The Edna May deposit is located within the Westonia Greenstone Belt, within the Southern Cross Province of Western Australia’s Archaean Yilgarn Craton.

Mineralisation is hosted by the east-west striking, north dipping, Edna May Gneiss (EMG), which has a currently defined strike length of 1km, width of 140m and drilled depth extent of 700m. The EMG is a tonalitic quartz-feldspar-biotite gneiss interpreted to be a strongly metamorphosed granitic intrusion. Mafic-ultramafic amphibolites form the hangingwall and footwall units.

Gold mineralisation is widespread within the EMG and related to two quartz vein sets. One set comprises of widespread, thin, sheeted veins in a ladder of stockwork style, generally sub- parallel to stratigraphy. The second set are less frequent, larger veins which cross-cut the EMG and have much greater continuity. These veins formed the basis of the historical underground ‘reefs’ and the two significant lodes defined in the early 2018 underground infill drilling programme.

These lodes have typical dimensions of 2-5m thickness, strike lengths of 80-110m and currently drilled dip extents of 200m. Associated visible gold is commonly seen in drill core.

Mining operations at Edna May focused on the Edna May underground mine, Greenfinch open pit, and the recently developed Marda Gold Project (Python, Dugite, Dolly Pot, Goldstream open pits in the Marda Central area).

Edna May lode (UG deposit) is modelled with consideration of extraction by conventional sub-level open stoping methods (open stoping underground method).

Mining contractor:
RUC Cementation Mining
- Full underground services including all decline and lateral development
- Production including long hole open stoping, blasting, bogging and backfilling of stopes with CRF. The level interval varies from 16 to 20m (floor to floor) to limit up dip stope length to 18m. Cemented rock fill sill pillars is emplaced at mid-levels to divide the mine design into two top down stope sequences
- Predominately new equipment fleet including new Sandvik Jumbo DD421, CAT 2900, CAT 1700K. Longhole drilling DL421.

The Edna May orebody is open at depth with high grade intersections seen down to 600 metres below surface. Open pit mining is by conventional drill and blast, load and haul method. A bulk mining approach has been adopted to the extraction of remnant high grade reef structures and associated stockwork mineralisation. This allows the mine to employ a single mining fleet for most of the mine life. The open pit is being mined in two stages and is carried out on 10.5 metre benches and 3.5 metre flitches.

Blended ore is processed through 2 stage crushing circuit. Crushed ore is stored on a coarse ore stockpile with a live capacity of approximately 3,800 tonnes. The grinding circuit consists of a primary SAG mill, secondary ball mill crushing circuit.

Primary crushing/grinding plant/machinery:

Mobile crushing fleet including jaw crusher, cone crusher, vibrating screen and 2 x stacker conveyors. 70t and 20t cranes.

Grinding plant equipment:
SAG with 2,000kW installed power, SAG mill size 6.71m x 2.59m, rubber-steel composite liners, Ball mill with 3,720kW installed power, ball mill size 5.03m x 8.21m, composite. Classification WarmanCavex 400mm (400CVX).

Screening plant/equipment:
Trash screen horizontal vibratory 2.4m x 6.1m, polyurethane deck 0.8mm cross flow slots.

Recycle crusher:
Terex RC45 cone crusher, vibrating feeder bypass using an overflow bin. Nominal reduction CCS of 14mm.

The Edna May mill is a 2.9 million tonne per annum (Mtpa) conventional CIL gold plant. Mill feed is now being sourced from the new underground, the nearby Greenfinch open pit, complemented by stockpiled ore and the Marda open pit project.

Mineral recovery plant/equipment:
Knelson concentrator XD 40, followed by Consep Acacia Reactor 3 type CS 1000DM. CIP leach circuit with 2 x 2,000m tanks and 6 x 3 1,100m adsorption tanks. Elution circuit - pressure Zadra. 3 x electrowinning tanks, 2 in parallel for leach circuit and 1 for gravity circuit.

Refining plant/equipment:
8t elution column, 8t acid wash column.