Mucking

Once the rock or the ore has been broken by by explosives it is called muck;what we know as the muck pile is the pile of broken ore. This ore has to be loaded into either rail cars or trucks to be transported to an ore pass for further transfer to the surface. The loading procedure is called mucking. A very big variety of of haulers and loaders is available to mining companies.

The load-haul-dump (LHD) machine is probably the most common mucking machine. These machines with rubber tires vary in size from very small, compact units with buckets that can manage 14 cubic feet (0.4 cubic metres) of muck to the much larger units which are equipped with 212-cubic-foot (6-cubic-metre) buckets or larger. load-haul-dump machines can be powered by diesel engines or by electric motors. In mines where haulage distances are very big, load-haul-dump machines are used to load rail cars or haulage trucks, which then haul the rock (or ore) to the surface via a ramp, or to an ore pass, a vertical working the ore can be dumped down – like garbage or laundry down a chute. The ore goes to an underground crusher or is hoisted to the surface from the ore pass.

Continuous mucking machines lift the muck from the floor directly on to a conveyor belt which afterwards loads it into a truck or on to another conveyor. High-speed electric trolley trucks also have the ability of being used to bring the ore to the surface. Conveyor belts are also finding more applications in underground mines for transporting ore to an ore pass or crusher. Such large-volume mucking systems are most of the time restricted to mines that use bulk mining methods in the thousands-of-tonnes-per-day ranges.

Backfilling
Once a stope has been mined out, it is usually necessary to backfill it with some waste material so that the ore which is adjacent to the stope can be mined without affecting the structural integrity of the underground workings. Backfill can be waste rock from underground, sand brought down from the surface, or mill tailings that have been processed so that all the fine fraction has been removed. This material is most of the time mixed with a bonding agent like cement so that it stands up once the ore adjacent to it is mined out. Backfill can be placed immediately during the mining cycle, or it can also be placed once the stope is entirely mined out.