Independence Group NL's pre-feasibility study at the Tropicana gold joint venture in Western Australia confirmed underground mining beneath the Boston Shaker open pits as a technically and financially viable option.
The joint venture, which is owned 30% by Independence and 70% by AngloGold Ashanti Ltd. unit AngloGold Ashanti Australia Ltd., will now move to a feasibility study on the Boston Shaker underground development expected to be complete in the third quarter of 2019.
The underground mine design will target a production rate of 1 million tonnes per annum of material grading 3.7 g/t to produce an average 100,000 ounces per year over a mine life of up to seven years.
The initial portal development is expected to start from within the completed Tropicana pit in mid-2019. Full production will be reached in 2021, and the last stopes are scheduled to be mined in 2026.
Capital expenditure is estimated at A$95 million, including mining development, and total operating costs are expected at A$102 per tonne.
The Boston Shaker underground indicated and inferred mineral resource stands at 10.6 million tonnes at 4.2 g/t gold containing 1.45 million ounces at a cutoff grade of 1.8 g/t gold.