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Tasiast Gold Mine
Tasiast Reserves
The Company's consultants, AMC Consultants, re-estimated Ore Reserves for the Tasiast mine as at December 31, 2009.
Classification |
Tonnes |
Au |
In situ Au |
(Mt) |
(g/t) |
(Moz) |
Total Proven |
49.4 |
1.36 |
2.17 |
Total Probable |
61.5 |
1.40 |
2.77 |
Total Stockpile |
4.3 |
0.68 |
0.09 |
Total |
115.2 |
1.36 |
5.03 |
- Numbers may not add correctly due to rounding
- The Ore Reserve estimate used a gold price of US$800
- Cut-off grades: CIL: oxide 0.75g/t, fresh 0.81g/t.
- Cut-off grades: Dump leach oxide cut-off grade is variable depending on lithology with the lowest being 0.1 g/t.
The estimated split of the current Reserve by processing method (excluding heap leaching) is set out below:
Classification |
Tonnes |
Au |
In situ Au |
(Mt) |
(g/t) |
(Moz) |
CIL Circuit |
|
|
|
Proven |
30.2 |
1.98 |
1.92 |
Probable |
39.8 |
1.96 |
2.51 |
Stockpile |
0.6 |
1.48 |
0.03 |
Total CIL Circuit |
70.7 |
1.96 |
4.46 |
|
|
|
|
Dump Leach |
|
|
|
Proven |
19.2 |
0.4 |
0.24 |
Probable |
21.7 |
0.37 |
0.26 |
Stockpile |
3.7 |
0.54 |
0.06 |
Total Dump Leach |
44.5 |
0.40 |
0.57 |
- Numbers may not add correctly due to rounding
- Oxide ore between the cut-off grade, which is dependent on lithology and the lowest being 0.1 g/t and 0.9 g/t was allocated to the Dump Leach Process.
The independent Ore Reserve estimate reported was undertaken under the supervision of Patrick Smith (Member of the Australasian Institute of Mining and Metallurgy), Principal Mining Engineer of AMC Consultants Pty Ltd with more than five years experience in Ore Reserve estimation. For the purpose of reporting under National Instrument 43-101 Patrick Smith is regarded as a Qualified Person.
Tasiast Resources
Since the previous December 2009 Mineral Resource estimation (February 1, 2010 release) the Measured and Indicated Resource at Tasiast has increased by 2.74Moz to 9.25Moz (a 42% increase) and the Inferred Resource has increased by 0.63Moz to 1.93Moz (a 48% increase) (at cut off grades of 0.2g/t for oxide and 0.5g/t for fresh material).
Tasiast Resources (August 2010)
| Zone |
Cut-Off |
Measured |
Indicated |
Measured + Indicated |
Inferred |
| Mt |
Au g/t |
Moz |
Mt |
Au g/t |
Moz |
Mt |
Au g/t |
Moz |
Mt |
Au g/t |
Moz |
| Oxide |
0.2 |
28.89 |
0.72 |
0.67 |
17.93 |
0.65 |
0.37 |
46.82 |
0.69 |
1.04 |
5.5 |
0.6 |
0.11 |
| Fresh |
0.5 |
68.99 |
1.64 |
3.63 |
79.44 |
1.79 |
4.57 |
148.43 |
1.72 |
8.20 |
35.6 |
1.6 |
1.82 |
| Total |
|
97.88 |
1.37 |
4.30 |
97.37 |
1.58 |
4.95 |
195.25 |
1.47 |
9.25 |
41.2 |
1.5 |
1.93 |
| |
| All ore types |
1.0 |
44.94 |
2.25 |
3.26 |
50.20 |
2.47 |
3.99 |
95.14 |
2.37 |
7.25 |
19.9 |
2.3 |
1.48 |
- The Company reports resources on the basis of mining cut-off grades to be applied to the various ore types and, for comparison purposes, at a 1.0 g/t cut-off grade
- Minerals Resources are reported below the July 31, 2010 mined surface.
- Figures may not add correctly due to rounding.
- Oxide is referred to as material amenable to Dump Leaching and CIL. Fresh is referred to as material amenable to Heap Leaching and CIL.
- The resources are estimates of recoverable tonnes and grades using Multiple Indicator Kriging with block support correction into 15 metres (East) by 25 metre (North) by 5 metre (Elevation) model blocks and assuming smallest mining unit for ore selection in mine grade control of 3 metres (East) by 5 metres (North) by 2.5 metres (Elevation).
- Measured resources lie in areas where drilling is available at a nominal 25 x 25 metre spacing, Indicated resources occur in areas drilled at approximately 25 x 50 metre spacing and Inferred resources exist in areas of broader spaced drilling.
- Gold estimation and model blocks were constrained within geologically derived wireframes.
The independent Resource estimate reported was undertaken by Nic Johnson (Member of the Australian Institute of Geoscientists) of Hellman and Schofield Pty. Ltd with more than five years experience in the use of geostatistics for estimation of recoverable resources in gold deposits. For the purpose of reporting under National Instrument 43-101 Mr. Johnson is regarded as a Qualified Person.
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