Mining generally is the extraction of
valuable minerals or other geological materials from the earth, usually from an
ore body, vein or (coal) seam. Materials recovered by mining include base
metals, precious metals, iron, coal, diamonds, limestone, oil shale, raw salt
and potash. Any material that cannot be grown through agricultural processes,
or created artificially in a laboratory or factory is usually mined. Mining in
a wider sense comprises extraction of any non-renewable resource (eg.
Petroleum, natural gas, or even water).
Quarry
mining and metal have been done since prehistoric times. Modern mining
processes involve prospecting for ore bodies, analysis of the profit potential
of a proposed mine, extraction of the desired materials and finally reclamation
of the land to prepare it for other uses
once the mine is closed. The nature of mining processes creates a potential
negative impact on the environment both during the mining operations and for
years after the mine is closed (West 1970; Lankton 1991; Vaden and provost
2000; Heiss and Oeggl 2008). This impact has led to most of the world’s nations
adopting regulations to moderate the negative
effects of mining operations for safety .
Since
the beginning of civilization people have used stone, ceramics and later metals
found on or close to the earth’s surface to manufacture early tools and
weapons, for instance, high quality flint found in Northern France and southern
England were used to create flint tools (Hartman, 1992). The oldest known mine
on archaeological record is the “Lion” Cave” in Swaziland, which by
radiocarbon, date about 43,000 years , of which Paleolithic humans mined mineral
hematite, which contained iron and was grinded to produce the red pigment Ochre
(Swaziland Natural Trust Commission, 2007). Mines of a similar age in Hungary
are believed to be sites where Neanderthals may have mined flint for weapons
and tools .Ancient Egyptians mined malachite at Maadi (Shaw, 2000).
Mining
in Europe has a very long pedigree, example including the silver mines of
laurium, which helped support the Greek city state of Athens. However Romans
developed large scale mining methods, especially the use of large volumes of
water brought to the mine head by
numerous aqueducts ( Wilsdorf, 1970) . The water was used for a variety of
purposes, including using it to remove overburden and rock debris, called
hydraulic mining as well as washing crushed ores, and driving simple machinery.
They used hydraulic mining methods on a large scale to prospect for the veins
of ore, especially a now obsolete form of mining known as hushing. It involved
building numerous aqueducts to supply water to
the mine head where it was stored in large reservoirs and tanks. When a
full tank was opened, the wave of water sluiced away the overburden to expose
the bedrock underneath and any gold veins. The rock was then attacked by
fire-setting to heat the rock which would be quenched with a stream of water.
The thermal shock cracked the rock, enabling it to be removed, aided by further
streams of water from the overhead tanks. They used similar methods to work
cassiterite deposits in Cornwall and lead ore in the peinnines. The methods
had been developed by the Romans in 25
AD to exploit large alluvial gold deposits, the largest site being at Las
Meduas, where seven long aqueducts were built to tap local rivers and to sluice
the deposits. Mining in the Medieval period is best known through the work of
De Re Metallica in 1556 of George Agricola, who described many different mining
methods then used in German and Saxon mines ( Agricola, 1556).