The Tropicana Gold Project area lies east of a northeast trending magnetic feature, interpreted to be the major tectonic suture between the Yilgarn Craton and the Proterozoic Albany-Fraser Orogen that extends over 700km. The gold deposit is hosted in Archaean gneissic metamorphic rocks (ca. 2,640Ma) with cover sequences generally 10 to 30m thick resulting in the mineral deposit not being exposed at surface.

Together, the Tropicana, Havana, Havana South and Boston Shaker deposits define a northeast trending mineralised corridor, approximately 1.2km wide and 5km long that has been tested to a vertical depth of more than 1,200m. The Mineral Resource remains open down-dip from the Tropicana, Havana and Boston Shaker deposits and has the potential to be extended to the north and south. Neither the immediate metamorphic host rocks nor the mineralised zones are exposed at surface due to the presence of widespread younger cover sequences.

The Tropicana deposit comprises a mineralised zone up to 50m thick, hosted predominantly in quartzo feldspathic gneiss with a garnet-gneiss dominated hangingwall package. The mineralisation is comprised of subordinate thin (3 to 5m), discontinuous mineralised lenses that typically return intercepts of >0.5g/t gold. The Havana deposit comprises a lower, laterally continuous, higher-grade lode up to 50m thick that is overlain, in the central and southern parts of the pit, by stacked, typically lower-grade and thinner (up to 25m thick) mineralised zones. Havana is also dominantly hosted in quartzo-feldspathic gneiss, again with a garnet gneiss dominated hangingwall.

Mineralisation is accompanied by pyrite (2% to 8%) with accessory pyrrhotite, chalcopyrite and other minor sulphides and tellurides. The gold mineralisation is related to shear planes that postdate the main gneissic fabric developed during peak granulite-facies metamorphism.

Open pit mining activities are undertaken by Macmahon in an alliance partnership with AngloGold Ashanti. Mining is conventional open cut, drill and blast, followed by truck and excavator operation to develop the deposits (Havana, Havana South and Boston Shaker). The total annual movement of ore and waste is approximately 95Mtpa. Underground mining utilises mechanised jumbo development and open stoping methods. At peak production, annual production from underground is planned to reach 1.1Mt of ore. [2019, MR, p. 112]

On 28 March 2019, the Tropicana Joint Venture announced the commitment to the development of the Boston Shaker Underground mine following the successful completion of the Feasibility Study (FS). [2019, AR, p. 27]

The Boston Shaker Underground, which is being developed within the Tropicana site, is expected to be commercial production ready during the September 2020 quarter.

Access to the mineralisation will be via a decline with a portal at the base of the Tropicana Open Pit. A second portal will be established later in the completed Boston Shaker Open pit (Figure 1). As disclosed in the Prefeasibility Study (PFS)1, underground conditions at Boston Shaker are good and conventional ground support systems and practices will be used for the underground development. The underground mine design is based on the use of conventional mechanised mining and underhand sublevel stoping.

The proposed mining fleet comprises: two jumbos, two production drills, three loaders (remote capable) and four trucks.

The Joint Venture has awarded the underground mining contract to Macmahon, a leading surface and underground mining services business. [03/28/2019, PR, p. 2, 4]

The processing plant, utilising conventional crushing, grinding and CIL (carbon-in-leach) recovery technology, was originally designed with a nameplate capacity of 5.8 million tonnes per annum and this was achieved in March 2014. In 2016 and 2017, an optimisation project increased the throughput capacity to 7.5 million tonnes per annum by the second half of FY17. In FY18, the Tropicana Joint Venture partners announced the construction of a second 6 megawatt ball mill. Installation and commissioning of the mill was completed on time and on budget in December 2018, increasing throughput capacity to 8.2 million tonnes per annum in FY19.

In March 2019, the Tropicana Joint Venture announced the commitment to the development of the Boston Shaker Underground mine following the successful completion of the Feasibility Study (FS). The FS assessed an underground operation with a mining rate of approximately 1.1Mtpa at estimated grades of 3.5g/t Au to produce approximately 100,000 oun ........