Canada-based Kinross Gold is to begin a phase one expansion of its Tasiast gold mine in Mauritania.
The open-pit mine processes ore through an 8,000t-per-day mill and dump leach.
Kinross plans to invest about $300m to increase the mill's throughput capacity from the existing 8,000 tonnes per day (t/d) to 12,000t/d.
The capacity will be increased by the addition of a gyratory crusher, a SAG mill and three leach tanks, as well as improvements to other components of the processing circuit.
During the first ten years from 2018-2027, the new mill is expected to produce an approximate average of 409,000 gold ounces a year.
Kinross also plans to enhance incremental crushing and grinding capacity for the existing carbon-in-leach (CIL) circuits.
Phase one is expected to reach full production by the end of first quarter of 2018.
Kinross Gold president and CEO Paul Rollinson said: "This phased approach allows Kinross to transform Tasiast into a lower-cost, cash flow-positive operation in the near term, while preserving the operation's significant growth potential.
"The expansion is forecast to reduce Tasiast's production cost of sales per ounce by an estimated 48% while increasing annual production by an estimated 87% compared with 2015."
During phase two, the total throughput is expected to increase to 30,000t/d.
Rollinson added: "The two-phased approach strikes the right balance between growth and preserving balance sheet strength and is well-suited to the current gold price environment."
Phase one commissioning is expected to begin in late 2017, while full production is expected to start in early 2018.