Metminco Limited (LON:MNC ASX:MNC) has hinted it may go underground at its newly acquired Miraflores deposit in Colombia.
“The decision on the development option will take cognisance of community and environmental factors, as well as financial factors.
“The smaller surface footprint of the underground only mining option remains a very attractive option," said managing director William Howe.
Howe was commenting after the explorer published an updated JORC-compliant resource estimate for Miraflores.
Using a much higher cut-off grade of 1.2g/t gold, the deposit is now estimated to contain 9.19Mt at 2.81g/t gold and 2.76g/t silver in the measured and indicated category. Of that 2.95Mt was in the measured category.
The previous NI 43-101 resource was 72.6Mt at a gold and silver grade of 0.78g/t and 1.52g/t respectively, using a cut-off grade of 0.27g/t gold.
Metminco added that it had asked MMC, which produced the updated resource estimate, to estimate an underground-only version.
On that basis, Miraflores has 832,000oz of gold and 817,000 silver in the M&I categories at the same cut-off.
Consultant SRK is also working on a revised mine plan schedule for the underground mine.
William Howe, managing director, said: "This resource statement and the pending mine plan will allow the company to fast track the completion of the Feasibility Study.
A final decision on whether the mine will be developed as a stand-alone underground operation or a combination of an open pit and underground mine as previously contemplated, will be taken once the revised underground mine plan has been completed.
The decision on the development option will take cognisance of community and environmental factors, as well as financial factors. The smaller surface footprint of the underground only mining option remains a very attractive option."