Underground mining (hard rock) - Wikipedia
Underground hard rock mining refers to various underground mining techniques used to excavate hard minerals, usually 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 or rubies. Soft rock mining refers to excavation of softer minerals such as salt, coal,Hammer Mills - Mt Baker Mining and Metals,Hammer Mills. Mt. Baker Mining and Metals designs and builds hammer mills with longevity in mind. These units feature wire feed welds, and replaceable-wear parts. Each machine comes complete and ready to run, including hammer mill, inlet chute, belts, motor, fullOffice of Wastewater Management - Hardrock Mining,,Mining and benefication operations greatly increase the rate of these same chemical reactions by removing sulfide rock material and exposing the material to air and water. Characteristics Acid generation primarily results from the oxidation of metallic sulfides.