The proposed mining method within MTW is the same as that currently employed. Large electric face shovels, hydraulic excavators and front-end loaders are utilised to load haul trucks to remove pre-strip and parting material. Draglines are used to expose lowest coal seams. Ancillary equipment in the form of drills, graders, rubber-tyred dozers and water carts will provide the mining equipment with support as required. Coal is extracted by front-end loaders and/or excavators loading haul trucks.
The current mining equipment will continue to be used. In general, changes may occur due to replacement or as technology changes.
Overburden and Interburden Material
Overburden removal at MTW is centred on shovel pre-stripping methods and dragline “stripping”. Multiple bench pre-stripping is used to expose shallower coal seams with a combination of dragline and shovel operations to remove lower interburden. Overburden removal operations generally proceed as follows:
- Tree clearing and timber harvesting is carried out under contract. Topsoil removal is carried out under contract using small earthmoving equipment such as a D6 bulldozer with a loader and trucks.
- Overburden is drilled. Generally holes stop short of the coal seams to reduce blast damage to vthe coal. Hole diameters range from 200mm to 270mm. Drill patterns depend on hole depth and hole diameter but pattern sizes will generally range from 5m x 6m to 10m x 12m.
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