Underground Mining (hard Rock)
Underground hard rock mining refers to various underground mining techniques used to excavate hard minerals, mainly those containing metals such as ore containing gold, silver, iron, copper, zinc, nickel, tin and lead, but also involves using the same techniques for excavating ores of gems such as diamonds. In contrast soft rock mining refers to excavation of softer minerals such as salt, coal, or tar sands.
Read more about Underground Mining (hard Rock): Development Mining Vs. Production Mining, Ventilation, Ground Support, Ore Removal, Deepest Mines
Famous quotes containing the words underground and/or mining:
“Political correctness is driving machismo underground and recalling effeminacy from exile.”
—Mason Cooley (b. 1927)
“For every nineteenth-century middle-class family that protected its wife and child within the family circle, there was an Irish or a German girl scrubbing floors in that home, a Welsh boy mining coal to keep the home-baked goodies warm, a black girl doing the family laundry, a black mother and child picking cotton to be made into clothes for the family, and a Jewish or an Italian daughter in a sweatshop making “ladies” dresses or artificial flowers for the family to purchase.”
—Stephanie Coontz (20th century)