The mining of alluvial deposits and, later, lode or vein deposits required crushing prior to gold extraction, and this consumed immense amounts of manpower.
(The mining of ocean deposits lies in the future).
For the mining of beach deposits above sea level, conventional surface techniques are sufficient.
Placer mining of such deposits yields magnetite, cassiterite, and zircon and gold, platinum, and other rare metals.
The separation, identification and assessment of high-grade ore zones from low-grade ones are extremely important in mining of metalliferous deposits.
During this time, some of the reef's islands were mined for deposits of guano, and lighthouses were built as beacons throughout the system.
The presence of water suggests that the crater floor could potentially be "mined" for deposits of hydrogen in water form, a commodity that is expensive to deliver directly from the Earth.
Last year, the oil sands — thick, heavy oil called bitumen that is mixed in with sand and clay — produced about 1.5 million barrels of oil a day, half from strip mining of relatively shallow deposits, the other from injecting steam into wells in deeper reserves.
Instead of seeing deep sea drilling and the mining of vast mineral deposits on the ocean floors as a creative challenge to mankind and a way of improving our well-being in ways we can't fully anticipate, significant elements of our society want to stop all drilling.
Presently, the mining of these chromite deposits is carried out on small scale by the local miners.
