Northern Star will spend $43 million expanding the capacity of its Pogo goldmine in Alaska by 30 per cent.
The ASX-listed miner will start work in the current financial year and complete the expansion early in the 2021 calendar year, increasing Pogo's annual throughput capacity from 1.0 million tonnes to 1.3 million tonnes.
Northern Star on Monday said the decision to expand was taken after mining rates increased following a change in mining method, implementation of a new mining fleet and the upgrading of Pogo's resources and reserves.
In July, Northern Star announced new quarterly and annual sales records thanks to continued progress at Pogo.
"The extensive changes we have implemented and our ongoing optimisation program, including the introduction of long-hole stoping and the use of bigger, more efficient mobile mining equipment, have been highly successful," executive chairman Bill Beament said.
"With this confidence in the mining operation now well-established, we will move quickly to begin expanding the plant, driving further efficiencies in the process."
At 1137 AEST, shares in Northern Star were 3.95 per cent higher at $10.79.