2. Open-pit mining, also known as open-cast or
open-cut mining and in larger contexts mega-mining
Surface mining, including strip mining, open-pit mining and mountaintop
removal mining, is a broad category of mining in which soil and rock overlying
the mineral deposit (the overburden) are removed, in contrast to underground
mining, in which the overlying rock is left in place, and the mineral is removed
through shafts or tunnels.
In most forms of surface mining, heavy equipment, such as earthmovers, first
remove the overburden. Next, large machines, such as dragline excavators or
bucket-wheel excavators, extract the mineral.
Advantages of surface mining include lower cost and greater safety
compared to underground mining.
Disadvantages include hazards to human health and the environment.
Humans face a variety of health risks caused by mining such as different
cardiovascular diseases, food, and water contamination. Habitat
destruction, alongside air, noise, and water pollution, are all significant negative
environmental impacts caused by the side effects of surface mining.
3.
4.
5.
6.
7.
8.
9.
10. The Bagger 288 is a bucket-wheel excavator used in strip
Strip mining is the practice of mining a seam of mineral, by first
removing a long strip of overlying soil and rock as overburden
removal. It is most commonly used to mine coal and lignite (brown
coal). Strip mining is only practical when the ore body to be
excavated is relatively near the surface and/or is mostly
horizontal. The more common method is area stripping, which is
used on fairly flat terrain, to extract deposits over a large area. As
each long strip is excavated, the overburden is placed in the
excavation produced by the previous strip.
11. Strip mining at Garzweiler surface mine in Germany. The lignite being extracted is at left, the removed overburden being
placed at right. Note that it is a largely flat mine for a horizontal mineral.
Contour mining involves removing the overburden above the mineral seam near an outcrop in hilly
terrain, where the mineral outcrop usually follows the contour of the land. Contour stripping is often
followed by auger mining into the hillside, to remove more of the mineral. This method commonly
leaves behind terraces in mountainsides.
12. Open-pit mining refers to a method of extracting rock or minerals from the earth through their removal
from an open pit or borrow. This process is done on the ground surface of the earth. It is best suited for
accessing mostly vertical deposits of minerals. Although open-pit mining is sometimes mistakenly referred
to as "strip mining", the two methods are different.
Open pit mining vs Open cast Mining
Open pit mining the deposit shape is
mostly parallel to the surface while in
open cast mining ,the deposit shape is
bedded and tabular.
Open cast mining involves the backfilling
of waste in the mind out open cast
excavations or stopes during the mining
process while open pit mining mostly
involves the backfilling at the end of the
mining life as part of mine reclamation
process.
13. Mountaintop removal mining (MTR), also known as
mountaintop mining (MTM), is a form of surface
mining at the summit or summit ridge of a mountain.
Coal seams are extracted from a mountain by removing
the land, or overburden, above the seams. This process
is considered to be safer compared to underground
mining because the coal seams are accessed from
above instead of underground. In the United States,
this method of coal mining is conducted in the
Appalachian Mountains in the eastern United States.
Explosives are used to remove up to 400 vertical feet
(120 m) of mountain to expose underlying coal seams.
Excess rock and soil is dumped into nearby valleys, in
what are called "holler fills" ("hollow fills") or "valley
fills".
14. Mountaintop removal mining (MTR), also known as mountaintop mining (MTM)
Mountaintop removal mining (MTR), also known as mountaintop mining (MTM)
15. Placer mining
A gold dredge is a placer mining machine
that extracts gold from sand, gravel, and
dirt using water and mechanical
methods.The original gold dredges were
large, multi-story machines built in the
first half of the 1900s.
Small suction machines are currently
marketed as "gold dredges" to individuals
seeking gold: just offshore from the beach
of Nome, Alaska, for instance.
16. Rock blasting at the large
open-pit Twin Creeks gold
mine in Nevada, United
States. Note the size of the
excavators for scale
(foreground, left), and that
the bottom of the mine is
not visible.
17. Open-pit mines that produce building materials and dimension stone
are commonly referred to as “quarries.”
Marble quarry in Tuscany, Italy.
18. Portland stone quarry, Isle of Portland, Dorset, England
Limestone is quarried for aggregate and other uses,
Tennessee, U.S.
Quarry, place where dimension stone or aggregate (sand,
gravel, crushed rock) is mined. The products of dimension
stone quarries are prismatic blocks of rock such as
marble, granite, limestone, sandstone, and slate. After
cutting and polishing, these materials are used in the
primary construction of buildings and monuments and
also for decorative facing materials applied to the exterior
and interior of buildings.
Dimension stones are extracted in a highly selective
manner, using time-consuming and expensive methods for
freeing the blocks from the surrounding rock.
