TORONTO (miningweekly.com) – Africa-focused miner Mawson West on Monday said it had started underground mining at its Dikulushi copper/silver mine, in the Democratic Republic of Congo (DRC), which would extend the current mine life by nine months.

Perth, Australia-based Mawson West said underground mining was likely to extend production from the Dikulushi operations until at least the third quarter of 2014, which were expected to provide the TSX-listed firm enough time to evaluate further underground mining potential and the economic viability of identified satellite deposits.

Mawson West is currently producing copper and silver at Dikulushi by processing stockpiled material from its openpit operations, which is scheduled to continue into December. Starting underground mining will extend the mine life at about 800 t/m of copper and 65 000 oz/m of silver.

The company said it expected to extend the mine life by progressively converting the large Canadian National Instrument 43-101-compliant inferred resource, which is located below the current reserves.

Increased production rates could also be possible as Mawson West stabilised production and assessed alternative, more productive mining methods. The initial mine schedule would use about 60% of the current process plant capacity. Satellite deposits presently being evaluated could use the remaining capacity in the future.

“Dikulushi is a deposit that we know and understand. It has significant existing underground infrastructure in place, reducing the capital expenditure required to develop the project,” CEO Bruce McFadzean said.

The Dikulushi mine currently has a proven and probable reserve of 173 000 t grading 5.2% copper and 127 g/t silver. The combined measured and indicated resources totalled 365 000 t grading 7% copper and 160 g/t silver, and the inferred resources held 365 000 t grading 7% copper and 160 g/t silver.