The Tropicana Joint Venture in Western Australia was formed in 2002 between AngloGold Ashanti Australia Ltd (70% and manager) and Independence Group NL - IGO (30%) and as of 31 May 2021, Regis Resources Ltd acquired the IGO 30% stake.
Tropicana was discovered 330 kilometres east-northeast of Kalgoorlie in 2005 after AngloGold Ashanti Australia followed up an unexplained gold-in-soil anomaly IGO had recognised in public domain regional data collected in the 1990s.
Subsequent exploration identified the Havana deposit and led to a detailed pre-feasibility study before a decision in July 2009 to commit to feasibility study based a Mineral Resource at the time containing 5.01 million ounces and an Ore Reserve of 3.3 Moz*.
The project was approved by the JV partners in November 2010, following a successful bankable feasibility study that was based on open cut mining of the Tropicana and Havana deposits, and treatment of 5.5 Mtpa of ore to deliver average gold production of 330,000 to 350,000 ounces per annum over a 10 year mine life. Start-up was targeted for the December quarter of 2013. Forecast capital costs were between A$820-$845 million.
The discovery of the Boston Shaker deposit and of mineralisation down plunge and along strike at Havana Deeps added to resources and by the end of 2012, the Measured Indicated and Inferred Mineral Resource had grown to 7.89 million ounces of gold.
By early 2012 the 220 km long new access road from Pinjin to the remote site had been completed and construction of the treatment plant was underway. Open pit mining of the Havana Starter Pit began in July 2012 and first ore was sent to the crushing circuit in July 2013.
First gold was poured on 26 September, ahead of schedule and on budget, after two and a half years of construction and eight years after the initial discovery.
The processing plant successfully achieved its ramp-up target of 95% plant availability at a throughput rate of 5.8 million tonnes per annum within six months. The plant has a current capacity of 9.3-9.5 Mtpa and the crushing circuit consists of a primary gyratory crusher, feeding a set of secondary cone crushers and tertiary roll crushers. A 14MW and 6MW ball mill in parallel complete the grinding circuit.
One of the top five gold producing operations in Australia, Tropicana transitioned from large scale open pit mining to a combination of open pit and underground mining in 2020 following development of the site's first underground mine beneath the Boston Shaker pit. It produced its 4 millionth ounce in the fourth quarter of 2022.
In June 2023, a contract was signed with Pacific Energy to construct and operate Australia's largest off-grid solar and wind implementations at Tropicana. The renewable facility will consist of 4 x 6 MW wind turbines, a 24 MW solar farm and a 14 MW battery storage system which will be integrated into the existing 54MW gas fired power system.
Overall, the renewables integration is expected to reduce Tropicana's diesel and gas consumption for power generation by 96% and 50% respectively, reducing carbon emissions by more than 65,000 tpa on average over the life of the agreement.
The project is due for completion in the first quarter of 2025.
The Havana underground feasibility study was approved in H1 2024 and portal access commenced in September 2024.
Development of a link drive to provide access to additional drill areas between Tropicana and Havana continued during 2024. The link drive is expected to ultimately link up with the Havana underground.
Open pit mining is undertaken using conventional open cut, drill and blast, followed by truck and excavator operation. Open pit mining of Boston Shaker was completed in 2022 with all activity now focused on the Havana pit, which is undergoing a series of cutbacks. The total annual movement of ore and waste is approximately 60-70 Mtpa. Underground mining uses mechanical jumbo development and open stoping methods. At peak, annual production from underground is planned to reach approximately 2Mt of ore.
*See Reserve Resource Statement for current figures and relevant JORC disclosures.
