A. The Structure of the Open-Pit Mine
An open-pit mine is structured in steps, often also termed “benches,” which are the pit’s vertical levels. These steps commonly range from four to sixty meters, but the size is largely dependent upon the machinery used by the mining company. The walls of the pit are called the batter, while the flat portion is called the berm or the bench.
Open-pit walls will generally be dug in a manner that minimizes any danger of rock falls or landslides in the event of poor weather conditions such as heavy rain. However, there may also be supports such as rock bolts or shotcrete used to stabilize the area for workers. In addition, many open-pit mines require water relief measures to be put in place. In some instances, bore holes may be drilled into the wall, which can also cause wall failures.
B. Hauling Rocks and Minerals from an Open-Pit Mine
All mines have to have a way to haul out the ore that is mined. Most open-pit mines have a roadbuilt at the pit’s side specifically for hauling away the ore, as well as any waste rock. This roadallows trucks to move safely beside the mining area and obtain their respective loads.
The waste is also an issue that has to be dealt with accordingly in any mining situation. In mostcases, waste rock will be placed in a waste dump, often an area close to the pit’s edge that is alsostepped in structure.
C. What is Left Behind by Open-Pit Mines?
Tailings are a telltale sign of a former mining operation. Tailings are the leftovers of ore that was processed and, if fresh, it is often found in slurry form in a settling pond or what is called a tailings dam. The water eventually evaporates...