Mining Solutions

An effective new leaching aid successfully tested with oxide and mixed sulphide copper ores

ATLASAdvanced Technology for Leaching Aids

Jack BenderMining Solutions, BASF Corporation, USA

Mining Solutions

2

Project Status

Copper Oxide or Secondary Sulfide Ore

Copper Lixiviant (e.g. H2SO4)

Fissures with added contact / Copper extraction

Project Progress All leaching aid fundamental lab work

has been completed SX and Biocompatibility laboratory

work has been completed Customer trials have started Production and Registration complete

Mining Solutions

3

Ore procurement Oxide and Secondary Sulfide Ore classified, analyzed and packaged by expert engineering firm - SGS Sample crushed, screened, split into seven test charges

Unloading Crushed ore Screening

Mining Solutions

4

Agglomeration of Size Fractions

Mining Solutions

5

Leaching Aid Requirements

CRITICAL Aspects Must not affect any downstream processes including Solvent Extraction and

Electrowinning Highly water soluble surfactants that are not extracted into kerosene during SX Cannot stay at the aqueous/organic interface, interfering with kinetics and phase

separation Cannot affect downstream or upstream processes even at very high overdose

concentrations or near critical micelle concentration

Other requirements Must be compatible with native bacteria or inoculated archea Stable at pH << 1 at ambient or slightly elevated temperatures (<50°C) for 3-6 month Needs to Reduce surface tension, but dramatic effect is not recommended Effective at low concentrations: typical dosage range has been 25 ppm

Mining Solutions

6

Phase Disengagement

At extremely high concentrations, 10x dosage, there is an effect on the aqueous continuous phase disengagement, although it is still not a dramatic effect.

Therefore, the leaching aid should only be added directly to the raffinate going to leach

Typical Leaching Aid dose of 25 ppm

Mining Solutions

7

Chemical CompatibilityBatch – Standard QC testing with 10 v/v% LIX 984N

Continuous - 1Ex1Ex1S configuration, 10 v/v% LIX 984N, Mine PLS & Synthetic LE

Obviously no negative effects on SX

Assay Barren Organic E30 E300 S30 S300 Net Transfer Phase Sep (s)Blank Cu 1.42 4.72 4.75 1.64 1.63 3.33 95, 75

%E300 99.37% 99.68%20 ppm Atlas Reagent Cu 1.43 4.69 4.73 1.64 1.63 3.3 85, 80

%E300 99.15% 99.68%50 ppm Atlas Reagent Cu 1.42 4.69 4.72 1.65 1.63 3.3 95, 75

%E300 99.36% 99.35%

Mining Solutions

8

Compatibility with ElectrowinningCopper cathode has been previously plated using a rectifier and simple EW system. The effect of adding a leaching aid was similar to that of a smoothing agent.

This is due to the reduction of the surface tension and the attraction of the polar functional groups of the leaching aid to the high charge density of copper cathode dendrites.

In no cases was there any negative impact from the leaching aid

A

C D

B

Mining Solutions

9

Biocompatibility - Subset of Data – 12Bacteria and Archea Tested

Acidithiobacillus ferrivorans (AFER)iron and sulfur oxidizer (tested on iron)

Acidithiobacillus thiooxidans (ATEX) sulfur oxidizer

Ferroplasma acidiphilum (FACID)archea iron oxidizer

Leptospirillum ferriphilum (LFER)iron oxidizer

Acidophilium acidophilum (AA) heterotroph

Acidithiobacillus ferrooxidans (AFEX)iron oxidizer

* Work performed by Universal Biomining

Mining Solutions

10

Laboratory Column Setup - Oxides Ore agglomerated with water and 25% of the total weight of acid

consumption of the ore 16 columns (2 meter) loaded with 90 Kg each of copper oxide ore after

agglomeration Leach rate - 8 ml/min (0.005 gpm) of 10 g/L sulfuric acid Temperature controlled at ~18ºC Trials conducted as “closed circuits” – copper was extracted from PLS

and the raffinate was dosed with leach aid / necessary acid and recycled back to the columns In some cases PLS treated with solvent extraction with the same results Blanks run with each set of columns

Mining Solutions

11

Laboratory Column Testing – 2M Column Each column leached with dilute

sulfuric acid + leach aid at various concentrations. The control columns leached with acid only Each combination tested in

quadruplicate Daily analysis of PLS includes Cu

content, pH, ORP, free acid and surface tension Standard deviation of column

results was less than 1%

Mining Solutions

12

Trial 5 – Oxide Trial 5

Leaching aid added after agglomeration

Approximately 70% leaching of copper achieved in 30 days

391 g total copper in column at 92% leachable 361 g total

leachable copper

Mining Solutions

13

Trial 6 OxideTrial 6

Leaching aid added during agglomeration

Approximately 70-76% leaching of copper achieved in 60 days

391 g total copper in column at 92% leachable 361 g total

leachable copper

Mining Solutions

14

Trial 7 – Customer Mixed Sulfide

Customer Trial involving the recycle of aqueous

63 g of acid soluble copper (60% leached with LA, 49% leached blank) at 110 days

Initial drop in recovery was expected due to the use of bacterial leaching

Trial 7

Mining Solutions

15

Trial 8 – Oxide – “Chilean Conditions”Trial 8

The oxide ore was leached using leaching aid in all cases

Chloride and nitrate was added in some cases

Only at extremely high concentrations of chloride and nitrate is the leaching suppressed

Mining Solutions

16

Production and Toxicity

Toxicity The leaching aid has been assessed a polymer exemption by the

Toxic Substances Control Act (TSCA) Chemical Substance Inventory and the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). Therefore, it is exempt from the standard toxicity testing required by non-polymer substances

ProductionWe have completed a full scale production run of the leaching aid BASF has sufficient facilities globally to support the mining industry

Mining Solutions

17

Conclusions Leaching Aid has been identified that is compatible with Solvent Extraction,

Electrowinning, and various bacteria/archea

Careful control of column conditions resulted in reproducible results from a four column sample size

Leaching aid concentrations of approximately 25 ppm were optimal while over dosing and under dosing could greatly affect leaching results

The method by which the leaching aid is added to the system can have an influence on the effectiveness of copper leaching

Proceeding with column trials at various customers, a mini-heap trial at one customer and a plant trial at one customer

In the process of providing samples to some customers for testing

Mining Solutions

INTERNAL