Types of mining and quarry operations include iron, copper, lead, zinc, gold, silver, uranium, coal, lignite, anthracite, oil & gas drilling and extraction, sand and gravel, granite, limestone, clay, potash, soda, borate, phosphate and other metallic and non-metallic minerals and fuels.
The quarry and aggregate, often referred to as sand and gravel, industry encompasses the process of obtaining stone, chalk, shale, etc., from its natural source, the earth and further processing it to a more useable form. This includes limestone, gravel, sand, etc., and is normally limited to surface, or open pit excavation, as opposed to underground mining. The actual excavation or obtaining the stone, or material being recovered, is essentially the same as open pit or surface mining for coal, copper and other earth minerals.
The equipment found in this industry includes both heavy construction mobile equipment, such as that found at a surface/strip mining operation or road construction job site, and plant production equipment, similar to that found in a cement mill. The most critical equipment found in the plant would include jaw, gyratory, cone, roll and/or hammermill crushers.
Surface mining is the predominant exploitation procedure worldwide, producing in the United States about 85% of all minerals, excluding petroleum and natural gas. Almost all metallic ores (98%), about 97% of the nonmetallic ores, and 61% of the coal in the United States are mined using surface methods (U.S. Geological Survey, 1995; Energy Information Administration, 2000 ), and most of these are mined by open pit or open cast methods.