The Braidwood Granodiorite and adjacent Long Flat Volcanics host the primary gold mineralisation in the Dargues Reef–Majors Creek area.

Three major mineralisation styles are present: auriferous, pyrite-rich greisenous zones such as those at Dargues Reef, Exeter Farm and Scotsmans Gully; gold–base metal-rich veins/lodes, including those adjacent to the Majors Creek village; and those deposits which have both greisen- and vein-type mineralisation, including those in the Snobs mine area, which takes in Snobs Reef (Snobs Lode–Stewart & Mertons–United Miners zone) and The Creek prospect.

Mineralisation at Dargues occurs as a number of discrete, fracture-controlled sulphide lodes situated within intense zones of phyllic alteration (silica-chlorite and lesser epidote and sericite). The lodes are steeply dipping (80 - 90 degrees) and have a variable strike from E-W to ENE-WSW. The main zones of mineralisation (commonly referred to as the Big Blow and Main Lode) occur on the northern side of a parallel diorite dyke with some minor mineralisation sporadically developed on the southern margin. The mineralisation and dyke are synonymous with the dominant fault orientations of the region, an E-W striking vertical set and a ENE-WSW set, dipping steeply to the SSE.

The sulphide lodes are generally 0.5 m to 10 m wide (true width) and up to 200 m long and display a distinctive zonal alteration assemblage. The lodes are generally comprised of potassium felspar ........

Ore is mined using conventional bottom-up longhole stoping and trucked from the underground mine to a surface stockpile adjacent to the process plant. Stope voids are backfilled with cemented hydraulic fill or waste rock. Mine access is via a boxcut and decline from the surface.

Mine Design and Assumptions
Detailed stope design has been completed for the LOM Plan with these shapes used preferentially. Mining dilution and recovery estimates for the various stoping types were applied, based on the stoping method. These include remnant stoping (30% mining dilution, 70% recovery), longitudinal stoping (20% mining dilution, 95% recovery), transverse stoping (10% mining dilution, 95% recovery) and narrow stoping (25% mining dilution, 95% recovery).

In addition, the geology model was assessed by creating stope shapes using Deswik’s SO software. Parameters included 0.5m hangingwall and footwall dilution allowances, with stope strike length of 20m and a minimum mining width of 2m. These shapes are used where new drilling and modelling updates weren’t captured by the LOM planning process. Mining dilution and recovery factors applied to these shapes includes downhole stopes (2% mining dilution with 95% recovery), uphole stopes (2% mining dilution with 90% recovery), and sill pillar mining (10% mining dilution with 85% recovery).

Development designs have 15% mining dilution applied with 100% recovery.

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