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 decision by the Joint Venture partners to develop the Tropicana gold mine was announced to the market in November 2010 following a positive Bankable Feasibility Study. In early 2011, construction of the 220km access road commenced, followed by development of site infrastructure including an aerodrome, accommodation village, borefields and processing plant. Mining of the Havana deposit commenced in 2012 with the first gold was poured in September 2013.
The Tropicana and Salt Creek joint venture concession packages comprise approximately 3,200km2 and 2,300km2 of tenements respectively stretching over more than 250 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 using a fleet of three Caterpillar excavators and fifteen 793 Caterpillar trucks and other support equipment. Mining is undertaken on 10m benches. Ore is hauled directly by truck either to the primary crusher or to ore stockpiles.
Photo - Tropicana Gold Mine
The Tropicana processing plant has a name plate capacity of 5.8Mtpa and comprises crushing, High Pressure Grinding Rolls, one stage grinding and CIL recovery. Optimisation and upgrade of the process plant due for completion in September 2016 is targeted to achieve a throughput rate of 7.5Mtpa.
Photo - Tropicana Gold Mine gold room
Tropicana gold production for FY16 was in line with expectation at 448,116oz (on a 100% basis) and cash costs and All-in-Sustaining Costs (AISC) were $730/oz produced and $918/oz sold respectively. During the year, a total of 24.6M bank cubic metres of material were mined and hauled ex-pit. This material comprised of 7.3Mt of full grade ore (>0.6g/t), 1.2Mt or marginal ore (grading between 0.4 & 0.6g/t Au) and 50.3Mt of waste material. Full grade ore sources were the Havana Pit (4.47Mt), the Boston Shaker Pit (0.82Mt) and Tropicana (2.0Mt) with the average run-of-mine grade for full grade ore (>0.6g/t Au) being 2.13g/t Au for the year. A total of 6.53Mt of ore at an average grade of 2.39g/t Au was processed during the year. Average metallurgical recovery was 89% for 448,116oz of gold produced. The reduction in gold production for the year compared to the FY15 (496,413oz) is a result of the cessation of grade streaming in December 2015. Gold production is forecast to trend to long term guidance of 400,000oz/pa once expansion of the process plant to 7.5Mtpa is achieved. IGO's attributable gold production during FY16 was 134,435oz and IGO's attributable share of gold refined and sold was 135,864oz. IGO's attributable average cash costs for FY16 were $730/oz Au produced and AISC were $918/oz Au refined.
Attributable gold production during FY17 to IGO’s account is expected to be in the range of 117,000oz to 129,000oz with cash costs plus royalties in the range of $850 to $950/oz and all-in sustaining costs in the range of $1,150 to $1,250/oz. IGO’s share of sustaining and exploration capital is expected to be in the range of $2 to $3 million and $2 to $3 million respectively.
Figure – Proposed gas pipeline construction (in red)
In 2014, AngloGold Ashanti, on behalf of the Joint Venture, entered into agreements with APA Group (APA) for the transportation of natural gas to Tropicana. Under the agreements APA would construct a new 292km gas pipeline which will connect Tropicana with APA’s Goldfields Gas Pipeline and Murrin Murrin lateral. The gas pipeline project including the installation of the gas fired generators is complete with the commissioning of the 17 gas fired generating units. Further cost savings resulting from this project will be achieved as site equipment requiring LNG as fuel is progressively upgraded to operate on natural gas.
A 3D seismic program completed during FY2015 identified a number of potential targets down dip and along strike of known resources. Drilling is currently testing these and other targets identified in previous drilling to add to resources and extend the mine life.
Figure -Tropicana Gold Project - Boston Shaker, Tropicana, Havana and Havana South open pit outlines
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 be within trucking distance of the Tropicana Mine.
Figure - Tropicana Joint Venture tenure (IGO – 30%)