Mining at Dugald River is planned to be underground with the long-hole open stoping method favoured. Currently the deposit is accessed by two declines.
The orebody access is split into a north and south mine, due to its 2 km strike length and a low-grade zone at the extremities of the orebody.
The north mine is narrow (average ~5 m true width) and sub-vertical. The south mine is wider than the north mine with a flexural zone in the centre. The south mine is narrow and steep in the upper zone (~top 200 m from surface) and lower zone (~below 700 m from surface). The central zone is flatter and thicker than the upper and lower zones.
Mining methods for the mine are Sub-Level Open Stopes (SLOS) both Longitudinal and Transverse in the South Mine and modified Avoca stoping or Core & Shell stopes with rib pillars in the North Mine. Level intervals occur every 25m and stopes have a strike length of 15m.
The stopes are broken into the following categories:
- Longitudinal SLOS, for stopes upto 10-15m wide horizontally. (Where the orebody has thickened adjacent stopes are mined in sequence after paste filling);
- Transverse SLOS, for stopes where the orebody thickness lends itself to sequential stope extraction retreating along cross-cuts;
- Crown pillar SLOS, for the top level of each panel where stoping occurs directly below a previously mined area;
- Modified Avoca stopes/Core & Shell Stopes for the North Mine.