There are two basic types of extraction: surface and sub-surface
(deep), each relying on a variety of techniques. Regardless of
process, U.S. legislation requires operators to submit a plan
for restoring the land and mitigating acid mine drainage before
a permit is granted for mining operations. It further specifies
that all sites be restored to their original contours and
provides a funding mechanism for helping restore abandoned
mines. When minerals are located deep within the ground, there
are a variety of underground mining methods that can be utilized
for excavation. The method is based primarily on whether the
mineral is soft rock (i.e., coal) or hard rock (often those
containing hard metals like copper or lead), and is often site
specific ? taking geologic, economic, and safety factors into
consideration. In hard rock mining, blasting occurs in order to
unearth the waste rock, separating it from the mineral deposit.
Ventilation is a priority in order to dissipate any toxic fumes
from blasting and other