One of Australia's top five gold mines, Tropicana transitioned from large scale open pit mining to a combination of open pit and underground mining in 2020 when the Boston Shaker underground mine started ore production.
The site has produced 4Moz since it began operations.
Open pit mining uses conventional drill and blast methodology with total annual movement of ore and waste of approximately 90 Mtpa. The open pit mining strategy at Tropicana has been designed to optimise cash flow, NPV and delivery of ore. This strategy resulted in the decision in 2021 to go ahead with a final cutback of the Havana pit. The Havana cutback will generate a further 32 million tonnes of ore for 1.4Moz of gold, extending mine life from 2027 to 2030.
Labour shortages and equipment reliability impacted waste stripping in the Havana cutback in 2022, which has the potential to push peak ore production from the Havana open pit from 2025 into 2026. Operational measures are in place to pull back this deficit in waste stripping.
The Boston Shaker underground mine achieved steady state production of 1.4 Mt of ore per annum in early 2022 and is scheduled to rise to approximately 2 Mtpa. Underground mining uses mechanised jumbo development and open stoping methods.
A prefeasibility study was underway at the end of 2022 on mining the underground mineralisation at Havana. The PFS is assessing the most economical way to access the ore, ether via a dedicated decline from the Havana pit, or via the "Havana Link Drive" from the current Tropicana decline. The Havana Link Drive has the potential to provide a drilling platform to access high grade mineralisation between Tropicana and Havana, and potentially early access to the Havana underground. The PFS will be completed in 2023.
The processing plant has a throughput capacity of ~9 Mtpa. The crushing circuit consists of a primary gyratory crusher feeding a set of secondary cone crushers and tertiary high pressure grinding rolls. A 14MW ball mill and a 6MW ball mill operating in parallel complete the circuit.
Exploration at the site remains focused on testing for extensions of underground mineralisation at Boston Shaker, Tropicana and Havana and on regional targets.