AngloGold Ashanti Australia Ltd (AGAA) has announced that the partners in the Tropicana Joint Venture have approved Phase One of the Long Island strategy, increasing production from the mine in the medium term and extending mine life.
Long Island has been driven by developing a more cost-effective way to mine waste. It involves using a strip-mining approach that minimises waste haulage distances by using in-pit backfill, rather than trucking the material long distances to surface waste dumps.
The Tropicana gold mine, located 330 km east-northeast of Kalgoorlie in Western Australia, is owned by AGAA (70% and manager) and Independence Group NL (30%).
Phase One of Long Island comprises mining of the Havana South pit and a cutback of the Boston Shaker pit, which uses the completed Tropicana pit as the first backfill location.
The full Long Island strategy adds 2.1 million oz to Tropicana’s business plan, extending mine life by approximately seven years to 2027. The project value has been enhanced by the decision to install a 6MW ball mill in the processing plant, enabling throughput to be matched to the increased mining rate and improving gold recovery by 3% to approximately 92%.
Grade streaming, which prioritises the processing of higher-grade ore and stockpiling lower-grade material for processing at a later date, has resumed at Tropicana and will continue through 2018 and 2019. Gold production (100%) is forecast to be between 478,000oz and 492 000 oz next year and between 530 000 – 548 000 oz in 2019.
“This project is in line with our approach of developing cost-effective brownfield projects with attractive payback periods that extend life and improve margins,” said Michael Erickson, AngloGold Ashanti’s Senior Vice President Australia. “The project validates the innovative ideas developed by our site team and technical specialists, and also gives us an excellent base from which we can investigate adding additional value through underground mining opportunities and regional exploration.”
Gold production over Tropicana’s remaining life of mine is now forecast to be about 4 million oz. This does not include potential future underground production from mineralization at the Boston Shaker ore body, which remains open at depth. A pre-feasibility study on underground mining will be commissioned in 2018.