Hydrometallurgical Options to Add Valueto Copper Projects and Operations

Peter Rohner

Core Resources, Brisbane

www.coreresources.com.au 24th March 2010

Company Overview

Highlights• Specialist services:

– hrltesting (metallurgical laboratory – operating over 25 years).– Marketing of licensed processing technology (Albion Process).– Process engineering, design and flowsheet development– Scoping and Feasibility Studies– Technology Development Partner

• Strong Technical Team:– Hydrometallurgical expertise– Flowsheet development with an economic focus and outcomes that can

be engineered and operated– Project development and commissioning experience

Copper Leach Flowsheets

In-SituLeaching

Metal RecoverySX/EW

SX/Crystallisation

Precipitation

CementationTailings

ROM ore

Products- Cathode- Sulphate- Cement- Oxide / Sulphide- Other

Dump/HeapLeaching

Concentration(Gravity /Flotation)

ROM ore

ROM ore

Leach Neutralisation

Lower Grade Concentrate

Residue

Acid

AlkalineSize

Fines

By-products- Gold/Silver- Cobalt- Molybdenum- Rhenium- Indium- Uranium- OtherConcentrate

- Lower Impurities (e.g. As,Sb)High GradeConcentrate

ROM ore

In-Situ Leaching• Minerals – Oxides• Lixiviant – Acid or Alkaline• Not widely applied, needs the right geology and permitting• e.g. Mount Gordon - QLD• e.g. Florence, Arizona ex- BHP Copper still on hold

Dump/Heap Leaching• Minerals – Oxides / Sulphides• Lixiviant – Acid or Alkaline (see AmmLeach later)• Widely applied• Pads – Permanent / On-off Pads e.g. Tintaya, Peru (On-off Pad)• e.g. Nifty - WA, Lady Annie - QLD

Copper Leach Flowsheets

Concentrate Leaching• Minerals – Oxides / Sulphides / Refractory Sulphides• Lixiviant – Acid/Alkaline• Processes

- Pressure Oxidation - BIOX- GEOCOAT - CESL- Albion Process - Galvanox- Many others

Copper Leach Flowsheets

AmmLeach• For high carbonate ores and other high acid consuming gangue minerals

(i.e. > 40kg acid/t of ore)• Ammonia used (typically ~3kg ammonia/t of ore)• Similar downstream circuits (SX/EW) and similar capital costs to acid leaching• Pilot Plant run at Leon Copper Project - Argentina in 2007.

Copper Leach Technologies

Pressure Oxidation

Mount Gordon• 1998 – A$93M plant commissioned and ran until 2004, converted to concentrate

production in 2004 as more chalcopyrite ore in feed. Currently on care andmaintenance. 44,000 t/y Cu capacity.

Freeport• 2002 – US$40M Bagdad plant commissioned – converted to Molybdenum

leaching plant in 2009. 15,000 t/y Cu capacity.• 2007 – US$240M Morenci plant commissioned – currently shut down. 70,000 t/y

Cu capacity.

.

Copper Leach Technologies

Pressure Oxidation cont.

CESL• First demonstration plant for Vale in Carajás region of Brazil.• 2009 – US$58M plant commissioned. 10,000 t/y Cu capacity.• Pressure oxidation with chloride

Chelopech• 2011 – US$80M plant with 20,000 t/y Cu capacity.

Activox• Nickel demonstration plant commissioned, but no copper plant.

Copper Leach Technologies

Bacterial Leaching

BIOX / BioCOP• 2004 – US$50M Alliance Copper (BHP Billiton and Codelco) plant

commissioned. 20 000 t/y Cu capacity. The plant was shut down and wasconverted to smelter dust leaching.

GEOCOAT• No copper demonstration plant yet, a pyrite gold plant run in Africa .• Oxidation is typically complete within 45 to 120 days, depending on the

mineralogy.• Need a low carbonate support rock .• Temperature of a GEOCOAT® heap ranges from 25-70oC.• Working capital is significant.

Copper Leach Technologies

Albion Process• No copper demonstration plant yet although unit operations widely used.• Mount Isa Mines dust leach plant gradually to be converted to Albion Plant .• Uses fine grinding and oxidation at ~90oC under atmospheric pressure.• Oxidation is typically complete within 12 to 24 hours, depending on the

mineralogy.

Copper Leach Technologies

Nikko Chloride Process (“N-Chlo Process.”)• US$27M pilot plant being built in Perth now.• 100 t/y Cu capacity• Chloride leaching technology and solvent extraction technology

Galvanox Process• No demonstration plant yet.• Uses pyrite to catalyze reaction.• Atmospheric leach (~80oC).• Pure sulphate medium (no chloride).• No fine grinding.• Fully compatible with conventional SX-EW.

Copper Leach Technologies

Other Processes

HydroCopper - Outotec• Zangezur Copper-Molybdenum Combine CJSC project demonstration plant

operation in 2008-2009 in Finland.• Erdenet Mining Corporation demonstration plant operation at Outotec Research

Center, demonstration of the process technology at Pori, Finland in 2004.• Chloride based technology, using chlorine gas and hydrogen.

Intec• Demonstration plant was constructed and operated during 1998 and 1999 in

Sydney.• Complex chemistry using sodium chloride-sodium bromide electrolyte.• Copper EW from the cuprous (one electron) state.

Copper Leach Technologies

Opportunities to Add Value• Alternative products• By-products• In-situ acid production – reduce acid cost• Use of alternative neutralising materials – reduce neutralising cost• Impurity removal• Integrated flowsheets• Additional metal recovery• Key drivers

Copper Leach Flowsheets

Copper Cathode• Larger scale projects• Low/moderate power costs• Remote / high transport costs

Copper Sulphate• Premium over metal• Smaller scale projects• Power costs higher• Local demand – zinc flotation, fertilizer plant, feedlot

Other (Cement, Copper Sulphide, Copper Oxide)• Copper cement – concentrates or low cost scrap iron available• Intermediate product – market nearby or integrated flowsheet

Copper Leach Product Options

Cu2+ + Fe = Fe2+ + Cu

Smelters don’t pay for many of these elements

Leaching provides an opportunity to recover additionalvalue e.g. Cobalt, Molybdenum, Rhenium, Indium, Uranium

Copper Leach By-product Recovery

Oxide ore / Concentrate

Leach CircuitAir/ Oxygen

Acid

Copper SolventExtraction

Raffinate to Leach

Bleed to by-product recoveryand neutralisation

Advance to EW or Crystallisation

NeutralisationLimestone

Copper Leaching In-situ Acid Production

Oxide ore

Underlying secondaryand primary ore FLOTATION

Leach Circuit

Flotation Tailings

OxygenAcid

HEAP LEACH

SX/EW

Raffinate to Leach

Raffinate to Heap Leach

e.g. Freeport’sMorenci and Bagdad POXplants

Generate excess acid in leaching circuit for oxide leachSeparate pyrite oxidation circuit to generate acid - e.g. Sepon

Recover more pyrite to leachcircuit and oxidise

NeutralisationLimestone

Alternative Neutralising Materials

Oxide ore Concentrate

Leach CircuitOxygen

Acid

HEAP LEACH

SX/EW

Raffinate to Leach

Raffinate to Heap Leach

Turn neutralising stage from cost to a credite.g. Use copper oxide ore (high grade fines) or copper oxide concentrate instead

of limestone / lime.

Neutralisation

FinesCoarse

Impurity Removal

Many large undeveloped copper deposits havesignificant impurity issues.• Salobo, Brazil High Fluorine

• La Granja, Peru High Arsenic

• Tampakan, Philippines High Arsenic

• Nena, PNG High Arsenic

• Many other South AmericanCopper Projects High Arsenic

Core continues to be active further developing alkalineleaching technology to remove arsenic and antimonyfrom copper concentrates.

Copper Leaching / Smelter Synergies

Low Grade Concentrate Arsenic Rich Smelter Dust

Neutralisation

Copper Solution to Copper Recovery

LimestoneAir

Ferric ArsenateGypsum Residue

Leach CircuitOxygen

SmelterAcid

SolidLiquid

“IronSource”

Concentrate and Leaching Synergies

Case Study

Normal grade concentrate for sale

vs.

High grade concentrate for sale

plus

Low grade concentrate to leaching

Copper Recovery

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Co

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Copper Grade/Recovery

+ + + + ++

PerfectSeparation

Target ConcentrateGrade - 25% Cu

Liberated Chalcopyrite

Max. TheoreticalRecovery

Copper Recovery

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PerfectSeparationPlant Separation

Target ConcentrateGrade - 25% Cu

+

Liberated Chalcopyrite

Liberated Gangue recovered by "Entrainment" or "True" Flotation

Plant Recovery

Copper Recovery – Case Study

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Co

pp

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Copper Recovery %

Copper Grade/Recovery

+ + + + ++

Target ConcentrateGrade - 30% Cu

Liberated Chalcopyrite

30% Recovery toLower Grade Copper

Concentrate - 7.5% Cu

Concentrate forSale

Concentrate forLeaching

Case Study

Base Case• 1,500,000 tonnes per year of ore @ 2% Copper.• Conventional concentrate production – 80% Copper recovery• Sell concentrate – 96,000 tonnes @ 25% Copper grade

(24,000 tonnes of Copper contained)

Assumed Copper Price US$3.00 /lbTC US$50 /tRC US 5c /lb

Case Study

Alternative Hydromet. Case• 1,500,000 tonnes per year of ore @ 2% Copper.• High grade concentrate production – 60% Copper recovery• Sell high grade concentrate – 60,000 tonnes @ 30% Copper grade

(18,000 tonnes of Copper contained)

• Recover low grade concentrate and treat hydrometallurgically• Low grade concentrate – 120,000 tonnes at @ 7.5% Copper grade

( 9,000 tonnes of Copper contained)• Leach low grade concentrate – 90% Copper recovery to Copper Sulphate

product (8,100 tonnes of Copper contained)

• Total payable copper – 26,100 tonnes (vs. 24,000 for base case)

Case Study

Positives• Additional 2,100 tonnes of copper recovered• Higher revenue per tonne of copper (copper sulphate premium, higher payable

lower deduct)• Lower freight and treatment charges• Additional ~$30M in net revenue (from above)• Additional by-product revenue ?

Negatives• Additional leach circuit and product to handle / sell• Additional capital cost ~$50M, Additional leach circuit costs ~$10M

Conclusion• Robust project

Key drivers that provide opportunities

• Can only produce “dirty” unsaleable concentrates• Concentrate transport costs high - far from markets• Low power costs• Limestone/other neutralising material available and low cost• Acid available and low cost (or low power cost)• Existing infrastructure available (old oxide leaching operation SX/EW plant)• Local demand for copper sulphate or intermediate• Potential for by-products credits• Significant recovery improvements

Summary

Questions ?