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Tasiast Exploration
Little exploration has been undertaken at Tasiast since 2003 and has in the past been largely focused on the resource areas.
The Company intends to progressively increase the scope of exploration at Tasiast in the following way:
- Complete 15-20,000m of resource infill drilling to complete the evaluation of the Piment and West Branch structures to allow resources and reserves to be re-estimated.
- Expansion of the drilling programme to investigate as yet un-tested sections of the host structures along strike of the known mineralisation.
- Evaluation of the numerous outlying prospects within the 312sqkm Mining Lease that have received only limited drilling in the past.
- Commencement of exploration within the 5,994sqkm exploration package that surrounds the mining lease.
Positive Leach Testing of Low Grade Material
Ongoing test work at Tasiast is showing that lower grade resource ounces may be recoverable by conventional "dump" or "heap" leaching. This would have a positive impact on reserves, annual production and economics at Tasiast.
Initial column tests have been conducted on oxide ball mill feed (-20mm) and RC chips (66% -1mm) from the Piment Zone, where mining is ongoing. Recoveries achieved were 82.3% and 89.4% respectively. Based upon these results two pilot dump leach pads have been constructed at site using lower grade material.
The first pad, containing an estimated 1,648 tonnes of oxide material at 1.30 g/t, has been under leach for 22 days with an indicated recovery of 50.6% achieved to date. The second pad, comprising an estimated 2,692 tonnes of oxide material grading 1.13g/t, will commence leaching by the end of June. In parallel with this on-site testing, samples are also being sent to Kappes Cassiday Associates in the USA for independent confirmation.
These preliminary results indicate that the oxide material tested leaches rapidly and is very amenable to dump and heap leaching. A core drilling program will commence in June to provide representative samples from other deposits at Tasiast, including West Branch.
A heap/dump leaching option at Tasiast would have a significant and positive impact on operations. The table below shows the increase in resources at Tasiast at lower cut off grades:
Tasiast Resources remaining at December 2007
Cut-Off |
Measured |
Indicated |
Measured + Indicated |
Inferred |
Mt |
Au g/t |
Oz |
Mt |
Au g/t |
Oz |
Mt |
Au g/t |
Oz |
Mt |
Au g/t |
Oz |
0.3 |
21.53 |
1.54 |
1.07 |
49.38 |
1.06 |
1.68 |
70.92 |
1.21 |
2.75 |
36.87 |
0.92 |
1.08 |
0.5 |
17.62 |
1.80 |
1.02 |
36.11 |
1.30 |
1.51 |
53.73 |
1.46 |
2.53 |
24.63 |
1.17 |
0.93 |
0.8 |
13.06 |
2.20 |
0.92 |
21.98 |
1.73 |
1.22 |
35.05 |
1.91 |
2.15 |
13.40 |
1.63 |
0.70 |
1.0 |
10.83 |
2.47 |
0.86 |
16.36 |
2.02 |
1.06 |
27.19 |
2.20 |
1.92 |
9.49 |
1.93 |
0.59 |
Note: Piment Zone as at 31 December 2007, West Branch updated June 2008.
Exploration Potential Along Strike
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Gold Prospect Map
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Tasiat Prospects
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