Ownership IGO 30% (AngloGold Ashanti: 70% and manager).
Location 330km 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 gold reserves in 2001. AngloGold Ashanti farmed into the project in 2002, discovering Tropicana, Havana and Boston Shaker Gold Deposits respectively in 2005, 2006 and 2010. The gold deposits occur over a 5km strike length with gold mineralisation intersected over 1km vertically beneath the natural surface.
The Tropicana gold mine commenced production 2013 and in early 2018 reached the two million ounce production 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.
The Tropicana gold mine comprises an open pit mining operation with production from up to four contiguous pits extending some five kilometres in strike length. Mining is carried out by Macmahon Holdings Limited under an alliance contract delivering ore directly by truck either to the primary crusher or to ore stockpiles.
During 2016 and 2017, the joint venture partners carried out a program of work to understand the potential beneath the original pit designs, resulting in the evolution of what is known now as the Long Island Project.
In short, strip mining and in-pit dumping of waste, as commonly used in the coal mining sector, will be used to reduce mining costs to allow deeper mineralisation to be mined, thereby extending mine life, without significant impact on operating margins. The joint venture partners approved this project strategy in December 2017
As noted previously, this approach considers a strip mining technique more commonly used in the coal mining industry that has the effect of reducing waste haulage distance by backfilling areas previously mined and hence lowering the mining cost. The study is expected to be completed in the December 2017 quarter.
Photo - Tropicana Gold Mine
Since commencement of operations in 2013, the joint venture partners have continued to invest in the process plant optimisation projects to increase throughput rate from the original 5.8Mtpa nameplate capacity to around 8Mtpa.
Further capital expenditure is being invested in 2018 to install a second ball mill. This work will be completed in late 2018 and is expected to increase throughput by 5% and metallurgical gold recovery by 3%.
Photo - Tropicana Gold Mine
Attributable gold production during FY18 to IGO’s account is expected to be in the range of 132,000oz to 147,000oz with cash costs plus royalties in the range of $680 to $750/oz and all-in sustaining costs in the range of $1,060 to $1,170/oz. IGO’s share of sustaining and exploration capital is expected to be in the range of $4 to $6 million and $16 to $18 million respectively.
Boston Shaker Underground Potential
Framework drilling and scoping studies in late 2017 and early 2018 identified the opportunity for potential underground mining at Boston Shaker resulting in the commencement of a pre-feasibility study and an infill drilling program. This work is ongoing and expected to be completed in late 2018.
Regional exploration continues to identify and test numerous prospects away from the immediate mine area. AngloGold Ashanti have prioritised geological and structural targets in prospective domains and rock packages to ensure targeted exploration. The extent of the exploration tenure is such that any discoveries made by regional exploration will likely be within trucking distance of the Tropicana Mine.
Figure - Tropicana Joint Venture tenure (IGO – 30%)