

The White Flag Lake Water transfer system has been designed to facilitate flexibility with regards to dewatering activities associated with the Kundana and Mungari operations.

5. Legislative context

5.1 Part V of the EP Act

Applicable regulations, standards and guidelines

The overarching legislative framework of this assessment is the EP Act and EP Regulations.

The guidance statements which inform this assessment are:

Guidance Statement: Regulatory Principles (July 2015)

Guidance Statement: Setting Conditions (October 2015)

Guidance Statement: Licence Duration (August 2016)

Guidance Statement: Publication of Annual Audit Compliance Reports (May 2016)

Guidance Statement: Decision Making (February 2017)

Guidance Statement: Risk Assessments (February 2017)

Guidance Statement: Environmental Siting (November 2016)

Works approval and licence history

Table 3 summarises the works approval and licence history for the premises since 5 January 2004.

Table 3: Works approval and licence history

Instrument Issued Nature and extent of works approval, licence or amendment

L7323/1998/7 05/01/2004 Licence re-issue

W3973/1998/1 24/05/2004 Category 6 and 64 works approval

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W4101/1998/1 18/03/2005 Category 6 and 64 works approval




L7323/1998/12 19/12/2013 Licence re-issue and amendment to new REFIRE format

L7323/1998/12 08/01/2015 Licence amended for administrative errors

L7323/1998/12 26/11/2015 Licence amended to include new landfill cell

L7323/1998/12 15/12/2016 Amendment Notice 1 – to amend the premises address and to include new dewatering discharge points

L7323/1998/12 05/05/2017 Amendment Notice 2 – to include the construction of the Millennium landfill cell.

L7323/1998/12 17/11/2017 Amendment Notice 3 – to include category 52, confirm Millennium landfill compliance report and include operational conditions.

L7323/1998/12 05/02/2018 Amendment Notice 4 – to include categories 5 and 12 to the Licence and permit crushing and screening of ore to a rate of 850 000 tpa and crushing and screening of waste rock at a rate up to 500 000 tpa.

L9190/2019/1 31/01/2019 New licence to replace L7323/1998/12. No new risk assessment has been carried out.

6. Location and siting

6.1 Siting context Kundana is located approximately 25 kilometres (km) west north-west of Kalgoorlie on mining tenements M16/72, M16/73, M16/87, M16/97, M16/157, M16/308, M16/309, M15/669, M15/993, M16/428, M24/924, L16/39, L16/105 and L16/106. The area is part of the Coolgardie Biosphere characterised by eucalypt woodlands overlying Archaean greenstone rocks with red-brown sandy soils and loams. The natural drainage through the Kundana site is in a north-east to easterly direction towards White Flag Lake.

6.2 Residential and sensitive Premises The distances to residential and sensitive receptors are detailed in Table 4.

Table 4: Receptors and distance from activity boundary

Sensitive Land Uses Distance from Prescribed Activity

Kurrawang Community Located 15.65 km south east of Kundana Operations

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6.3 Specified ecosystems The area surrounding the prescribed activity contains no recorded rare or threatened flora, fauna or ecological communities.

6.4 Groundwater and water sources The distances to groundwater and water sources are shown in Table 5.

Table 5: Groundwater and water sources

Groundwater and water sources Distance from Premises Environmental value

Public drinking water source areas There are no public drinking water sources near the area.

N/A

Major watercourses/waterbodies White Flag Lake approximately 5 km north of the Premises.

White Flag Lake is an ephemeral salt lake which supports a range of aquatic organisms and avifauna particularly following a period of rainfall.

Groundwater The pre-mining water table was between 5 and 20 mbgl. However, this has been significantly lowered by mining and water levels in the project area are now between 10 and 43 mbgl.

The quality of the groundwater is hypersaline with total dissolved solids ranging from 146 000 to 261 000 mg/L.

Water use within the vicinity of the area is for mining use only. There are no known groundwater dependent ecosystems in the area.

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7. Risk assessment

7.1 Determination of emission, pathway and receptor In undertaking its risk assessment, DWER will identify all potential emissions pathways and potential receptors to establish whether there is a Risk Event which requires detailed risk assessment.

To establish a Risk Event there must be an emission, a receptor which may be exposed to that emission through an identified actual or likely pathway, and a potential adverse effect to the receptor from exposure to that emission. Where there is no actual or likely pathway and/or no receptor, the emission will be screened out and will not be considered as a Risk Event. In addition, where an emission has an actual or likely pathway and a receptor which may be adversely impacted, but that emission is regulated through other mechanisms such as Part IV of the EP Act, that emission will not be risk assessed further and will be screened out through Table 6.

The identification of the sources, pathways and receptors to determine Risk Events are set out in Table 6 below.

Table 6: Identification of emissions, pathway and receptors during operation

Risk Event

Consequence rating

Likelihood rating

Risk Reasoning Source/Activities Potential emissions

Potential receptors

Potential pathway Potential adverse impacts

Category 5

Processing or beneficiation of metallic or non-metallic ore

Category 12 Screening of material

operation of crushing and screening infrastructure

Dust: conveyor transport of ore, crushing and screening

No residences or other sensitive receptors in proximity.

The nearest resident to the Kundana Gold Operation is the Kurrawang Community, located greater than 15 km to the south-east.

Air/wind dispersal Potential amenity and health impacts

N/A N/A N/A The separation distance of greater than 15 km between the source and the receptors is adequate. No material risk present during installation or operation.

Additionally dust suppression sprays, bars and nozzles will be used within the mobile plant to minimise dust. Where appropriate the Licence Holder has proposed to install dust covers on the plant.

Noise: operation of crushers, screens


N/A N/A N/A The separation distance of greater than 15 km between the source and the receptors is adequate to mitigate noise emissions; therefore no material risk is present during installation or operation.

Sediment contaminated stormwater: elevated metals in sediment transported off Premises

White Flag Lake is a salt lake located approximately 4 km from the location of the landfill. This is the nearest surface water body to the Premises.

There is also a claypan located approximately 500m to the south east of the proposed mobile crushing and screening plant

Runoff via sheet flow, drainage channels

Flow is in an easterly direction

Adverse downstream water quality in clay pans to the south or east

Slight Unlikely Low The mobile plant will be located within a bunded area. This control will be conditioned.

It is noted that there is considerable existing mining disturbance (open pits to the west and east, cleared areas) in the immediate area, mitigating the likelihood that contaminated stormwater would reach the claypan system to the east.

Category 6

Mine dewatering

Discharge of mine water into the following pits:

-Kurrawang

-Pope John

-South

Dust: associated with operational activities

The nearest resident to the Kundana Gold Mine is the Kurrawang Community, approximately 15 km south-east.

Air: Particulate matter (fugitive dust)

Dust can potentially result in health or amenity impacts to humans

N/A N/A N/A The Delegated Officer considers the material risk of dust emissions from the operation dewatering pipelines to remain low, due to the distance to the nearest sensitive receptor.

The substantive offenses of the Environmental Protection Act 1986 provide enforceable prohibitions for dust emissions that result in pollution or environmental harm.

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-Arctic/North

-Barkers

-Barkers North

-Moonbeam

Noise: associated with operational activities

Air: Noise generated by the operation of equipment

Amenity impacts to any nearby noise sensitive receptors

N/A N/A N/A The Delegated Officer notes the lack of nearby sensitive receptors and determines that there is no risk of noise impact.

Waste: Hypersaline water will be transported in pipelines and has the potential to be emitted if the pipelines were to leak or rupture

Surrounding vegetation

Land: infiltration through soil profile and direct inundation of vegetation

Contamination of surrounding land with hypersaline water, causing vegetation stress or vegetation deaths.

Moderate Unlikely Medium The Licence Holder has committed to installing all pipelines above ground or suitably buried and will utilise suitably designed containment structure/bunding to contain any potential leaks or spills. They have also stated that appropriate inspection regimes will be carried out on the pipelines.

Based on the Licence Holder controls, the Delegated Officer considers that the consequence would be moderate and the likelihood is unlikely. Therefore the risk rating for pipeline spills is medium.

The Delegated Officer is satisfied that existing conditions on the Licence relating to pipeline management will be sufficient to manage the new pipelines.

Waste: Potential mounding of the water table in the vicinity of the receiving pits

Surrounding vegetation

Groundwater: subsurface lateral movement of pit lake water to groundwater table

Potential impacts to adjacent vegetation through inundation of roots.

Moderate Rare Medium A hydrogeological investigation showed that regional groundwater flow direction is east towards major palaeochannels, and the ephemeral lakes and salt pans. The pre-mining water table was between 5 and 20 mbgl. However, this has been significantly lowered by mining and water levels in the project area are now between 10 m and 43 mbgl.

The study also showed that the surrounding geology has naturally low permeability which will limit seepage into the surrounding groundwater, even if the pit lake levels rise above groundwater table levels.

The quality of the groundwater is hypersaline with total dissolved solids ranging from 146,000 to 261,000 mg/L. Groundwater use within the vicinity of the mine is other mining operations.

There are no known groundwater dependent ecosystems in the area. Previous studies have presumed a 6 m rooting depth limit of vegetation. The Licence Holder has committed to ensuring the pit water levels are kept at a minimum of six mbgl.

As there have been no adverse impacts observed for the pits currently licenced for groundwater storage and given the level of controls in place by the Licence Holder, the Delegated Officer considers that the consequence would be moderate and the likelihood is rare. Therefore the risk rating for groundwater mounding is medium.

A pit lake limit condition of 6 mbgl exists on the Licence, which formalises the Licence Holder’s commitment and will ensure surrounding vegetation is protected.

Discharge of mine water to White Flag Lake

Waste: hypersaline water from underground mine discharged to the surface of White Flag Lake

Impacts to the lake include increase in salt load, change in hydro-period and bankside erosion. Potential to have long term effects on productivity of salt lakes and the flow on effect to avifauna which rely on lake biota

Moderate Possible Medium See section 8.4 for full assessment detail

Category 52

Electric power generation

Operation of Kundana and Barkers power stations


The nearest resident to the Kundana Gold Mine is the Kurrawang


N/A N/A N/A There to be no material risk of dust, noise and air emissions from the operation of power station, due to the distance to the nearest sensitive receptor.

The substantive offenses of the Environmental Protection Act 1986 provide enforceable prohibitions for dust emissions that result in pollution or Noise: associated

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with operational activities

Community, approximately 15 km south-east.

environmental harm.

Noise emissions are expected to comply with the Environmental Protection (Noise) Regulation 1997.

New condition 3.5 will be included to ensure both PSs process outputs are recorded and provided in the annual report.

Air emissions:

associated with burning of diesel fuels

Waste: associated with hydrocarbon leaching to groundwater

Groundwater in the vicinity of the premises is at least 10 mbgl.


Potential impact to groundwater

N/A N/A N/A There will be no material risk of hydrocarbon leaching to groundwater due to the depth of groundwater beneath the power stations.

Waste: associated with hydrocarbon run-off to surface water

White Flag Lake is a salt lake located approximately 4 km from the location of the landfill. This is the nearest surface water body to the premises.

Water: contaminated surface water run-off

Water: contaminated surface water run-off

N/A N/A N/A Due to the 5 km distance between White Flag Lake and the power stations DWER considers there is no material risk associated with hydrocarbon associated with surface water run-off.

Existing licence conditions require management actions to contain and remediate spills and leaks therefore preventing discharges. Existing licence conditions adequately address this risk.

Category 89

Putrescible landfill

Operation of landfill cells (Millennium, Raleigh and Rubicon)


The nearest resident to the Kundana Gold Mine is the Kurrawang Community, approximately 15 km south-east.


N/A N/A N/A The Delegated Officer considers there to be no material risk of dust or noise emissions from the operation of the landfill, due to the distance to the nearest sensitive receptor.

The substantive offenses of the Environmental Protection Act 1986 provide enforceable prohibitions for dust and noise emissions that result in pollution or environmental harm. Noise: associated

with operational activities

Waste: associated with leachate to groundwater

Groundwater - Groundwater in the vicinity of the premises ranges from 10 to 40 mbgl.


Contamination of groundwater which could impact on any groundwater dependent ecosystems

N/A N/A N/A The Delegated Officer considers there to be no material risk of leachate to groundwater from the landfill, due to the location of the landfill on the waste rock dump and the depth of groundwater.

Waste: associated with run-off

White Flag Lake is a salt lake located approximately 4 km from the location of the landfill. This is the nearest surface water body to the premises.

Land: contaminated surface run-off

Contamination of surrounding ecosystems and water ways.

N/A N/A N/A Due to the distance between White Flag Lake and the landfill being 4 km the Delegated Officer considers there is no material risk associated with waste associated with run-off.

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7.2 Consequence and likelihood of risk events A risk rating will be determined for risk events in accordance with the risk rating matrix set out in Table 7 below.

Table 7: Risk rating matrix Likelihood Consequence

Slight Minor Moderate Major Severe

Almost certain Medium High High Extreme Extreme

Likely Medium Medium High High Extreme

Possible Low Medium Medium High Extreme

Unlikely Low Medium Medium Medium High

Rare Low Low Medium Medium High

DWER will undertake an assessment of the consequence and likelihood of the Risk Event in accordance with Table 8 below.

Table 8: Risk criteria table Likelihood Consequence

The following criteria has been used to determine the likelihood of the Risk Event occurring.

The following criteria has been used to determine the consequences of a Risk Event occurring:

Environment Public health* and amenity (such as air and water quality, noise, and odour)

Almost Certain

The risk event is expected to occur in most circumstances

Severe onsite impacts: catastrophic

offsite impacts local scale: high level or above

offsite impacts wider scale: mid-level or above

Mid to long-term or permanent impact to an area of high conservation value or special significance^

Specific Consequence Criteria (for environment) are significantly exceeded

Loss of life Adverse health effects: high level or

ongoing medical treatment

Specific Consequence Criteria (for public health) are significantly exceeded

Local scale impacts: permanent loss of amenity

Likely The risk event will probably occur in most circumstances

Major onsite impacts: high level

offsite impacts local scale: mid-level

offsite impacts wider scale: low level

Short-term impact to an area of high conservation value or special significance^

Specific Consequence Criteria (for environment) are exceeded

Adverse health effects: mid-level or frequent medical treatment

Specific Consequence Criteria (for public health) are exceeded

Local scale impacts: high level impact to amenity

Possible The risk event could occur at some time

Moderate onsite impacts: mid-level

offsite impacts local scale: low level

offsite impacts wider scale: minimal

Specific Consequence Criteria (for environment) are at risk of not being met

Adverse health effects: low level or occasional medical treatment

Specific Consequence Criteria (for public health) are at risk of not being met

Local scale impacts: mid-level impact to amenity

Unlikely The risk event will probably not occur in most circumstances

Minor onsite impacts: low level

offsite impacts local scale: minimal

offsite impacts wider scale: not detectable

Specific Consequence Criteria (for environment) likely to be met

Specific Consequence Criteria (for public health) are likely to be met

Local scale impacts: low level impact to amenity

Rare The risk event may only occur in exceptional circumstances

Slight onsite impact: minimal

Specific Consequence Criteria (for environment) met

Local scale: minimal to amenity

Specific Consequence Criteria (for public health) met

^ Determination of areas of high conservation value or special significance should be informed by the Guidance Statement: Environmental Siting. * In applying public health criteria, DWER may have regard to the Department of Health’s Health Risk Assessment (Scoping) Guidelines.

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“onsite” means within the Prescribed Premises boundary.

7.3 Acceptability and treatment of Risk Event DWER will determine the acceptability and treatment of Risk Events in accordance with the Risk treatment table 9 below:

Table 9: Risk treatment table

Rating of Risk Event

Acceptability Treatment

Extreme Unacceptable. Risk Event will not be tolerated. DWER may refuse application.

High May be acceptable.

Subject to multiple regulatory controls.

Risk Event may be tolerated and may be subject to multiple regulatory controls. This may include both outcome-based and management conditions.

Medium Acceptable, generally subject to regulatory controls.

Risk Event is tolerable and is likely to be subject to some regulatory controls. A preference for outcome-based conditions where practical and appropriate will be applied.

Low Acceptable, generally not controlled.

Risk Event is acceptable and will generally not be subject to regulatory controls.

7.4 Risk Assessment – Mine dewatering to White Flag Lake

Description of mine dewatering to White Flag Lake

Mine dewatering water is pumped via pipeline to disused pits, currently the Kurrawang, Pope John, Arctic/North, Barkers, Barkers North, Moonbeam and South pits as required. Water is then pumped directly to White Flag Lake (6km). Water is hypersaline at >100,000mg/L TDS.

Description of potential adverse impact from the emission

The long term effects of discharging large volumes of hypersaline dewatering water to ephemeral salt lakes such as White Flag Lake are largely unknown, as this practice has only been occurring in the Goldfields region of Western Australia for the last 20 years. However the effects of the discharge can be managed via proper construction of the discharge point and implementing actions following monitoring of the effects of the discharge on the lake and fringing environments. This monitoring allows for action to be undertaken should detrimental effects be identified. Three key areas have been identified:

prevention of erosion at the discharge point;

ensuring fringing areas of the lake are not significantly affected by inundation or salt spray from hypersaline water discharge; and

monitoring of the lake surface to gain an understanding of the effect of the discharge.

If discharge points are not managed correctly they will have high velocity water entering a sand/ gravel/ clay based strata. The high energy of the discharge water will conceivably encourage the entrainment of sediment and erosion of the lakebed. Without a suitably constructed and maintained discharge point this represents a significant risk. By placing a box around the discharge point with rubber matting to cushion the impact of the high velocity water

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onto the lake bed (Photo 1) the risk is considered minimal and therefore monitoring is considered an appropriate regulatory requirement.

Photo 1: Discharge Point

The discharge of hypersaline waters to the lake bed increases the available water and its residence time in the lake. If these waters pond near the lake edges they have the potential to cause the death of fringing vegetation. Pipelines and the discharge point should be constructed in such a manner that as far as possible prevents ponding occurring. Vegetation may also be affected via increase in salt-laden winds from the hypersaline waters and via the increased salt load inhibiting the germination of new-plants.

The shoreline of saline ephemeral lakes such as White Flag Lake are a naturally harsh environment thus monitoring is required to determine if plant deaths are related to natural causes or from the influence of mining (dewater discharge).

The known effects of hypersaline water discharge to the bed of ephemeral salt lakes includes increase in salt load, change in hydro-period and increase in salinity during episodic rainfall events, which may affect the breeding cycles of lake biota. It is unknown at this stage if these discharges will have long term effects on the productivity of the salt lakes and the flow on effects to avifauna which rely on lake biota. Monitoring is important in determining these long term effects and assessing the risks involved.

Criteria for assessment

Ecological assessment to date has not shown any adverse environmental impacts related directly to dewatering discharge to White Flag Lake. However monitoring has only been carried out since 2000, which is considered insufficient time to assess the long-term impact. Investigations to date have shown some increase in the salinity of the shallow lake sediments as a result of the dewatering discharge and consequent salt crust formation. An estimate of the salt inflows from the dewatering discharge gives an indication of the potential impacts of the dewatering discharge salt load on the lake system. To measure salt load, the volume of water discharged and TDS concentrations need to be measured regularly. Thus a licence condition requiring the recording of monthly cumulative volumes of mine dewater discharged to White Flag Lake is added. TDS is covered under sampling below.

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Due to the mining of naturally mineralised rock, there is some risk of metal loadings in the discharge. Natural levels of metals in the lake are low. However, arsenic up to 0.4mg/L, iron up to 1mg/L, nickel up to 1.4mg/L and zinc up to 0.6mg/L have been recorded in the discharge waters from time to time with corresponding elevations in the natural surface waters. To date there is limited data and research literature available on the effects of elevated metals contents in the salt lake environment. However, the similarity in ionic ratios (Na+>Mg+>Ca+>K+ and Cl->SO4

2->HCO32-) of salt lakes and seawater suggest the salts are of marine origin

(DeDeckker 1983). Thus potential trigger values could be attained from marine waters, used at 95% level of protection based on the National Water Quality Management Strategy (NWQMS) – “Australian and New Zealand Guidelines for Fresh and Marine Water Quality 2000”.

Metal Typical recorded value

Highest recorded value

Trigger value

Arsenic 0.015 0.04 Not identified

Cadmium <0.050 <0.050 0.055

Chromium <0.500 <0.500 0.274

Copper <0.500 <0.500 0.013

iron <0.500 1 Not identified

Lead <0.500 <0.500 0.044

nickel <0.500 1.4 0.7

zinc <0.500 0.6 0.15

* all values are in mg/L

As can be seen from the table above the highest nickel and zinc values recorded are above the trigger levels identified for 95% species protection in marine waters. Trigger levels for iron and arsenic have not been identified as there is insufficient data. Detection levels for cadmium, chromium, copper and lead are above the trigger values thus of little use.

The behaviour of potential toxic metals such as copper, lead, nickel and zinc in ephemeral hypersaline waterways such as White Flag Lake is poorly studied. The Australian Centre for Mineral Environmental Research (ACMER) – “Review of Methods for water Quality Assessment of Temporary Stream and Lake Systems” stated that the NWQMS trigger values provided above are based on steady state conditions that by definition do not occur in temporary waters such as White Flag Lake. The concentration of a toxicant that can cause detrimental impact in ephemeral hypersaline waterways may be higher than would be expected for long-term exposure, as indicated by the NWQMS trigger values.

Therefore, the current strategy for managing the impact of mine dewatering water on White Flag Lake is to monitor the lakes in order to determine appropriate trigger levels.

Salinity, pH and ionic dominance are the main tools used for comparison and identification of salt lakes. Thus it is recommended that Kundana monitors these parameters at the discharge point and/or pipeline pump station.

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The strategy for managing the risks associated with rising groundwater levels around the pits used for dewatering discharge is to ensure the licensee undertakes suitable and sufficient monitoring to determine the impact of rising ground water levels. Ground water levels shallower than 4 m from the surface are considered more likely to cause the deaths of trees surrounding the pits. Kundana has indicated that it would prefer to manage the surrounding groundwater levels conservatively within the Kurrawang, Pope John or South pits by monitoring the level of water in pits rather than install and monitor groundwater monitoring bores around the pits. DWER considers that should groundwater mounding occur around the pits that this mounding will occur below the depth of water in the pits. Therefore if water levels in the pits remain at depths greater than 6 m below the natural surface then by default groundwater levels will also remain less than 6 m.

DWER considers that a 6 m trigger is appropriate for the type of monitoring Kundana has elected to undertake. This allows Kundana enough time to prevent groundwater levels reaching 4 m below surface via the design and implementation of a groundwater recovery plan. Anything less than 4 m has the potential to cause the deaths of trees surrounding the pits. If Kundana would like to move the water levels in the pits closer to 4 m then it will need to be able to demonstrate that water levels in the surrounding area are also under control and at a sufficient depth so as not to cause impact on vegetation.

Licence Holder controls

White Flag Lake – Monitoring

The strategy for managing the risk of dewatering discharge to White Flag Lake is to ensure the licensee undertakes suitable and sufficient monitoring to examine any adverse trends that may occur. Should adverse effects be observed then the licensee will be required to implement a management approach to minimise and avoid this degradation. Enforcement action will be considered by DWER should the licensee fail to take appropriate management measures.

Kundana currently has eight (WF1 to WF8) established sites it uses to monitor the flora (including both macro and micro flora) and fauna (including aquatic and terrestrial invertebrates, aquatic macrophytes and avifauna) of White Flag lake and the fringing environment and sediment chemistry. WF1 to WF3 have been monitored yearly since 2000 while WF4 and WF5 were started in 2001, WF6 in 2003 and WF7 and WF8 in 2004. DER considers this monitoring sufficient to manage the risk of dewatering discharge to White Flag Lake, though the number and frequency of monitoring will be reviewed as a body of information is built.

The licensee shall report this monitoring on an annual basis, as part of the dewatering discharge report. An annual basis is considered appropriate, as it will assist in providing a snap shot of any impact across seasons. Any impact is likely to be gradual and therefore short term reporting is not considered necessary.

Consequence

If dewatering discharge to White Flag Lake occurs, then the Delegated Officer has determined that the impact of the discharge may cause mid-level onsite impacts. Therefore, the Delegated Officer considers the consequence of dewatering discharge to White Flag Lake to be moderate.

Likelihood of Risk Event

The Delegated Officer has determined that the likelihood of occurring is possible at some time. Therefore, the Delegated Officer considers the likelihood of Risk Event 1 to be possible.

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Overall rating of dewatering discharge to White Flag Lake

The Delegated Officer has compared the consequence and likelihood ratings described above with the risk rating matrix (Table 10) and determined that the overall rating for the risk of dewatering discharge to White Flag Lake is medium.

8. Determination of Licence conditions The conditions in the issued Licence in Attachment 1 have been determined in accordance with the Guidance Statement: Setting Conditions.

The Guidance Statement: Licence Duration has been applied and the issued licence expires in two years from date of issue to align with the earliest mining tenement expiry date.

Table 10 provides a summary of the conditions to be applied to this licence.

Table 10: Summary of conditions to be applied

Condition Ref Grounds

General Conditions Condition 1.2

Standard general conditions apply

Premises Operation Condition 1.3

These conditions are valid, risk-based and contain appropriate controls.

Emissions Conditions 2.1 – 2.3

These conditions are valid, risk-based and contain appropriate controls.

Monitoring Conditions 3.1 – 3.4

These conditions are valid, risk-based and consistent with the EP Act.

Information Conditions 4.1 – 4.3

These conditions are valid and are necessary administration and reporting requirements to ensure compliance.

DWER notes that it may review the appropriateness and adequacy of controls at any time and that, following a review, DWER may initiate amendments to the licence under the EP Act.

9. Applicant’s comments The Licence Holder was provided with the draft Decision Report and draft issued Licence on 24 January 2019. The Licence Holder provided comments which are summarised, along with DWER’s response, in Appendix 2.

10. Conclusion This assessment of the risks of activities on the Premises has been undertaken with due consideration of a number of factors, including the documents and policies specified in this Decision Report (summarised in Appendix 1).

Based on this assessment, it has been determined that the Issued Licence will be granted subject to conditions commensurate with the determined controls and necessary for administration and reporting requirements.

Tim Gentle Manager – Resource Industries REGULATORY SERVICES Delegated Officer under section 20 of the Environmental Protection Act 1986

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Appendix 1: Key documents

Document title In text ref Availability

1. Licence L7323/1998/12 – Kundana Gold Mine

L7323/1998/12 DWER records (A1068048)

2. Amendment Notice 1 & 2 L7323/1998/12 – Kundana Gold Mine Licence amended 15 December 2015 & 17 May 2017

Amendment Notice 1 Amendment Notice 2

DWER records (A1344561 and A1433840)

3. Amendment Notice 3 L7323/1998/12, amended 17 November 2017

Amendment Notice 3

DWER records (A1564410)

4. Amendment Notice 4 L7323/1998/12, amended 5 February 2018

Amendment Notice 4

DWER records (A1607364)

5. Application form – replacement of licence_Kundana Gold Pty Ltd – L7323 – 16 January 2019

N/A DWER records (A1756208)

6. DER, July 2015. Guidance Statement: Regulatory principles. Department of Environment Regulation, Perth.

DER 2015a

accessed at www.dwer.wa.gov.au

7. DER, October 2015. Guidance Statement: Setting conditions. Department of Environment Regulation, Perth.

DER 2015b

8. DER, August 2016. Guidance Statement: Licence duration. Department of Environment Regulation, Perth.

DER 2016a

9. DER, November 2016. Guidance Statement: Risk Assessments. Department of Environment Regulation, Perth.

DER 2016b

10. DER, November 2016. Guidance Statement: Decision Making. Department of Environment Regulation, Perth.

DER 2016c

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Appendix 2: Summary of applicant’s comments on risk assessment and draft conditions

Condition Summary of Licence Holder comment DWER response

Section 6.1 in Decision Report:

Delete and replace L16/40 and L16/54 with L16/105 and L16/106

Change accepted – tenements updated

Section 7.4.1 in Decision Report

Edit description of mine dewatering to White Flag Lake to include all current dewatering pits:

Kurrawang

Pope John

Arctic/North

Barkers

Barkers North

Moonbeam

South Pits

Change accepted – all pits have been assessed as approved discharge points during previous amendments. The description has been updated to accurately reflect this.

Condition 1.3.9 Condition 1.3.9 requested the Licence Holder to construct works associated with a new landfill cell in accordance with a specific construction requirement document. The Licence Holder advised this has already been completed and can now be removed.

Change accepted – this has been verified as the compliance certificate was submitted to DWER on 13 March 2017. Condition deleted.

Condition 1.3.10 Condition 1.3.10 refers to table 1.3.6 of Infrastructure Requirements. The Licence Holder has advised that the Barkers Power Station has been decommissioned.

Following further discussion with the Licence Holder, Barkers Power Station will remain on the Licence until such a time they would like to remove it.

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Condition Summary of Licence Holder comment DWER response

Condition 4.2.1 Table 4.2.1 contains incorrect table number references. Table reference numbers corrected.

Condition 4.2.3 Type identified with Table number. Typo corrected.

Conditions 4.3.2 and 4.3.3

The conditions require a compliance certificate to be submitted for the landfill construction as per condition 1.3.9. As discussed above, this has been completed, therefore the conditions are now not applicable.

Change accepted – this has been verified as the compliance certificate was submitted to DWER on 13 March 2017. Condition deleted.

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Attachment 1: Issued Licence L9190/2019/1

Documents

A1757399 L9190 2019 1 Kundana Gold decision report January ... · /lfhqfh / ,5 7 'hflvlrq 5hsruw 7hpsodwh y -xo\ 'hilqlwlrqv ri whupv dqg dfurq\pv ,q wklv 'hflvlrq 5hsruw wkh whupv