Teck – Aurubis: An integrated mine to metal approach to develop high arsenic copper deposits using the CESL process

8/9/2019 Teck – Aurubis: An integrated mine to metal approach to develop high arsenic copper deposits using the CESL process

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Introduction

Strong demand for copper from emerging economies will place increasingpressure on developing new mine capacity

Future capacity will increasingly have to be mined from non-traditionalcopper resources, specifically those with lower grades, more complexmineralogy, and increasing levels of deleterious elements

One element that has garnered considerable industry attention is arsenic,where concentrations in existing and future mines appear to be on the rise

Arsenic is among the most challenging elements for copper smelters tocontrol as it contributes to environmental concerns during metallurgicalprocessing and materials management

Photo: Antamina Operation, Peru


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The Arsenic Challenge

Lack of arsenic processing capacity from2015 onwards: 30 kt to 40 kt of arsenic

0.16%

0.22% 0.22%

Increasing arsenic levels in concentrates and increasingly restrictiveenvironmental legislation worldwide is widening the gap between capacityto handle arsenic in smelters and arsenic in concentrates

71 78 172 19481 87 142 165

2008 2010 2015 2020

X :Arsenic in concentrates [kt]

X :Arsenic smelting capacities [kt]

Assumption: Maximum global average

arsenic in concentrate blend: 0.21% As

71 78 172 194

2008 2010 2015 2020

.

X :Arsenic in concentrates [kt]

:Global average arsenicconcentration

X

Source: Internal analysis, data from Brook Hunt


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Teck – AurubisTechnical Partnership (1 of 2)

Teck and Aurubis independently identified increasing arsenic content incopper ores and copper concentrates as an emerging challenge, andpotential opportunity, for the copper industry

Teck has developed a proprietary hydrometallurgical process (CESL) to

treat copper concentrates, including those with elevated arsenic

Aurubis is the leading processor of complex custom concentrates by usingenvironmentally sound state of the art technologies

sustainable mine to metal solution to exploit future copper resources highin arsenic concentration

Photos: Copper production, Aurubis operations, Germany


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Teck – AurubisTechnical Partnership (2 of 2)

Strategic joint investment to solve technical issues related to treatingconcentrates with elevated arsenic using hydrometallurgy

Strong technical, environmental, safety, and product stewardship alignmentbetween companies

Provides an environmentally sound and cost effective on-site processingroute for high arsenic bearing copper and copper-gold ore bodies

Copper-Arsenic

Exploration

Mining

Milling

Concentrate

Smelting

Refining

Cu Products

Recycling

Mining

Milling

CESL Refinery

Cathode

Processing Route


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Teck-Aurubis’ approach to processing high arsenic bearing concentrates isfavorable as mineral extraction and arsenic fixation takes place in a singleautoclave vessel

The technology effectively treats refractory copper sulphide mineralswithout the use of exotic reagents, ultra-fine grinding, or extremetemperature and pressure

Importantly CESL technology uses existing commercial technologies suchas ressure oxidation solvent extraction and electrowinnin

CESL Copper-Arsenic Technology

It has been thoroughly developed and proven at scale achieving highmetallurgical recoveries and product quality requirements

Photos: Vale’s 10ktpa copper cathode CESL refinery, Brazil


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CESL Copper Process

Copper minerals are oxidized and leachedusing recycled raffinate

− Arsenic minerals: predominantlyenargite (Cu3AsS4) and tennantite

(Cu12As4S13)

Autoclave conditions: 150°C, 1380 kPa,60-90 minutes retention time

Copper Concentrate

Pressure oxidation

Cu leach residuewashin

on ons promo e arsen c o reac wiron and precipitate as ferric arsenate

Cu leach residue is washed and filtered

Partial neutralization of raffinate for acidbalance control

Leach liquor is processed through solventextraction

Copper is transferred to pure electrolyte

stream and cathodes plated

Solvent extraction

Electrowinning


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CESL Gold Process

Gold and silver are leached at elevatedpressure with recycled cyanide solution

Limited dissolution of sulphur because ofshort leach retention time

Gold and silver recovery using standardcarbon Adsorption-Desorption (ADR) andelectrowinning technology

Cu leach residue

Pressure cyanide

leach

Precious metalsrecovery

opper recovery rom so u on ancyanide regeneration from recycledsolution (Acidification)

Cyanide recovery from plant effluentstream (Volatilization – Reneutralization)

Cyanide destruction by conventionalmeans on minor bleed stream

Cyanide recovery

Cyanide Destruction


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Technical Program

A comprehensive 24-month technical work program started in Q3 2009 toassess the application of CESL technology to high arsenic bearing copperand copper-gold concentrates

The program included a series of bench, continuous pilot, and

demonstration scale testing to achieve the following main objectives:

− Determine level of occupational exposure to arsenic during pilotoperations

−

− Assess arsenic deportment in the copper and gold processes andgenerate representative final residue samples for stability analysis

− Develop protocol and complete residue stability program with Dr.George Demopoulos (Professor, McGill University, Montreal, Canada)

− Confirm engineering design criteria, materials of construction and de-risk the scale-up of the gold process by operating a demonstration plant


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Technical ResultsSummary (1 of 3)

Copper and Gold Plant Leaching Results

High copper extractions (~97% - 98%) were achieved at bench and pilotfrom a wide range of arsenic bearing concentrates (~1.4% - 4.6% arsenic)

Near quantitative deportment of arsenic to Cu leach residue (>99%);minor levels of arsenic leached into circulating process solution (


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Health and Safety

Sample data confirmed air quality (


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Gold Demonstration Operations

Project exceeded ramp up targets to design rates in first few months

To date has achieved exceptional metallurgical performance:

− 90% - 95% gold extraction and 85% silver extraction from gold plant

− >98% gold recovery and >95% silver recovery from leach liquor

− 93% c anide recover from AVR lant

−


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Case Study (1 of 3)

Collectively Teck and Aurubis have completed multiple preliminary financialevaluations to assess the commercial viability of a mine to metal operationfor high arsenic resources using CESL technology

The economic assessment presented in this paper incorporates

metallurgical results from a series of high arsenic bearing copperconcentrate samples, two from Northern Peru projects

Mine-mill1, and refinery2 cost estimates were gathered from externalconsultin and service rou s and ast CESL feasibilit studies

Project Assumptions - Mine, Mill, CESL Refinery

~200k t/a copper cathode

~65k oz/a gold~1.3M oz/a silver

~3,500 US$M ~1.10 US$/lb Cu

Equivalent3

1 - Brook Hunt Copper Mine Cost Service (March 2011): Greenfield Projects Capital Intensity2 - Internal estimate: Factored from third party engineering cost estimates for CESL Cu-Au refinery3 - Brook Hunt metal prices (March 2011): 2.50 US$/lb Cu, 900 US$/oz Au, 15 US$/oz Ag


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Case Study (2 of 3)

The positive results of the case study show that developing an integratedmine to metal project on an arsenic containing copper-gold deposit can beeconomically feasible with today’s long-term metal price assumptions

With a break-even copper price of ~2.00 US$/lb, the economics of a

project of this scale are robust enough to show a noteworthy positivereturn given the current market forecasts

NPV Sensitivities

Cu Price CAPEX OPEXconom c a ua on – re ax

Financial Metric Project

NPV4 ~1,700 US$M

IRR ~14%

Break-Even Price ~2.00 US$/lb

4 - 8% Discount Rate-$1,000

-$500

$0$500

$1,000

$1,500

$2,000

$2,500

$3,000

$3,500$4,000

-30% 0% +30%

N P V

( $ M i l l i o n s )

Change in Cost and Price


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Case Study (3 of 3)

As industry best practices were assumed for the mine-mill component ofthe case study, the following aspects related to the hydrometallurgicalrefinery are discussed:

− Residue Management: safe storage of stable form of ferric arsenate

bearing residue in a lined pond with long term monitoring is possible

− Air Quality: lower direct impact on air quality from hydrometallurgicalrefinery; impact from indirect emissions comparable to industry standards

− a er se m ss ons: ne wa er eman or process compares we o

traditional copper market standards; use of seawater is possible

− Health & Safety: occupational exposure to arsenic is expected to be lowand manageable based on recent pilot trials of high arsenic bearingconcentrates

− Community Social Responsibilities and Potentials: positive proactiveengagement is critical; in country value added production of coppercathode has the potential to yield significant additional benefits to thecommunity


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Conclusions

The implementation of CESL technology through an integrated mine-to-metal approach is a sustainable option for the processing of ore fromarsenic challenged copper resources

The technical program undertaken by the Teck-Aurubis partnership has

confirmed: metallurgical performance objectives, sound environmental,health and safety performance standards, and commercial assumptionsand project economics

This success is allowing Teck and Aurubis to pursue copper resources not

previously considered for development using an economically competitiveand environmentally superior process

Photos: Teck South American operations

Documents

Teck – Aurubis: An integrated mine to metal approach to develop high arsenic copper deposits using the CESL process