Damang gold mine - Mining
Conventional drill and blast with truck and shovel mining techniques are employed at all open pits. Load-and-haul is carried out by 90 tonne dump trucks and 14 to 20 tonne excavators in backhoe and face shovel configurations. Mining benches are blasted in 9m benches and excavated in 3m flitches. Gold mineralisation is mined selectively to cut-off grades, and segregated into grade ranges to balance the ore production and processing capacities on-site and to maximise cash-flow.
Off-highway trucks haul the ore to the ROM pad and waste to the respective planned dumps. For pits that are further from the ROM Pad, the off-highway trucks haul the ore to interim stockpiles near the pits and a fleet of 30 to 40 tonne trucks reclaim and transport the ore to the RoM Pad.
Damang has a progressive reclamation plan, where areas that become inactive are immediately rehabilitated through contouring and placement of topsoil, seeding, planting and fertilisation.
Mine planning and scheduling
Open pit optimisation software, in conjunction with economic parameters and physical constraints, is used to generate a series of nested pits for open pit mining. An optimal shell is then selected and a detailed design used to confirm the mineability.
Mine planning is based on 3D block models of in situ mineralisation, with allowances made for minimum mining widths, dilution and ore loss in line with the mining method being considered. Historical performance measures are considered in determining these modifying factors.
Infrastructure, tailings storage facilities, waste disposal and ore stockpile management requirements are incorporated into the planning process.
Electronic detonators will be reintroduced in 2018 for blasting in the Damang pit, together with existing blast movement monitoring. A pre-split wall control method is being implemented along all the pit walls in the fresh zones to ensure the stability of the pit walls.