OwnershipIGO 30% (AngloGold Ashanti: 70% and manager).
Location330km ENE of Kalgoorlie.
Tropicana is located on the western edge of the Great Victoria Desert of which the traditional owners and custodians emanate from the Wongatha and Spinifex peoples.
Figure – Location of Tropicana Gold Mine tenure
IGO targeted and pegged the area containing the current ore reserves in 2001. AngloGold Ashanti farmed into the project in 2002, discovering the Tropicana Operation, Havana and Boston Shaker gold deposits respectively in 2005, 2006 and 2010. The decision to develop the Tropicana Operation was announced in November 2010 following completion of a positive Bankable Feasibility Study. Mining of the Havana deposit commenced in 2012 with the first gold being produced in September 2013. In January 2018, the Tropicana Operation achieved its two million ounce milestone.
The Tropicana joint venture concession packages comprise approximately 3,600km2 of tenements stretching over some 160 kilometres in strike length along the Yilgarn Craton and Fraser Range Mobile Belt Collision Zone. Tropicana lies to the west of a major tectonic suture between the Yilgarn Craton and the Proterozoic Albany-Fraser Province that stretches over 550km. The majority of the project covers tectonically reworked Archean rocks which form the eastern margin of the Yilgarn Craton. The regional geology is dominated by granitoid rocks, felsic to mafic paragneiss and orthogneiss, and felsic to ultramafic intrusive and volcano-sedimentary rocks. Tropicana is a rare example of a large gold deposit within high grade metamorphic rocks that have undergone widespread recrystallisation and melting.
Open pit mining operations achieved a 6% increase in tonnes mined over the previous year with 87.0 million tonnes, equating to 33.7 million bank cubic metres for the year. The ramp-up in mining rates is aligned to the Long Island Mining Strategy which was approved during FY18. The strategy involves using a strip-mining approach that minimises waste haulage distances by using in-pit waste dumping along with the implementation of a CAT 6060 (600 tonnes class) hydraulic shovel.
Photo - Tropicana Gold Mine
The mill throughput rates now average 931 tonnes per hour, with the optimisation excellence project producing sustainable throughput increases achieving 7.8 million tonnes per annum for the FY18 year. Construction on the second 6 mega watt ball mill progressed during the year, with the expected installation to be completed by December 2018 and operational from January 2019. The new mill will enable processing throughput rate to be increased to approximately 8.2 million tonnes per annum and gold recovery to be improved by up to 3% to approximately 92%.
Tropicana Operation gold production for FY18 was consistent, resulting in delivery better than the midpoint of the guidance range.
During the year, a total of 87.0 million tonnes of material was mined and hauled ex-pit. This material comprised of 9.6 million tonnes of full grade ore (>0.6 grams per tonne), 0.9 million tonnes of marginal ore (grading between 0.4 & 0.6 grams per tonne Au) and 76.5 million tonnes of waste material.
Full grade ore sources were from all four pits, being the Havana and Havana South pit, the Boston Shaker pit and the Tropicana Operation pit with the average run-of-mine grade for full grade ore (>0.6 grams per tonne Au) being 1.88 grams per tonne Au for the year.
Tropicana Gold produced - 100% basis: 500,000oz to 550,000oz
Tropicana Gold produced - IGO 30% share: 150,000oz to 165,000oz
Cash cost A$635 to A$705/oz Au
All-in Sustaining Costs A$890 to A$980/oz Au
Tropicana FY19 guidance incorporates continued implementation of the Long Island mining strategy, grade streaming and ongoing process plant improvement projects. The grade streaming strategy which delivers higher gold production in FY19 is expected to continue into FY20. The majority of plant and equipment capex is anticipated to be improvement capex. This includes completion expenditure for the additional 6MW Ball Mill and associated infrastructure, which is expected to be completed in 2Q19, Long Island expansion capital, plant improvement capital and Boston Shaker prefeasibility study costs.
Boston Shaker Underground Potential
A Prefeasibility Study on the underground development of Boston Shaker mineralisation is scheduled for completion by December 2018. As part of this study a 100 metres x 100 metres drilling program to define the geometry of the high-grade mineralisation has continued to extend mineralisation downdip to approximately 700 metres. Mineralisation remains open.
Greenfields exploration drilling completed on several Tropicana tenements in FY18 mapped basement geology and explored potential mineralised corridors identified in regional interpretation work. The FY18 (100%) spend was $10.3 million. The JV exploration plan for FY19 is to focus on nearmine resource and reserve development support and greenfields discovery work.
Figure - Tropicana Joint Venture tenure (IGO – 30%)