Newmont Mining Corp. achieved commercial gold production at the Twin Creeks Underground mine, part of its Nevada Operations.

The company said July 3 that the expansion project was completed on schedule for US$42 million, below its guidance of between US$45 million and US$55 million.

Twin Creeks Underground is expected to increase annual gold production by between 30,000 and 40,000 ounces, with all-in sustaining costs of between US$650/oz and US$750/oz for the first five years of operations.

Newmont said the new ore will also enable the processing of stockpiles previously classified as waste material and will extend processing to 2030.

The company plans to blend ore from Twin Underground with ore from its Turquoise Ridge joint venture with Barrick Gold Corp.