The Fortnum deposits are Paleoproterozoic shear-hosted gold deposits within the Fortnum Wedge, a localised thrust duplex of Narracoota Formation within the overlying Ravelstone Formation. Both stratigraphic formations comprise part of the Bryah Basin in the Capricorn Orogen, Western Australia.

The Horseshoe Cassidy deposits are hosted within the Ravelstone Formation (siltstone and argillite) and Narracoota Formation (highly-altered, moderate to strongly deformed mafic to ultramafic rocks). The main zone of mineralisation is developed within a horizon of highly altered magnesian basalt. Gold mineralisation is associated with strong vein stockworks that are confined to the altered mafic. Alteration consists of two types: stockwork proximal silica-carbonate-fuchsite-haematite-pyrite and distal silicahaematite-carbonate+/- chlorite.

The Peak Hill district represents remnants of a Proterozoic fold belt comprising highly deformed trough and shelf sediments and mafic / ultramafic volcanics, which are generally moderately metamorphosed (except for the Peak Hill Metamorphic Suite).

The Starlight ore system is mined underground and has a number of lodes varying in strike and width from 5-150m and 1-40m respectively. The wider zones resulting from the bulking of lodes.

The Yarlarweelor mineral resource extends over 1,400m in strike length, 570m in lateral extent and 190m in depth.

The Tom’s and Sam’s mineral resource extends over 650m in strike length, 400m in lateral extent and 130m in depth.

The Eldorado mineral resource extends over 240m in strike length, 100m in lateral extent and 100m in depth.

Mining output is currently dominated by the Starlight underground mine with supplementary, free on surface low grade stocks providing a blended feedstock to the plant.

FGO continues to deliver strong profit from the Starlight underground mine and additional mill feed sourced from large, existing low-grade surface stockpiles. This year saw expanded production in the Starlight mine including the Moonlight, Twilight North and Trev’s lodes.

In-mine exploration at FGO is focussed on the potential extension of the Starlight orebodies to ensure longevity of the low-cost, high productivity mining model that is the cornerstone of the FGO project. In addition, Westgold is evaluating potential open pit opportunities to supplement underground ore sources at FGO increasing the ore optionality and mine life across this underexplored tenement package.

Underground
In large disseminated orebodies sub level caving, sub level open stoping or single level bench stoping production methodologies are used. In narrow vein laminated quartz hosted domains a conservative narrow bench style mining method is used. In narrow flat dipping deposits a Flat Long Hole process is adopted (with fillets in the footwall for rill angle) and or jumbo stoping. Minimum mining widths have been applied in the various mining methods.

The FGO (Fortnum Gold Operations) processing hub incorporates the 0.9 Mtpa Fortnum carbon-in-leach (CIL) processing plant.

The process plant performed well given the hard ore and limited grind capacity, achieving more than 1,260,000 tonnes for the year with metallurgical recoveries at 95%. In FY22 open pit mining will recommence to replace the existing low-grade ore stocks in the mill feed and enhance overall ore grade sent to the FGO processing plant.

The Processing Plant at FGP consists of a single stage Primary Crusher, a SAG mill, Ball mill and Pebble Crusher followed by three leach and 5 adsorption tanks with a gold recovery/elution circuit.