DRAFT ACID MINE DRAINAGE POTENTIAL ASSESSMENT: VOLSPRUIT WASTE ROCK AND TAILINGS SAMPLES

Transcription

1 DRAFT ACID MINE DRAINAGE POTENTIAL ASSESSMENT: VOLSPRUIT WASTE ROCK AND TAILINGS SAMPLES ESCIENCE ASSOCIATES (PTY) LTD POSTAL ADDRESS: PO Box 2950 Saxonwold 2132 PHYSICAL ADDRESS: 9 Victoria Street Oaklands Johannesburg 2192 TEL: FAX: WEBSITE: info@escience.co.za R No 2009/014472/07 September 2012

2 DRAFT ACID MINE DRAINAGE POTENTIAL ASSESSMENT: VOLSPRUIT WASTE ROCK AND TAILINGS SAMPLES COMPILED BY: EScience Associates (Pty) Ltd. PO Box 2950, Saxonwold, Victoria Street, Oaklands, Johannesburg, 2192 Tel: (011) Cell: Fax: info@escience.co.za ON BEHALF OF APPLICANT: Pan Palladium South Africa (Pty) Ltd., a subsidiary company of Sylvania Platinum Limited Constantia View Estate, Block 3 2 Hogsback Road Roodepoort, 1709 SOUTH AFRICA Tel: (011) Fax September 2012 Escience Associates (Pty) Ltd Page i

3 1. EXECUTIVE SUMMARY EScience Associates (Pty) Ltd. (hereinafter referred to as ESA ) were commissioned by the Proponent (hereinafter referred to as Sylvania ) to undertake an assessment/quantification of the degree to which the mine residue wastes from the proposed Volspruit Opencast Platinum Group Metal (PGM) Mine are likely to result in the generation of acid mine drainage (AMD). The materials analysed toward meeting the above objective are deemed representative of inter alia the following: Mine tailings derived from the processing of target ore at the proposed processing plant; and Waste rock resultant from efforts to get to the target ore body through opencast mining operations (and by implication also representative of hanging walls on the respective pits) A total of 19 samples were used to undertake the assessment. The samples were selected from existing exploration cores to be representative of waste rock from the proposed operations, as well as the targeted ore body itself. The ore body samples were processed in a pilot plant replica of the proposed Volspruit processing plant technology. This was done to produce a single, composite, tailings sample that is deemed representative of that to be produced by the operational mine. The waste rock samples and the single tailings sample were analysed through numerous methods to give a combined estimation of their acid formation capabilities, as follows: Paste ph; Sulphur and carbon concentrations using LECO (ABA_LECO); Neutralising potential (NP) AS4969; and Net acid generation (NAG) 1997/AS216. All the samples ultimately showed i) high neutralization potential over acid potential ratios, ii) above neutral paste ph and iii) below (or equal to 0 in one case) NAPP values. All of these results indicated that the waste rock and tailings samples have very little net acid formation potential. Escience Associates (Pty) Ltd Page ii

4 TABLE OF CONTENTS 1. EXECUTIVE SUMMARY... II 2. INTRODUCTION AND BACKGROUND PROPOSED ACTIVITY ACID MINE DRAINAGE ACID BASE ACCOUNTING SCOPE GEOCHEMICAL ANALYSIS PASTE PH LECO SULPHUR AND CARBON CONCENTRATIONS NET ACID FORMATION POTENTIAL ADDITIONAL TESTS PERFORMED ON THE SOUTH PIT CONCLUSIONS REFERENCES... 9 APPENDIX 1 RAW DATA Escience Associates (Pty) Ltd Page iii

5 List of Figures Figure 2-1: Location of site... 1 Figure 2-2: Sampling locations (only those in the coloured areas representing different parts of the ore body were processed. These were composited as in Table List of Tables Table 2-1: The locations and names of the various waste rock samples... 3 Table 3-1: Paste ph results for the various samples including the solids to liquid volume ratios... 5 Table 3-2: Measured sulphur, -SO4, Carbon and -CO3 contents... 6 Table 3-3: The ratio of neutralisation potential versus acid formation potential... 6 Table 3-4: Acid forming categorisation (Miller et al., 1997))... 7 Table 3-5: The potential of the materials to generate acid in terms of Table 3-4 (NAPP rating calculation according to (Miller and Jeffery, 1995)... 7 Table 3-6: Analysis obtained from the south pit... 8 Table 3-7: Criteria used for the additional south pit analysis... 8 Table A - 1: Acid base accounting tests for samples WR1 to WR Table A - 2: Acid base accounting tests for samples WR9 to WR 15 and the tailings sample Table A - 3: Chemical analysis for samples WR1 to WR 8 and the tailings sample Table A - 4: Chemical analysis for samples WR1 to WR 8 and the tailings sample Table A - 5: Leaching results of samples WR1 to WR Table A - 6: Leaching results of samples WR1 to WR Escience Associates (Pty) Ltd Page iv

6 List of Abbreviations ABA AP ARD AMD ANC ANP MPA NAF NAG NAPP NP Acid base accounting Acid producing potential Acid rock drainage Acid mine drainage (a form of ARD) Acid neutralization capacity Acid neutralization potential Maximum potential acidity Non-acid forming Net acid generation Net acid producing potential Neutralization potential Escience Associates (Pty) Ltd Page v

7 2. INTRODUCTION AND BACKGROUND Sylvania propose to establish an opencast platinum group metal (PGM) mine and associated supporting infrastructure on the farms Volspruit 326 KP and Zoetveld 294 KR near Mokopane in the Limpopo Province. Sylvania has appointed ESA, as independent environmental assessment practitioners, to undertake the necessary environmental impact assessment (EIA) and requisite environmental application processes on their behalf. As part of the EIA being undertaken, the acid formation potential of the mine waste rock and tailings was analysed by ESA to determine the propensity for the proposed mine to result in the generation of acid mine drainage (AMD). The proposed mine would be situated on the farms Volspruit 326 KP and Zoetveld 294 KR (Figure 2-1). Figure 2-1: Location of site 2.1 PROPOSED ACTIVITY Sylvania proposes the mining of two (2) separate ore bodies through open cast mining on the farm Volspruit 326 KP, Mokopane, Limpopo Province. In addition, following consultation with the surface right owners, areas of the Farm Zoetveld 294 KR are considered for the establishment of supporting above ground infrastructure. Escience Associates (Pty) Ltd Page 1

8 The mining of these two (2) ore bodies will result in two separate open cast pits being established, the so-called North Pit and the South Pit. It is estimated that the ore reserves underlying the site equal approximately 28 million tonnes, which suggests that the mine will be in operation for approximately years. It is proposed that Platinum Group Metals (PGM s) will be mined to a depth of approximately 180m at the North Pit and 180m at the South Pit. The site is currently a Green-fields site under intense agriculture and as such all relevant surface infrastructure and other infrastructural requirements for the project will need to be developed. The development is expected to include access roads, administration buildings, workshops, storage/ lay-down yards, sewage treatment plants, open cast pits, processing plant, conveyors, slimes dam, return dams, electricity substations, electricity generation plant(s), a smelter complex, Chemical Vapour Metal Refining (CVMR) plant, as well as supporting electrical and reticulations. 2.2 ACID MINE DRAINAGE Acid mine drainage is a specific term given to a collection of occurrences called acid rock drainage, whereby a rock body can produce acids after oxidisation. A typical example of this is the exposure of pyrite to air followed by its exposure to. This produces sulphuric acid (H2SO4) which can drain into underground (and above ground in certain cases) bodies with potentially devastating effects on the local environment, depending on the amount of acid generated. 2.3 ACID BASE ACCOUNTING Some samples have the potential to both produce acids, as well as then neutralise them. For example, a sample containing both pyrites (FeS2) and carbonates (CO3 2- ) will produce acids through pyrite oxidation, which may subsequently get neutralised by the CaO. Acid Base Accounting (ABA) is an analysis that takes the neutralisation potential of alkaline, or basic, substances into account when considering the acid generation potential of a sample. There are various types of test methods used to undertake ABA, with most of these assuming a maximum amount of acid generation through the conversion of all available sulphur in the sample into acid. To determine the neutralisation potential, titration (i.e. measured neutralisation) is used to either increase or decrease the ph of the sample to a predetermined ph level. The amount of acid/base, depending on whether the titration ph is higher or lower than the sample s natural ph, needed for the titration will indicate how much neutralisation potential the sample has. The amount of acid consumed during the titration is the neutralisation potential of the sample that can be compared with the calculated maximum acid that can be generated to indicate if the sample can neutralise the acid itself might produce, or if it will have a net acid generation potential (i.e. when the acid potential exceeds the neutralisation potential). Escience Associates (Pty) Ltd Page 2

9 2.4 SCOPE A total of 15 samples were taken at various depths and locations across the proposed north pit area to give a representative set of samples for the planned excavation (Figure 2-2). The samples were then separated into ore (i.e. underlying material containing targeted PGM mineral deposit) and waste rock (i.e. non-pgm mineral containing material that needs to be mined to gain access to the ore body) and composites were made for general areas of the waste rock (Table 2-1). The ore samples were lumped together and processed in an identical way to which the actual planned process will be processing the ore. The tailings from this mock processing was analysed along with the individual waste rock samples for their potential to form AMD while taking into account their propensity to neutralise acids. Table 2-1: The locations and names of the various waste rock samples Sample Number Depth Range (m) Comp. from bore holes Area No From To Position Comments N0901 (WR1) 0 47 South 1 Hanging-wall N0902 (WR2) South 2 Hanging-wall N0903 (WR3) South 3 Hanging-wall N0904 (WR4) South 4 Hanging-wall Immediately above reef N0905 (WR5) South 5 Foot-wall Immediately below reef N0906 (WR6) 0 40 North 1 Hanging-wall N0907 (WR7) North 2 Hanging-wall N0908 (WR8) North 3 Hanging-wall N0909 (WR9) North 4 Hanging-wall Immediately above reef N0910 (WR10) North 5 Foot-wall Immediately below reef N0911 (WR11) N to S 2 Hanging-wall N0912 (WR12) N to S 3 Hanging-wall N0913 (WR13) N to S 4 Hanging-wall Immediately above reef N0914 (WR14) N to S 5 Foot-wall Immediately below reef N0915 (WR15) N to S 6 Foot-wall Escience Associates (Pty) Ltd Page 3

10 Figure 2-2: Sampling locations (only those in the coloured areas representing different parts of the ore body were processed. These were composited as in Table 2-1. Escience Associates (Pty) Ltd Page 4

11 3. GEOCHEMICAL ANALYSIS The samples were analysed using the following tests: Paste ph; Sulphur and carbon concentrations using LECO (ABA_LECO); Neutralising potential (NP) AS4969; and Net acid generation (NAG) 1997/AS PASTE PH Paste ph is used to provide a relative measure of a samples ability to produce AMD. Simplistically speaking, the higher the sample s paste ph, the more basic it is, and the more likely it therefore is to neutralise any acids that may form through oxidation. If the paste ph of a sample is low, it is deemed acidic with a high potential for AMD formation. In the case of the samples taken for this assessment, all had a basic paste ph (including that of the tailings material) (Table 3-1). This gives an initial indication that the waste rock and tailings from the mine will have little or no overall acid forming potential. Table 3-1: Paste ph results for the various samples including the solids to liquid volume ratios Sample WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 Paste ph g solids/ml Water Sample WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailings Paste ph g solids/ml Water LECO SULPHUR AND CARBON CONCENTRATIONS LECO is a combustion analysis method used to measure the carbon and sulphur content of a sample, as these elements are not easily detected using typical induction coupled plasma (ICP) spectroscopy. The sulphur and carbon content of a sample is needed in the ABA assessment, as it gives an indication of the potential amount of sulphuric acid (H2SO4) that can be formed from the sample, as well as the acid neutralization potential provided from calcium carbonates (CaCO3) in the sample, respectively. The majority of the samples analysed for this assessment had a sulphur and carbon content below 0.1 and 1%, respectively. Samples from the northern section of the pit (Figure 2-2), however, had higher carbon contents (up to 3.9%), which would further support the acid neutralisation potential thereof. On average the waste rock showed a higher potential for acid neutralization than production. The same was observed for the composite tailings sample (Table 3-2). Escience Associates (Pty) Ltd Page 5

12 Table 3-2: Measured sulphur, -SO4, Carbon and -CO3 contents Sample WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 Sulphide as S % Sulphate as SO4 % Total carbon as C % Carbonate as CO3 % Sample WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailings Sulphide as S % Sulphate as SO4 % Total carbon as C % Carbonate as CO3 % NET ACID FORMATION POTENTIAL To determine the net acid formation potential (NAFP) for a sample, the total potential acid that can be formed from the sample is compared to the total neutralisation potential thereof to give a ratio of the neutralising potential (NP) over acid producing potential (AP). Both NP and AP are expressed in terms of CaCO3 equivalents. The higher this ratio the more likely it is that the waste rock and tailings will neutralise acids potentially formed in the rock/tailings. The measured sample ratios confirmed the paste ph results, in that the samples are unlikely to produce AMD, but instead might neutralise acids. The samples tested all had a very high NP/AP ratio (Table 3-3), indicating the samples have a much higher potential for neutralizing acids than they do for producing them. Table 3-3: The ratio of neutralisation potential versus acid formation potential Sample WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 Acid potential (AP) kg CaCO3/T Neutralising potential (NP) kg CaCO3/T NP/AP Ratio Sample WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailings Acid potential (AP) kg CaCO3/T Neutralising potential (NP) kg CaCO3/T NP/AP Ratio Another method used in ABA deduces the acid neutralization capacity (ANC) of the sample from its NP, and the maximum potential acidity (MPA) from its Sulphide content. By then subtracting the ANC from the MPA it is possible to determine the net acid generating potential (NAPP) of a sample. Escience Associates (Pty) Ltd Page 6

13 The NAPP of the sample is then considered in conjunction with the net acid generation (NAG) ph to categorise the sample in respect if its acid forming potential (Table 3-4). The samples assessed for this study all fell in the non-acid forming category (Table 3-5). Table 3-4: Acid forming categorisation (Miller et al., 1997)) Category NAPP NAG ph Potentially acid forming (PAF) >0 <4.5 Non acid forming (NAF) <0 4.5 Inconclusive > <4.5 Table 3-5: The potential of the materials to generate acid in terms of Table 3-4 (NAPP rating calculation according to (Miller and Jeffery, 1995) Sample WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 ANC = NP (i.t.o CaCO3/t) *0.98 Sulphide as S MPA = 30.6 x S% NAG ph NAPP = MPA - ANC Classification NAF NAF NAF NAF NAF NAF NAF NAF Sample WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailings ANC = ANP (i.t.o CaCO3/t) *0.98 Sulphide as S MPA = 30.6 x S% NAG ph NAPP = MPA - ANC Classification NAF NAF NAF NAF NAF NAF NAF NAF Net acid generation (NAG) is an indication of the total amount of H2SO4 that will be formed by the material when exposed to. The amount of acid is determined by titration, measuring the amount of acid needed to bring the sample down/up to ph levels of 4.5 and 7. The tests performed had a lower detection limit of 0.5 kg H2SO4, which was the consistently measured value for all samples, including the tailings. This suggested that there was virtually no net acid produced by the samples. Instead, the higher initial ph levels confirmed the other test results, which suggested that the material will serve as a deterrent to acid mine drainage generation. 3.4 ADDITIONAL TESTS PERFORMED ON THE SOUTH PIT Further to the North pit trials, additional analyses were performed on samples obtained from the south pit. These showed similar results, resulting in all the samples also being classified as non-acid forming (Table 3-6, Table 3-7). The south pit analyses were undertaken by GeoPollution technologies as part of their geo-hydrological impact assessment for the EIA, and used to supplement this report. The results obtained are commensurate with, and expected, in the context of the similar mineralogy of the north and south pits. Escience Associates (Pty) Ltd Page 7

14 Table 3-6: Analysis obtained from the south pit Acid Base Accounting Modified Sobek (EPA-600) Sample Identification Composite 1 Composite 2 Composite 3 Composite 4 Composite 4 Sample Number D Paste ph Total Sulphur (%) (LECO) < Acid Potential (AP) (kg/t) Neutralization Potential (NP) Nett Neutralization Potential (NNP) Neutralizing Potential Ratio (NP : AP) Rock Type III III III III III Table 3-7: Criteria used for the additional south pit analysis Categorization Outcome Criteria TYPE I Potentially Acid Forming Total S(%) > 0.25% and NP:AP ratio 1:1 or less TYPE II Intermediate Total S(%) > 0.25% and NP:AP ratio 1:3 or less TYPE III Non-Acid Forming Total S(%) < 0.25% and NP:AP ratio 1:3 or greater 4. CONCLUSIONS From the ABA undertaken for the assessment, it is evident that both the waste rock and the tailings samples have little potential for AMD formation, but instead have the tendency to neutralise AMD generation. The Volspruit mine residues themselves are, therefore, expected to have no risk of acid mine drainage formation due to the results obtained through the representative sampling and analyses undertaken for this assessment. Escience Associates (Pty) Ltd Page 8

15 5. REFERENCES Miller, S, Robertson, A, and Donohue, T (1997) Advances in Acid Drainage Prediction Using the Net Acid Generation (NAG) Test, Proceedings of the 4th International Conference on Acid Rock Drainage, Vancouver, May 31-June 6, 1997 Miller, S and Jeffery, J (1995) Advances in the Prediction of Acid Generating Mine Waste Materials, Proceedings of the Second Australian Acid Mine Drainage Workshop, Charters Towers, Queensland, March 1995 Escience Associates (Pty) Ltd Page 9

16 APPENDIX 1 RAW DATA Table A - 1: Acid base accounting tests for samples WR1 to WR 8 Analyte Name Units Reporting Limit WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 Paste ph No unit Fizz Rating Sample Weight g Normality of standardised HCl N Volume of HCl added ml Normality of standardised NaOH N Titre of NaOH ml NP as kg CaCO3/T kg CaCO3/T Total sulphur as S % <0.01 Sulphide as S % < <0.01 Sulphate as SO4 % 0.03 < < <0.03 Total carbon as C % Carbonate as CO3 % Acid potential kg CaCO3/T < <0.31 Net neutralising potential kg CaCO3/T NP AP ratio Classification - 0 PAN PAN PAN PAN PAN PAN PAN PAN NAG ph NAG as kg H2SO4/tonne at ph 4.5 kg H2SO4/T 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 NAG as kg H2SO4/tonne at ph 7.0 kg H2SO4/T 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 Escience Associates (Pty) Ltd Page 10

17 Table A - 2: Acid base accounting tests for samples WR9 to WR 15 and the tailings sample Analyte Name Units Reporting Limit WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailing Paste ph No unit Fizz Rating Sample Weight g Normality of standardised HCl N Volume of HCl added ml Normality of standardised NaOH N Titre of NaOH ml NP as kg CaCO3/T kg CaCO3/T Total sulphur as S % Sulphide as S % <0.01 < <0.01 < Sulphate as SO4 % Total carbon as C % Carbonate as CO3 % Acid potential kg CaCO3/T <0.31 < <0.31 < Net neutralising potential kg CaCO3/T NP AP ratio Classification - 0 PAN PAN PAN PAN PAN PAN PAN PAN NAG ph NAG as kg H2SO4/tonne at ph 4.5 kg H2SO4/T 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 NAG as kg H2SO4/tonne at ph 7.0 kg H2SO4/T 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 < Escience Associates (Pty) Ltd Page 11

18 Table A - 3: Chemical analysis for samples WR1 to WR 8 and the tailings sample Analyte Name Units Reporting Limit WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 Aluminium oxide (XRF) % Calcium oxide (XRF) % Chromium oxide (XRF) % Iron oxide (XRF) % Potassium oxide (XRF) % Magnesium oxide (XRF) % Manganese oxide (XRF) % Sodium oxide (XRF) % Phosphorous oxide (XRF) % Silicon oxide (XRF) % Titanium oxide (XRF) % Vanadium oxide (XRF) % 0.01 <0.01 <0.01 <0.01 < <0.01 <0.01 <0.01 Loss on ignition (XRF) % Antimony ppm 2 <2 <2 <2 <2 <2 <2 <2 <2 Arsenic ppm <2 Barium ppm Beryllium ppm 0.5 <0.5 <0.5 <0.5 <0.5 < Bismuth ppm < <0.5 <0.5 <0.5 <0.5 Cadmium ppm 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 Cobalt ppm Copper ppm Lead ppm Lithium ppm Mercury ppm 3 <3 <3 <3 <3 <3 <3 <3 <3 Molybdenum ppm Nickel ppm Silver ppm 2 <2 <2 <2 <2 <2 <2 <2 <2 Escience Associates (Pty) Ltd Page 12

19 Table A - 3: Chemical analysis for samples WR1 to WR 8 and the tailings sample Analyte Name Units Reporting Limit WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 Selenium ppm 5 <2 <2 <2 <2 <2 <2 <2 <2 Strontium ppm Tin ppm Zinc ppm Zirconium ppm Table A - 4: Chemical analysis for samples WR1 to WR 8 and the tailings sample Analyte Name Units Reporting Limit WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailing Aluminium oxide (XRF) % Calcium oxide (XRF) % Chromium oxide (XRF) % Iron oxide (XRF) % Potassium oxide (XRF) % Magnesium oxide (XRF) % Manganese oxide (XRF) % Sodium oxide (XRF) % Phosphorous oxide (XRF) % Silicon oxide (XRF) % Titanium oxide (XRF) % Vanadium oxide (XRF) % <0.01 <0.01 <0.01 <0.01 <0.01 < Loss on ignition (XRF) % Antimony ppm 2 <2 <2 <2 <2 <2 <2 <2 <2 Arsenic ppm 1 < <2 <2 <2 5. Barium ppm Beryllium ppm < <0.5 <0.5 1 <0.5 <0.5 Bismuth ppm 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 Cadmium ppm 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 Cobalt ppm Copper ppm Escience Associates (Pty) Ltd Page 13

20 Table A - 4: Chemical analysis for samples WR1 to WR 8 and the tailings sample Analyte Name Units Reporting Limit WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailing Lead ppm Lithium ppm Mercury ppm 3 <3 <3 <3 <3 <3 <3 <3 <3 Molybdenum ppm Nickel ppm Silver ppm 2 <2 <2 <2 <2 <2 <2 <2 <2 Selenium ppm 5 <2 <2 <2 <2 <2 <2 <2 <2 Strontium ppm Tin ppm <0.5 Zinc ppm Zirconium ppm Oxides reported as: Al2O3, CaO, Cr2O3, Fe2O3, K2O, MgO, MnO, Na2O, P2O5, SiO2, TiO2 and V2O5 Table A - 5: Leaching results of samples WR1 to WR8 Analyte Name Units Reporting Limit WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 Extraction Fluid 0 Final ph Silver mg/l <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 Arsenic mg/l <0.003 <0.003 <0.003 <0.003 <0.003 <0.003 <0.003 Boron mg/l <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 Barium mg/l Beryllium mg/l <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 Bismuth mg/l <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Cadmium mg/l <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 Cobalt mg/l <0.002 <0.002 < Chromium mg/l < Copper mg/l <0.004 <0.004 < Escience Associates (Pty) Ltd Page 14

21 Table A - 5: Leaching results of samples WR1 to WR8 Analyte Name Units Reporting Limit WR1 WR2 WR3 WR4 WR5 WR6 WR7 WR8 Mercury mg/l < < < < < < Lithium mg/l 0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 Manganese mg/l < Molybdenum mg/l <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 Nickel mg/l <0.007 <0.007 < < Lead mg/l <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 Antimony mg/l <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 Selenium mg/l <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 Tin mg/l <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 Strontium mg/l Vanadium mg/l <0.003 Zinc mg/l <0.015 <0.015 <0.015 <0.015 < <0.015 <0.015 Zirconium mg/l <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 Aluminium mg/l <0.02 <0.02 < Calcium mg/l Iron mg/l 0.05 <0.05 <0.05 <0.05 <0.05 < <0.05 <0.05 Potassium mg/l Magnesium mg/l Sodium mg/l < Silicon mg/l Titanium mg/l <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 Hexavalent Chromium mg/l 0.01 <0.01 <0.01 <0.01 < <0.01 <0.01 <0.01 Fluoride mg/l 0.05 <0.05 < < Chloride mg/l Nitrate mg/l <0.1 <0.1 < <0.1 Sulphate mg/l Escience Associates (Pty) Ltd Page 15

22 Table A - 6: Leaching results of samples WR1 to WR8 Analyte Name Units Reporting Limit WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailings Extraction Fluid # 0 Final ph Silver mg/l <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 Arsenic mg/l <0.003 <0.003 <0.003 <0.003 <0.003 <0.003 <0.003 <0.003 Boron mg/l <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 Barium mg/l < Beryllium mg/l <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 Bismuth mg/l <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Cadmium mg/l <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 Cobalt mg/l < < <0.002 Chromium mg/l < Copper mg/l < < Mercury mg/l < < < < < Lithium mg/l 0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 <0.04 Manganese mg/l < < Molybdenum mg/l <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 < Nickel mg/l < <0.007 <0.007 < <0.007 Lead mg/l <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 Antimony mg/l <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 Selenium mg/l <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 Tin mg/l <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 Strontium mg/l < < Vanadium mg/l <0.003 < Zinc mg/l <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 Zirconium mg/l <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 <0.007 Aluminium mg/l < Calcium mg/l 0.5 < <0.5 <0.5 2 Iron mg/l 0.05 < <0.05 <0.05 < <0.05 <0.05 Escience Associates (Pty) Ltd Page 16

23 Table A - 6: Leaching results of samples WR1 to WR8 Analyte Name Units Reporting Limit WR9 WR10 WR11 WR12 WR13 WR14 WR15 Tailings Potassium mg/l Magnesium mg/l Sodium mg/l < Silicon mg/l Titanium mg/l <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 Hexavalent Chromium mg/l <0.01 <0.01 < <0.01 Fluoride mg/l < <0.05 <0.05 < Chloride mg/l Nitrate mg/l 0.1 <0.1 < < Sulphate mg/l Escience Associates (Pty) Ltd Page 17