Underground mining (soft rock) refers to a group of underground mining techniques used to extract coal, oil shale and other minerals or geological materials from sedimentary ("soft") rocks. Because deposits in sedimentary rocks are commonly layered and relatively less hard, the mining methods used differ from those used to mine deposits in igneous or metamorphic rocks (see Underground mining (hard rock)). Underground mining techniques also differ greatly from those of surface mining.
Read more about Underground Mining (soft Rock): Methods
Famous quotes containing the words underground and/or mining:
“It is in our interests to let the police and their employers go on believing that the Underground is a conspiracy, because it increases their paranoia and their inability to deal with what is really happening. As long as they look for ringleaders and documents they will miss their mark, which is that proportion of every personality which belongs in the Underground.”
—Germaine Greer (b. 1939)
“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)