The El Chino Mine located near [[Silver City, New Mexico is an open-pit copper mine]]
Mining is the extraction of
valuable minerals or other geological materials from the earth, usually (but not always) from an
ore body, vein, or (coal) seam. Materials commonly recovered by mining include
bauxite,
coal,
copper,
diamonds,
iron,
gold,
lead,
manganese,
magnesium,
nickel,
phosphate,
platinum,
salt,
silver,
tin,
titanium,
uranium, and
zinc. Other highly useful materials that are mined include
clay,
sand, cinder,
gravel, granite, and
limestone. Any material that cannot be grown from agricultural processes must be mined. Mining in a wider sense can also include extraction of
petroleum and
natural gas.
History
The oldest known mine in the archaeological record is the "Lion Cave" in
Swaziland. At this site, which has a radiocarbon age of 43,000 years,
paleolithic humans mined for the
iron-containing mineral
hematite, which they presumably ground to produce the red
pigment ochre.
Sites of a similar age where Neandertals may have mined
flint for weapons and tools have been found in
Hungary.
Another early mining operation was 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 (60 m) in depth and 300 feet (90 m) in width was removed with stone tools; the mine dump covers 20 acres (81,000 m²).
Mining techniques
Mining techniques can be divided into two basic
excavation types:
1.
Surface mining
:
:
:
:
:
2. Sub-surface mining
:
:
:
:
The science of
extractive metallurgy is the study of beneficiation and extraction of valuable metals and minerals from their ores. Although extractive metallurgy is all encompassing,
mineral processing or mineral dressing is often the term used for the study of processing coal, industrial minerals and precious stones, as these are not metals.
Environmental effects
Iron hydroxide precipitate stains a stream receiving acid drainage from surface coal mining.
Several million dollars annually are spent on the environmental effects of these [[tailing ponds at
Climax, Colorado, even though the
molybdenum mine has been closed for decades.]]
Mining can have devastating effects. The result can be unnaturally high concentrations of some chemical elements over a significantly wider area of surface. Combined with the effects of water and the new
channels created for water to travel through, collect in, and contact with these chemicals, a situation is created where mass-scale contamination can occur.
Some examples of environmental problems associated with mining operations are:
:'''Tar Creek''', an abandoned mining area in
Picher, Oklahoma that is now an
Environmental Protection Agency superfund site. Water in the mine has leaked through into local
groundwater, contaminating it with metals such as
lead and
cadmium.
http://www.health.state.ok.us/PROGRAM/envhlth/sites/ottawa.html
:'''Scouriotissa''', a copper mine in
Cyprus that has been abandoned. Contaminated dust blows off this site.
:'''
Berkeley Lake', an abandoned pit mine in
Butte, Montana that has filled with water which is now acidic and poisonous.
Although such issues have been associated with some mining operations in the past, modern mining practices have improved significantly and are subject to close environmental scrutiny. Problems remain especially in countries with lax environmental regulations or enforcement.
Mining Industry
While exploration and mining can sometimes be conducted by individual entrepreneurs or small business, most modern-day mines are large enterprises requiring large amounts of capital to establish. Consequently, the industry is dominated by large, often multinational, mostly publicly-listed companies. See :Category:Mining companies for a list.
See also
References
Category:Environment
Category:Mining
bg:Минно дело
ca:Mineria
de:Bergbau
es:Minería
eo:Minado
fr:Mine (matériaux)
nl:Mijnbouw
no:Gruvedrift
ja:鉱業
pl:Górnictwo
pt:Mineração
sv:Gruva