The objective of underground mining is the extraction of ore below the surface. The underground methods employed are based on detailed drilling and sampling. Entry from the surface to an underground mine may be through an adit, a shaft, or a decline. The mining method employed needs to allow access to the ore while minimizing the amount of waste rock that needs to be removed to excavate the ore.

 

Underground mining is undertaken when the mineralization occurs below the surface and is confined to veins, fault zones or beds that tend to have a near-vertical planar or sheeted distribution that doesn’t accommodate open pit mining because the zone is too narrow and too much waste rock would have to be removed.