Mining

Common materials extracted are:

bauxite (for aluminum)

coal,

copper,

diamonds,

iron (from the ores haematite and limonite),

gold,

nickel,

salt,

silver,

tin,

uranium.

Techniques include:

• Hard rock mining
• Open pit mining
• Quarrying
• Strip mining
• Tunnel mining[?]
• Placer mining[?], which was important in the recovery of alluvial deposits of gold and continues to be used in the mining of gems in Myanamar[?] and Sri Lanka

Bioleaching is the application of naturally available bacteria to extract metals from their ore.

The first mining operation on Earth may have been the turquoise mine operated by the ancient Egyptians at Wady Maghareh on the Sinai Peninsula. Turquoise was also mined in pre-Columbian America in the Cerillos Mining District in New Mexico where a mass of rock 200 feet in depth and 300 feet in width was removed with stone tools; the mine dump covers 20 acres.

Further reading

• Hardrock Gold: A Miner's Tale, Tom Morrison, illustrated by Cherry Hunter, University of Oklahoma Press, 1992, hardcover, ISBN 0806124423