PERTH (miningweekly.com) – Commercial production has been declared at the Boston Shaker underground mine, at the Tropicana gold joint venture (JV) in Western Australia.

Development of the underground operation was approved in March last year, and the mine transitioned to commercial production on schedule, and below the A$105.7-million budget set by JV partner AngloGold Ashanti and Independence Group.

The underground mine is expected to produce 1.1-million tonnes of ore, containing some 100 000 oz/y of gold over a seven-year mine life.

“Underground mining at Boston Shaker will leverage further value from this high-performing operation, achieving payback in just over three years, with upside potential as the deposit remains open at depth,” said AngloGold Ashanti senior VP for Australia, Michael Erickson.

“The underground mine will contribute higher grade mill feed from the current quarter onwards, improving the gold production profile and enhancing cash flow during calendar 2021 to 2023, when the mine plan includes periods of higher waste stripping in the Havana openpit.”

Independence MD and CEO Peter Bradford said that the completion of the underground mine was an exciting milestone for the JV partners.

“Unlocking value at Tropicana has remained a key focus for the JV throughout Tropicana’s long and successful history. We are confident that the success achieved at Boston Shaker will serve as a template for the potential development of additional underground mines at Tropicana over the coming years.”

Bradford noted that in addition to the potential for resource extensions at depth at Boston Shaker, known extensions of mineralisation beneath both the Tropicana and Havana openpits also offered further underground potential. 

Development from an underground drill drive from the Boston Shaker decline has completed some 240 m to date, and could provide production access to Tropicana underground, should drilling and studies prove successful and a decision to mine is made. Underground diamond drilling is scheduled for the December quarter, and a decision to mine is expected in 2021.

A decision was made in June this year to invest in the next cutback of the Havana pit, allowing for access to deeper openpit ore from 2022 onwards, and final trade-off studies are being completed on the Havana Stage 3 openpit cut-back and on the Havana underground operation, to determine the optimal openpit/underground interface. A decision on the way forward for the Stage 3 operation is expected to be made in 2021.

Independence recently announced a strategic view into its 30% interest in the Tropicana JV, after the company received unsolicited approaches from a number of parties.