AngloGold Ashanti and its joint venture (JV) partner Independence Group have approved a $79.3m expansion development at their Boston Shaker underground project at the Tropicana Gold Mine in Western Australia.

The project is expected to contribute to higher grade mill feed and would result in an improved gold production profile.

The underground mine plan includes periods of higher waste stripping in the Havana open pit.

Once the underground portion becomes operational, Tropicana is expected to maintain gold production between 450,000oz and 500,000oz a year over the next five years.

“An ongoing focus on operational excellence has enabled Tropicana to consistently exceed expectations.”

Boston Shaker is set to start in the June quarter of this year, with first gold scheduled for the September quarter of next year.

AngloGold Ashanti International chief operating officer Ludwig Eybers said: “Underground mining at Boston Shaker will leverage further value from this high performing operation, achieving pay-back in just over three years.

“An ongoing focus on operational excellence has enabled Tropicana to consistently exceed expectations, and I am sure this world-class performance will extend into the underground operation.”

The expanded ore production from the Tropicana Gold mine will capitalise on investments, including the second ball mill, made in the Tropicana processing plant.

The JV partners will continue to test high-grade extensions at the Boston Shaker ore body to the mineral resource beneath the Tropicana and Havana pits for evaluating the opportunity to carry out further underground mining operations.

Since the start of open-pit mining at Tropicana Gold in 2012, an underground mining contract has been awarded to Macmahon, which will operate both the open pit and underground mines.

Decline development at the project is expected to commence in the second quarter of this year and mining of the first stope is set to start in August next year.