CMD Gold Mine
Lachlan Star Limited (Lachlan) has 100% beneficial ownership of the CMD Gold Mine, located in Andacollo approximately 350km north of Santiago (Fig 1).
Figure 1 – CMD Gold Mine Location
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The CMD Gold Mine is an operating open pit heap leach gold mine that commenced production in 1995 and has produced approximately 850,000 ounces of gold since operations commenced. The CMD Gold Mine is located immediately adjacent (100m) to the large Carmen Andacollo copper gold mine owned by Teck that is forecast to produce 80,000 tonnes of copper and 60,000 ounces of gold per annum over a mine life in excess of 20 years.
The assets of the CMD Gold Mine include:
- Existing unhedged gold production (circa 50,000 ounces per annum);
- NI 43101 Indicated mineral resources of 0.46 million ounces of gold at an average grade of 0.6 g/t gold and a further Inferred mineral resource containing 0.98 million ounces of gold at an average grade of 0.7 g/t gold;
- Excellent exploration potential to define significant resources as the known mineralisation is open either along strike, or at depth, or both;
- Underutilised 8Mtpa production facility currently running at 3.6Mtpa run rate;
- 100 tpd ball mill and CIL circuit;
- Water rights in excess of that required for production and
- Carry forward tax losses of approximately US$75 million and a capital repatriation credit of approximately US$85 million2
Figure 2 below shows the location of the CMD Gold Mine (inside the red outline) and the adjacent Teck Andacollo operation. The Las Loas pits are located approximately 5km north of the heap leach facility, whilst the remaining CMD Gold Mine deposits are all located within 3km of the heap leach facility.
Figure 2 – CMD Gold Mine
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Figure 3 below shows the crushing circuit and view over the Tres Perlas and Churrumata pits towards the Teck Andacollo mine from the heap leach pads.
Figure 3 – Crushing Plant and Pits
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Mineral Resources and Exploration
Table 1 contains the mineral resource estimates as at 1 August 2011.
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CMD Mineral Resources (August 2011) above 0.3 g/t Au |
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Deposit |
Indicated |
Inferred |
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Tonnes(Mt) |
Grade(Au) |
Ounces(Kozs) |
Tonnes(Mt) |
Grade(Au) |
Ounces(Kozs) |
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Las Loas |
2.9 |
0.8 |
73 |
1.5 |
0.8 |
37 |
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El Sauce |
7.1 |
0.7 |
156 |
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Toro/Socorro |
3.3 |
0.8 |
84 |
8.1 |
0.7 |
188 |
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Tres Perlas |
15.6 |
0.5 |
252 |
19 |
0.5 |
333 |
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Churrumata |
0.6 |
0.8 |
16 |
8.7 |
0.8 |
219 |
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Chisperos |
1.0 |
1.1 |
36 |
1.4 |
1.0 |
43 |
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Total |
23.4 |
0.6 |
461 |
46.3 |
0.7 |
976 |
In addition to the mineral resources in Table 1, there is a significant amount of mineralisation that is yet to be incorporated into a NI 43101 compliant mineral resource estimate.
Exploration under the previous private owners has been limited for the last 7 years, during which time the gold price has increased dramatically. The Company has commenced an aggressive exploration program with a view to increasing the current mineral resource base to provide a platform from which to fill the plant to capacity, with a total of 33,000 m of drillingdrilling planned for calendar 2011.
Mining and Processing
Mining of the deposits is via conventional open pit mining using contractors. The previously short term mine planning has led to certain operational inefficiencies that are currently being optimised. Daily movement rates are in the order of 50,000 to 60,000 tpd from all pits, with the Churrumata, Tres Perlas, Toro, Chisperos and Las Loas pits providing ore presently.
Ore is three stage crushed and stacked onto a large heap leach pad to recover the gold.
Mine planning work is underway for each of the mineral resources to determine the optimal size of each pit, with the aim being to generate a significant tonnage of ore available for mining at higher throughput rates than the current level of 3.6Mtpa (as of October 2011).