MEMORANDUM BARRICK GOLD

Barrick Technology Centre

T E L (604) 682-1730 F A X (604) 682-1767323 Alexander Street

Vancouver, British Columbia www.barrick.com

Canada V6A 1C4

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Gold Grains size accumulated distribution (weight %)

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9.68.16.85.74.84.13.42.82.421.751.451.210.870.730.620.520

Passing Size (um)

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Figure 1: Gold grains size accumulated distribution. (Uneven curve caused by nugget gold grains and insufficient gold grain numbers.) 3.5.2 Gold species and associations More than 99 % of gold is native gold, with 92-99 % of Au and 1-8 % Ag. Less than 1 % of the gold is copper silver gold. Table 1 and Figure 2 shows that 73 % of gold is exposed, 12 % locked in FeOx which may be leachable, 10 % locked in quartz, and 5 % locked in others (mainly rutile and alter-ilmenite). It is expected maximum leachable gold is 85.6 % (liberated, gold in FeOx plus exposed gold). Due to insufficient gold grain counts in the coarse fraction (+0.250-0.840 mm and +0.840 mm), the actual maximum leachable gold may be higher than 85.6 %.

Table 1: Gold locking result (%) Size Fraction -0.106 mm +0.106-0.250mm +0.250-0.840mm +0.840mm Calcd head

Liberated 18.2 4.7 0.0 25.2 16Exposed (attached to Qz) 7.6 48.5 48.2 41.7 37Exposed (attached to FeOx) 55.2 25.3 0.0 0.0 12Exposed (attached to Rutile) 13.5 0.0 6.5 7.8 8

Locked (in Qz) 2.3 8.8 5.1 15.4 10Locked (in FeOx) 0.5 10.6 38.3 2.5 12Locked (in Rutile) 2.6 2.2 1.8 7.2 5Total 100 100 100 100 100

MEMORANDUM

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Gold Distribution

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Exposed(attached toFeOx)

Liberated

Figure 2: Gold locking distribution (%)

MEMORANDUM

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3.5.3 Gold bearing particle image from MLA

Gold MineralsSilver MineralsOther Sulphides/FeOxSilicates (Quartz)Others (Rutile/alt_ilmenite)PyriteHeavy minerals (Hg-minerals)Carbonates

-0.106 mm Fraction

-0.250+0.106 mm Fraction

+0.840 mm Fraction-0.840+0.250 mm Fraction

Exposed gold

Gold locked in quartz

Gold locked in FeOx

Gold locked in rutile

Figure 3: Gold bearing particle image from MLA

MEMORANDUM

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4 CONCLUSION Quartz is the dominant mineral (97.3%), followed by trace amount of other silicate mineral, rutile, goethite, zircon, alter-ilmenite, pyrite, copper sulphide, barite, jarosite and cinnabar. 97.8% of silver minerals are associated with quartz. 89.1 % of the silver is locked within the quartz, whilst 8.7 % are exposed but attached quartz or in pores/cracks of the quartz. 1.7 % of silver minerals are liberated, and remained 0.5% of silver minerals are locked in other mineral. The average silver grain size is 1.0 µm. 42% (weight) of silver mineral grains are finer than 1 µm. The quartz matrix contains pores ranging in size from <0.1 µm to several micrometers. The majority pores are small (<2 µm), and about 89.6% of silver is not exposed, suggesting the maximum leachable silver would be 10.4% for the -2 mm Veladero Type 1 ore. Silver minerals occurs mainly as 32% of Acanthite (Ag2S), 23% of silver copper sulphide, 24% of Capgaronnite (HgAgClS), and 11% of Schachnerite (Ag1.1Hg0.9), in minor amounts 4% of Lenaite (AgFeS2) and 3% of (AgCuHgFe)2S, and in trace amounts as alloy (AgCd), Aguilarite (Ag4SeS), Chloragyrite (AgCl), Geffroyite (Ag,Cu, Fe)9(Se,S)8), Naumannite (Ag2Se) and silver. Average of the gold grains size is approximately 2 µm. 14 % (weight) of gold grain size is finer than 1.0 µm. 73% of gold is exposed, 10 % of gold is locked in quartz, 12 % of the gold is locked in FeOx which may be leachable, and 5% locked in others (mainly rutile and alter-ilmenite). Maximum leachable gold is likely to be 85.6% (liberated, exposed plus locked in FeOx). Due to a low gold count in the coarse fraction, the actual maximum leachable gold may be higher than 85.6 %. More than 99 % of gold species is native gold, which contains 92-99 % of Au and 1-8 % Ag. Less than 1 % of the gold is copper silver gold.