Resolute Mining Ltd. said July 3 that an updated definitive feasibility study for an underground operation at the Syama gold mine in Mali extended the mine's life to 16 years at a reduced all-in sustaining cost of US$746 per ounce of gold.

Under the original definitive feasibility study in June 2016, the ASX-listed gold miner estimated a 13-year mine life, with all-in sustaining cost at US$881 per ounce of gold.

The updated study took into account a June underground reserve estimate update, in the probable category, of 3.0 million ounces of gold contained in 35.2 million tonnes grading 2.7 g/t gold.

Preproduction CapEx increased to US$116 million, from US$95 million, with preproduction operating expenses reduced to US$11 million. Sustaining CapEx fell to US$255 million, from US$270 million.

"Our study focus at Syama will now turn to identifying the optimal future mining rate ... There is obvious scope to increase the current planned mining rate of 2.4 million tonnes per annum to as much as 4.0 million tonnes per annum," said Managing Director and CEO John Welborn in a statement.

In June, Resolute entered into a strategic framework agreement with Sweden-based Sandvik Mining and Rock Technology to fully automate underground operations at its Syama mine. The automated system, including automated trucks and electrical loads, is scheduled for commissioning near the end of this year.