The Widgiemooltha mineralisation is controlled by north-northwest trending structures and mainly hosted within basaltic rocks. Alteration assemblages consist of biotite-albite-carbonate and contain finely disseminated sulphides, mostly pyrite. The veining is dominantly quartz-carbonate with minor pyrite. Small aplite dykes, 1 m to 10 m thick, occur at Bass and Hronsky, and minor cherty-pyritic sediments and pegmatitic dykes at Flinders.

Two ore morphologies can be identified at North Widgiemooltha, namely the steeply-dipping tabular lodes such as Bass and Hronsky, and the stacked shallow-dipping reef complexes hosting Flinders, Darlek and to a lesser extent West Oliver.

There is only thin transported overburden in local areas (<3 m). The degree of weathering in the area varies with saprolite (100% weathered sulphides) from 0 to 15 m below the surface, while saprock (a mixture of weathered and unweathered sulphides) occurs down to 50 m depth.

Mine designs included geotechnical imports from Green Geotechnical who reviewed existing pits in the immediate area and fresh diamond drill core. There were recommendations of a series of wall and batter angles for pit designs; the steepest angle was 70°.

Pit designs assume open pit mining using six-wheel articulated trucks that haul on steeper ramps and have a small turning radius.

Mining dilution is factored at 20% for all pits, except the main Flinders pit which was assigned 10% given the greater ore widths. Mining recovery is 95% for all the prospects. A minimum mining width of 2.0 m was adopted. These parameters are considered appropriate by independent consultants for the types of mineralisation observed at Widgiemooltha.

Standard CIP recovery from cyanide leached gold is the recovery method.