Mining is the extraction of valuable minerals
or other geological materials from the earth,
usually from an orebody, lode, vein, seam,
reef or placer deposit. These deposits form
a mineralized package that is of economic
interest to the miner.
Ores recovered by mining include metals, coal,
oil shale, gemstones, limestone, chalk, dimension
stone, rock salt, potash, gravel, and clay.
Mining is required to obtain any material
that cannot be grown through agricultural
processes, or created artificially in a laboratory
or factory. Mining in a wider sense includes
extraction of any non-renewable resource such
as petroleum, natural gas, or even water.
Mining of stones and metal has been a human
activity since pre-historic times. Modern
mining processes involve prospecting for ore
bodies, analysis of the profit potential of
a proposed mine, extraction of the desired
materials, and final reclamation of the land
after the mine is closed. De Re Metallica,
Georgius Agricola, 1550, Book I, Para. 1Mining
operations usually create a negative environmental
impact, both during the mining activity and
after the mine has closed. Hence, most of
the world's nations have passed regulations
to decrease the impact. Work safety has long
been a concern as well, and modern practices
have significantly improved safety in mines.
Levels of metals recycling are generally low.
Unless future end-of-life recycling rates
are stepped up, some rare metals may become
unavailable for use in a variety of consumer
products. Due to the low recycling rates,
some landfills now contain higher concentrations
of metal than mines themselves.
== History ==
=== 
Prehistoric mining ===
Since the beginning of civilization, people
have used stone, ceramics and, later, metals
found close to the Earth's surface. These
were used to make early tools and weapons;
for example, high quality flint found in northern
France, southern England and Poland was used
to create flint tools. Flint mines have been
found in chalk areas where seams of the stone
were followed underground by shafts and galleries.
The mines at Grimes Graves and Krzemionki
are especially famous, and like most other
flint mines, are Neolithic in origin (c. 4000–3000
BC). Other hard rocks mined or collected for
axes included the greenstone of the Langdale
axe industry based in the English Lake District.
The oldest-known mine on archaeological record
is the Ngwenya Mine in Swaziland, which radiocarbon
dating shows to be about 43,000 years old.
At this site Paleolithic humans mined hematite
to make the red pigment ochre. Mines of a
similar age in Hungary are believed to be
sites where Neanderthals may have mined flint
for weapons and tools.
=== Ancient Egypt ===
Ancient Egyptians mined malachite at Maadi.
At first, Egyptians used the bright green
malachite stones for ornamentations and pottery.
Later, between 2613 and 2494 BC, large building
projects required expeditions abroad to the
area of Wadi Maghareh in order to secure minerals
and other resources not available in Egypt
itself. Quarries for turquoise and copper
were also found at Wadi Hammamat, Tura, Aswan
and various other Nubian sites on the Sinai
Peninsula and at Timna.Mining in Egypt occurred
in the earliest dynasties. The gold mines
of Nubia were among the largest and most extensive
of any in Ancient Egypt. These mines are described
by the Greek author Diodorus Siculus, who
mentions fire-setting as one method used to
break down the hard rock holding the gold.
One of the complexes is shown in one of the
earliest known maps. The miners crushed the
ore and ground it to a fine powder before
washing the powder for the gold dust.
=== Ancient Greek and Roman mining ===
Mining in Europe has a very long history.
Examples include the silver mines of Laurium,
which helped support the Greek city state
of Athens. Although they had over 20,000 slaves
working them, their technology was essentially
identical to their Bronze Age predecessors.
At other mines, such as on the island of Thassos,
marble was quarried by the Parians after they
arrived in the 7th century BC. The marble
was shipped away and was later found by archaeologists
to have been used in buildings including the
tomb of Amphipolis. Philip II of Macedon,
the father of Alexander the Great, captured
the gold mines of Mount Pangeo in 357 BC to
fund his military campaigns. He also captured
gold mines in Thrace for minting coinage,
eventually producing 26 tons per year.
However, it was the Romans who developed large
scale mining methods, especially the use of
large volumes of water brought to the minehead
by numerous aqueducts. The water was used
for a variety of purposes, including removing
overburden and rock debris, called hydraulic
mining, as well as washing comminuted, or
crushed, ores and driving simple machinery.
The Romans 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. They built numerous aqueducts
to supply water to the minehead. There, the
water stored in large reservoirs and tanks.
When a full tank was opened, the flood of
water sluiced away the overburden to expose
the bedrock underneath and any gold veins.
The rock was then worked upon by fire-setting
to heat the rock, which would be quenched
with a stream of water. The resulting thermal
shock cracked the rock, enabling it to be
removed by further streams of water from the
overhead tanks. The Roman miners used similar
methods to work cassiterite deposits in Cornwall
and lead ore in the Pennines.
The methods had been developed by the Romans
in Spain in 25 AD to exploit large alluvial
gold deposits, the largest site being at Las
Medulas, where seven long aqueducts tapped
local rivers and sluiced the deposits. Spain
was one of the most important mining regions,
but all regions of the Roman Empire were exploited.
In Great Britain the natives had mined minerals
for millennia, but after the Roman conquest,
the scale of the operations increased dramatically,
as the Romans needed Britannia's resources,
especially gold, silver, tin, and lead.
Roman techniques were not limited to surface
mining. They followed the ore veins underground
once opencast mining was no longer feasible.
At Dolaucothi they stoped out the veins and
drove adits through bare rock to drain the
stopes. The same adits were also used to ventilate
the workings, especially important when fire-setting
was used. At other parts of the site, they
penetrated the water table and dewatered the
mines using several kinds of machines, especially
reverse overshot water-wheels. These were
used extensively in the copper mines at Rio
Tinto in Spain, where one sequence comprised
16 such wheels arranged in pairs, and lifting
water about 24 metres (79 ft). They were worked
as treadmills with miners standing on the
top slats. Many examples of such devices have
been found in old Roman mines and some examples
are now preserved in the British Museum and
the National Museum of Wales.
=== Medieval Europe ===
Mining as an industry underwent dramatic changes
in medieval Europe. The mining industry in
the early Middle Ages was mainly focused on
the extraction of copper and iron. Other precious
metals were also used, mainly for gilding
or coinage. Initially, many metals were obtained
through open-pit mining, and ore was primarily
extracted from shallow depths, rather than
through deep mine shafts. Around the 14th
century, the growing use of weapons, armour,
stirrups, and horseshoes greatly increased
the demand for iron. Medieval knights, for
example, were often laden with up to 100 pounds
(45 kg) of plate or chain link armour in addition
to swords, lances and other weapons. The overwhelming
dependency on iron for military purposes spurred
iron production and extraction processes.
The silver crisis of 1465 occurred when all
mines had reached depths at which the shafts
could no longer be pumped dry with the available
technology. Although an increased use of banknotes,
credit and copper coins during this period
did decrease the value of, and dependence
on, precious metals, gold and silver still
remained vital to the story of medieval mining.
Due to differences in the social structure
of society, the increasing extraction of mineral
deposits spread from central Europe to England
in the mid-sixteenth century. On the continent,
mineral deposits belonged to the crown, and
this regalian right was stoutly maintained.
But in England, royal mining rights were restricted
to gold and silver (of which England had virtually
no deposits) by a judicial decision of 1568
and a law in 1688. England had iron, zinc,
copper, lead, and tin ores. Landlords who
owned the base metals and coal under their
estates then had a strong inducement to extract
these metals or to lease the deposits and
collect royalties from mine operators. English,
German, and Dutch capital combined to finance
extraction and refining. Hundreds of German
technicians and skilled workers were brought
over; in 1642 a colony of 4,000 foreigners
was mining and smelting copper at Keswick
in the northwestern mountains.Use of water
power in the form of water mills was extensive.
The water mills were employed in crushing
ore, raising ore from shafts, and ventilating
galleries by powering giant bellows. Black
powder was first used in mining in Selmecbánya,
Kingdom of Hungary (now Banská Štiavnica,
Slovakia) in 1627. Black powder allowed blasting
of rock and earth to loosen and reveal ore
veins. Blasting was much faster than fire-setting
and allowed the mining of previously impenetrable
metals and ores. In 1762, the world's first
mining academy was established in the same
town there.
The widespread adoption of agricultural innovations
such as the iron plowshare, as well as the
growing use of metal as a building material,
was also a driving force in the tremendous
growth of the iron industry during this period.
Inventions like the arrastra were often used
by the Spanish to pulverize ore after being
mined. This device was powered by animals
and used the same principles used for grain
threshing.Much of the knowledge of medieval
mining techniques comes from books such as
Biringuccio’s De la pirotechnia and probably
most importantly from Georg Agricola's De
re metallica (1556). These books detail many
different mining methods used in German and
Saxon mines. A prime issue in medieval mines,
which Agricola explains in detail, was the
removal of water from mining shafts. As miners
dug deeper to access new veins, flooding became
a very real obstacle. The mining industry
became dramatically more efficient and prosperous
with the invention of mechanical and animal
driven pumps.
=== Classical Philippine civilization ===
Mining in the Philippines began around 1000
BC. The early Filipinos worked various mines
of gold, silver, copper and iron. Jewels,
gold ingots, chains, calombigas and earrings
were handed down from antiquity and inherited
from their ancestors. Gold dagger handles,
gold dishes, tooth plating, and huge gold
ornamets were also used. In Laszlo Legeza's
"Tantric elements in pre-Hispanic Philippines
Gold Art", he mentioned that gold jewelry
of Philippine origin was found in Ancient
Egypt. According to Antonio Pigafetta, the
people of Mindoro possessed great skill in
mixing gold with other metals and gave it
a natural and perfect appearance that could
deceive even the best of silversmiths. The
natives were also known for the jewelries
made of other precious stones such as carnelian,
agate and pearl. Some outstanding examples
of Philippine jewelry included necklaces,
belts, armlets and rings placed around the
waist.
=== The Americas ===
During prehistoric times, large amounts of
copper was mined along Lake Superior's Keweenaw
Peninsula and in nearby Isle Royale; metallic
copper was still present near the surface
in colonial times. Indigenous peoples used
Lake Superior copper from at least 5,000 years
ago; copper tools, arrowheads, and other artifacts
that were part of an extensive native trade
network have been discovered. In addition,
obsidian, flint, and other minerals were mined,
worked, and traded. Early French explorers
who encountered the sites made no use of the
metals due to the difficulties of transporting
them, but the copper was eventually traded
throughout the continent along major river
routes.
In the early colonial history of the Americas,
"native gold and silver was quickly expropriated
and sent back to Spain in fleets of gold-
and silver-laden galleons," the gold and silver
originating mostly from mines in Central and
South America. Turquoise dated at 700 AD was
mined in pre-Columbian America; in the Cerillos
Mining District in New Mexico, estimates are
that "about 15,000 tons of rock had been removed
from Mt. Chalchihuitl using stone tools before
1700."In 1727, Louis Denys (Denis) (1675–1741),
sieur de La Ronde – brother of Simon-Pierre
Denys de Bonaventure and the son-in-law of
René Chartier – took command of Fort La
Pointe at Chequamegon Bay; where natives informed
him of an island of copper. La Ronde obtained
permission from the French crown to operate
mines in 1733, becoming "the first practical
miner on Lake Superior"; seven years later,
mining was halted by an outbreak between Sioux
and Chippewa tribes.Mining in the United States
became prevalent in the 19th century, and
the General Mining Act of 1872 was passed
to encourage mining of federal lands. As with
the California Gold Rush in the mid-19th century,
mining for minerals and precious metals, along
with ranching, was a driving factor in the
Westward Expansion to the Pacific coast. With
the exploration of the West, mining camps
were established and "expressed a distinctive
spirit, an enduring legacy to the new nation;"
Gold Rushers would experience the same problems
as the Land Rushers of the transient West
that preceded them. Aided by railroads, many
traveled West for work opportunities in mining.
Western cities such as Denver and Sacramento
originated as mining towns.
When new areas were explored, it was usually
the gold (placer and then lode) and then silver
that were taken into possession and extracted
first. Other metals would often wait for railroads
or canals, as coarse gold dust and nuggets
do not require smelting and are easy to identify
and transport.
=== Modern period ===
In the early 20th century, the gold and silver
rush to the western United States also stimulated
mining for coal as well as base metals such
as copper, lead, and iron. Areas in modern
Montana, Utah, Arizona, and later Alaska became
predominate suppliers of copper to the world,
which was increasingly demanding copper for
electrical and households goods. Canada's
mining industry grew more slowly than did
the United States' due to limitations in transportation,
capital, and U.S. competition; Ontario was
the major producer of the early 20th century
with nickel, copper, and gold.Meanwhile, Australia
experienced the Australian gold rushes and
by the 1850s was producing 40% of the world's
gold, followed by the establishment of large
mines such as the Mount Morgan Mine, which
ran for nearly a hundred years, Broken Hill
ore deposit (one of the largest zinc-lead
ore deposits), and the iron ore mines at Iron
Knob. After declines in production, another
boom in mining occurred in the 1960s. Now,
in the early 21st century, Australia remains
a major world mineral producer.As the 21st
century begins, a globalized mining industry
of large multinational corporations has arisen.
Peak minerals and environmental impacts have
also become a concern. Different elements,
particularly rare earth minerals, have begun
to increase in demand as a result of new technologies.
== Mine development and lifecycle ==
The process of mining from discovery of an
ore body through extraction of minerals and
finally to returning the land to its natural
state consists of several distinct steps.
The first is discovery of the ore body, which
is carried out through prospecting or exploration
to find and then define the extent, location
and value of the ore body. This leads to a
mathematical resource estimation to estimate
the size and grade of the deposit.
This estimation is used to conduct a pre-feasibility
study to determine the theoretical economics
of the ore deposit. This identifies, early
on, whether further investment in estimation
and engineering studies is warranted and identifies
key risks and areas for further work. The
next step is to conduct a feasibility study
to evaluate the financial viability, the technical
and financial risks, and the robustness of
the project.
This is when the mining company makes the
decision whether to develop the mine or to
walk away from the project. This includes
mine planning to evaluate the economically
recoverable portion of the deposit, the metallurgy
and ore recoverability, marketability and
payability of the ore concentrates, engineering
concerns, milling and infrastructure costs,
finance and equity requirements, and an analysis
of the proposed mine from the initial excavation
all the way through to reclamation. The proportion
of a deposit that is economically recoverable
is dependent on the enrichment factor of the
ore in the area.
To gain access to the mineral deposit within
an area it is often necessary to mine through
or remove waste material which is not of immediate
interest to the miner. The total movement
of ore and waste constitutes the mining process.
Often more waste than ore is mined during
the life of a mine, depending on the nature
and location of the ore body. Waste removal
and placement is a major cost to the mining
operator, so a detailed characterization of
the waste material forms an essential part
of the geological exploration program for
a mining operation.
Once the analysis determines a given ore body
is worth recovering, development begins to
create access to the ore body. The mine buildings
and processing plants are built, and any necessary
equipment is obtained. The operation of the
mine to recover the ore begins and continues
as long as the company operating the mine
finds it economical to do so. Once all the
ore that the mine can produce profitably is
recovered, reclamation begins to make the
land used by the mine suitable for future
use.
== Mining techniques ==
Mining techniques can be divided into two
common excavation types: surface mining and
sub-surface (underground) mining. Today, surface
mining is much more common, and produces,
for example, 85% of minerals (excluding petroleum
and natural gas) in the United States, including
98% of metallic ores.Targets are divided into
two general categories of materials: placer
deposits, consisting of valuable minerals
contained within river gravels, beach sands,
and other unconsolidated materials; and lode
deposits, where valuable minerals are found
in veins, in layers, or in mineral grains
generally distributed throughout a mass of
actual rock. Both types of ore deposit, placer
or lode, are mined by both surface and underground
methods.
Some mining, including much of the rare earth
elements and uranium mining, is done by less-common
methods, such as in-situ leaching: this technique
involves digging neither at the surface nor
underground. The extraction of target minerals
by this technique requires that they be soluble,
e.g., potash, potassium chloride, sodium chloride,
sodium sulfate, which dissolve in water. Some
minerals, such as copper minerals and uranium
oxide, require acid or carbonate solutions
to dissolve.
=== Surface mining ===
Surface mining is done by removing (stripping)
surface vegetation, dirt, and, if necessary,
layers of bedrock in order to reach buried
ore deposits. Techniques of surface mining
include: open-pit mining, which is the recovery
of materials from an open pit in the ground,
quarrying, identical to open-pit mining except
that it refers to sand, stone and clay; strip
mining, which consists of stripping surface
layers off to reveal ore/seams underneath;
and mountaintop removal, commonly associated
with coal mining, which involves taking the
top of a mountain off to reach ore deposits
at depth. Most (but not all) placer deposits,
because of their shallowly buried nature,
are mined by surface methods. Finally, landfill
mining involves sites where landfills are
excavated and processed. Landfill mining has
been thought of as a solution to dealing with
long-term methane emissions and local pollution
=== 
Underground mining ===
Sub-surface mining consists of digging tunnels
or shafts into the earth to reach buried ore
deposits. Ore, for processing, and waste rock,
for disposal, are brought to the surface through
the tunnels and shafts. Sub-surface mining
can be classified by the type of access shafts
used, the extraction method or the technique
used to reach the mineral deposit. Drift mining
utilizes horizontal access tunnels, slope
mining uses diagonally sloping access shafts,
and shaft mining utilizes vertical access
shafts. Mining in hard and soft rock formations
require different techniques.
Other methods include shrinkage stope mining,
which is mining upward, creating a sloping
underground room, long wall mining, which
is grinding a long ore surface underground,
and room and pillar mining, which is removing
ore from rooms while leaving pillars in place
to support the roof of the room. Room and
pillar mining often leads to retreat mining,
in which supporting pillars are removed as
miners retreat, allowing the room to cave
in, thereby loosening more ore. Additional
sub-surface mining methods include hard rock
mining, which is mining of hard rock (igneous,
metamorphic or sedimentary) materials, bore
hole mining, drift and fill mining, long hole
slope mining, sub level caving, and block
caving.
=== Highwall mining ===
Highwall mining is another form of surface
mining that evolved from auger mining. In
Highwall mining, the coal seam is penetrated
by a continuous miner propelled by a hydraulic
Pushbeam Transfer Mechanism (PTM). A typical
cycle includes sumping (launch-pushing forward)
and shearing (raising and lowering the cutterhead
boom to cut the entire height of the coal
seam). As the coal recovery cycle continues,
the cutterhead is progressively launched into
the coal seam for 19.72 feet (6.01 m). Then,
the Pushbeam Transfer Mechanism (PTM) automatically
inserts a 19.72-foot (6.01 m) long rectangular
Pushbeam (Screw-Conveyor Segment) into the
center section of the machine between the
Powerhead and the cutterhead. The Pushbeam
system can penetrate nearly 1,000 feet (300
m) into the coal seam. One patented Highwall
mining system uses augers enclosed inside
the Pushbeam that prevent the mined coal from
being contaminated by rock debris during the
conveyance process. Using a video imaging
and/or a gamma ray sensor and/or other Geo-Radar
systems like a coal-rock interface detection
sensor (CID), the operator can see ahead projection
of the seam-rock interface and guide the continuous
miner's progress. Highwall mining can produce
thousands of tons of coal in contour-strip
operations with narrow benches, previously
mined areas, trench mine applications and
steep-dip seams with controlled water-inflow
pump system and/or a gas (inert) venting system.
== Machines ==
Heavy machinery is used in mining to explore
and develop sites, to remove and stockpile
overburden, to break and remove rocks of various
hardness and toughness, to process the ore,
and to carry out reclamation projects after
the mine is closed. Bulldozers, drills, explosives
and trucks are all necessary for excavating
the land. In the case of placer mining, unconsolidated
gravel, or alluvium, is fed into machinery
consisting of a hopper and a shaking screen
or trommel which frees the desired minerals
from the waste gravel. The minerals are then
concentrated using sluices or jigs.
Large drills are used to sink shafts, excavate
stopes, and obtain samples for analysis. Trams
are used to transport miners, minerals and
waste. Lifts carry miners into and out of
mines, and move rock and ore out, and machinery
in and out, of underground mines. Huge trucks,
shovels and cranes are employed in surface
mining to move large quantities of overburden
and ore. Processing plants utilize large crushers,
mills, reactors, roasters and other equipment
to consolidate the mineral-rich material and
extract the desired compounds and metals from
the ore.
== Processing ==
Once the mineral is extracted, it is often
then processed. The science of extractive
metallurgy is a specialized area in the science
of metallurgy that studies the extraction
of valuable metals from their ores, especially
through chemical or mechanical means.
Mineral processing (or mineral dressing) is
a specialized area in the science of metallurgy
that studies the mechanical means of crushing,
grinding, and washing that enable the separation
(extractive metallurgy) of valuable metals
or minerals from their gangue (waste material).
Processing of placer ore material consists
of gravity-dependent methods of separation,
such as sluice boxes. Only minor shaking or
washing may be necessary to disaggregate (unclump)
the sands or gravels before processing. Processing
of ore from a lode mine, whether it is a surface
or subsurface mine, requires that the rock
ore be crushed and pulverized before extraction
of the valuable minerals begins. After lode
ore is crushed, recovery of the valuable minerals
is done by one, or a combination of several,
mechanical and chemical techniques.
Since most metals are present in ores as oxides
or sulfides, the metal needs to be reduced
to its metallic form. This can be accomplished
through chemical means such as smelting or
through electrolytic reduction, as in the
case of aluminium. Geometallurgy combines
the geologic sciences with extractive metallurgy
and mining.
In 2018, led by Chemistry and Biochemistry
professor Bradley D. Smith, University of
Notre Dame researchers "invented a new class
of molecules whose shape and size enable them
to capture and contain precious metal ions,"
reported in a study published by the Journal
of the American Chemical Society. The new
method "converts gold-containing ore into
chloroauric acid and extracts it using an
industrial solvent. The container molecules
are able to selectively separate the gold
from the solvent without the use of water
stripping." The newly developed molecules
can eliminate water stripping, whereas mining
traditionally "relies on a 125-year-old method
that treats gold-containing ore with large
quantities of poisonous sodium cyanide...
this new process has a milder environmental
impact and that, besides gold, it can be used
for capturing other metals such as platinum
and palladium," and could also be used in
urban mining processes that remove precious
metals from wastewater streams.
== Environmental effects ==
Environmental issues can include erosion,
formation of sinkholes, loss of biodiversity,
and contamination of soil, groundwater and
surface water by chemicals from mining processes.
In some cases, additional forest logging is
done in the vicinity of mines to create space
for the storage of the created debris and
soil. Contamination resulting from leakage
of chemicals can also affect the health of
the local population if not properly controlled.
Extreme examples of pollution from mining
activities include coal fires, which can last
for years or even decades, producing massive
amounts of environmental damage.
Mining companies in most countries are required
to follow stringent environmental and rehabilitation
codes in order to minimize environmental impact
and avoid impacting human health. These codes
and regulations all require the common steps
of environmental impact assessment, development
of environmental management plans, mine closure
planning (which must be done before the start
of mining operations), and environmental monitoring
during operation and after closure. However,
in some areas, particularly in the developing
world, government regulations may not be well
enforced.
For major mining companies and any company
seeking international financing, there are
a number of other mechanisms to enforce good
environmental standards. These generally relate
to financing standards such as the Equator
Principles, IFC environmental standards, and
criteria for Socially responsible investing.
Mining companies have used this oversight
from the financial sector to argue for some
level of industry self-regulation. In 1992,
a Draft Code of Conduct for Transnational
Corporations was proposed at the Rio Earth
Summit by the UN Centre for Transnational
Corporations (UNCTC), but the Business Council
for Sustainable Development (BCSD) together
with the International Chamber of Commerce
(ICC) argued successfully for self-regulation
instead.This was followed by the Global Mining
Initiative which was begun by nine of the
largest metals and mining companies and which
led to the formation of the International
Council on Mining and Metals, whose purpose
was to "act as a catalyst" in an effort to
improve social and environmental performance
in the mining and metals industry internationally.
The mining industry has provided funding to
various conservation groups, some of which
have been working with conservation agendas
that are at odds with an emerging acceptance
of the rights of indigenous people – particularly
the right to make land-use decisions.Certification
of mines with good practices occurs through
the International Organization for Standardization
(ISO). For example, ISO 9000 and ISO 14001,
which certify an "auditable environmental
management system", involve short inspections,
although they have been accused of lacking
rigor. Certification is also available through
Ceres' Global Reporting Initiative, but these
reports are voluntary and unverified. Miscellaneous
other certification programs exist for various
projects, typically through nonprofit groups.The
purpose of a 2012 EPS PEAKS paper was to provide
evidence on policies managing ecological costs
and maximise socio-economic benefits of mining
using host country regulatory initiatives.
It found existing literature suggesting donors
encourage developing countries to:
Make the environment-poverty link and introduce
cutting-edge wealth measures and natural capital
accounts.
Reform old taxes in line with more recent
financial innovation, engage directly with
the companies, enacting land use and impact
assessments, and incorporate specialised support
and standards agencies.
Set in play transparency and community participation
initiatives using the wealth accrued.
=== Waste ===
Ore mills generate large amounts of waste,
called tailings. For example, 99 tons of waste
are generated per ton of copper, with even
higher ratios in gold mining – because only
5.3 g of gold is extracted per ton of ore,
a ton of gold produces 200,000 tons of tailings.
(As time goes on and richer deposits are exhausted
– and technology improves to permit – this
number is going down to .5 g and less.) These
tailings can be toxic. Tailings, which are
usually produced as a slurry, are most commonly
dumped into ponds made from naturally existing
valleys. These ponds are secured by impoundments
(dams or embankment dams). In 2000 it was
estimated that 3,500 tailings impoundments
existed, and that every year, 2 to 5 major
failures and 35 minor failures occurred; for
example, in the Marcopper mining disaster
at least 2 million tons of tailings were released
into a local river. In central Finland, Talvivaara
Terrafame polymetal mine waste effluent since
2008 and numerous leaks of saline mine water
has resulted in ecological collapse of nearby
lake. Subaqueous tailings disposal is another
option. The mining industry has argued that
submarine tailings disposal (STD), which disposes
of tailings in the sea, is ideal because it
avoids the risks of tailings ponds; although
the practice is illegal in the United States
and Canada, it is used in the developing world.The
waste is classified as either sterile or mineralised,
with acid generating potential, and the movement
and storage of this material forms a major
part of the mine planning process. When the
mineralised package is determined by an economic
cut-off, the near-grade mineralised waste
is usually dumped separately with view to
later treatment should market conditions change
and it becomes economically viable. Civil
engineering design parameters are used in
the design of the waste dumps, and special
conditions apply to high-rainfall areas and
to seismically active areas. Waste dump designs
must meet all regulatory requirements of the
country in whose jurisdiction the mine is
located. It is also common practice to rehabilitate
dumps to an internationally acceptable standard,
which in some cases means that higher standards
than the local regulatory standard are applied.
=== Renewable energy and mining ===
Many mining sites are remote and not connected
to the grid. Electricity is typically generated
with diesel generators. Due to high transportation
cost and theft during transportation the cost
for generating electricity is normally high.
Renewable energy applications are becoming
an alternative or amendment. Both solar and
wind power plants can contribute in saving
diesel costs at mining sites. Renewable energy
applications have been built at mining sites.
Cost savings can reach up to 70%.
== Mining industry ==
Mining exists in many countries. London is
known as the capital of global "mining houses"
such as Rio Tinto Group, BHP Billiton, and
Anglo American PLC. The US mining industry
is also large, but it is dominated by the
coal and other nonmetal minerals (e.g., rock
and sand), and various regulations have worked
to reduce the significance of mining in the
United States. In 2007 the total market capitalization
of mining companies was reported at US$962
billion, which compares to a total global
market cap of publicly traded companies of
about US$50 trillion in 2007. In 2002, Chile
and Peru were reportedly the major mining
countries of South America. The mineral industry
of Africa includes the mining of various minerals;
it produces relatively little of the industrial
metals copper, lead, and zinc, but according
to one estimate has as a percent of world
reserves 40% of gold, 60% of cobalt, and 90%
of the world's platinum group metals. Mining
in India is a significant part of that country's
economy. In the developed world, mining in
Australia, with BHP Billiton founded and headquartered
in the country, and mining in Canada are particularly
significant. For rare earth minerals mining,
China reportedly controlled 95% of production
in 2013.
While exploration and mining can be conducted
by individual entrepreneurs or small businesses,
most modern-day mines are large enterprises
requiring large amounts of capital to establish.
Consequently, the mining sector of the industry
is dominated by large, often multinational,
companies, most of them publicly listed. It
can be argued that what is referred to as
the 'mining industry' is actually two sectors,
one specializing in exploration for new resources
and the other in mining those resources. The
exploration sector is typically made up of
individuals and small mineral resource companies,
called "juniors", which are dependent on venture
capital. The mining sector is made up of large
multinational companies that are sustained
by production from their mining operations.
Various other industries such as equipment
manufacture, environmental testing, and metallurgy
analysis rely on, and support, the mining
industry throughout the world. Canadian stock
exchanges have a particular focus on mining
companies, particularly junior exploration
companies through Toronto's TSX Venture Exchange;
Canadian companies raise capital on these
exchanges and then invest the money in exploration
globally. Some have argued that below juniors
there exists a substantial sector of illegitimate
companies primarily focused on manipulating
stock prices.Mining operations can be grouped
into five major categories in terms of their
respective resources. These are oil and gas
extraction, coal mining, metal ore mining,
nonmetallic mineral mining and quarrying,
and mining support activities. Of all of these
categories, oil and gas extraction remains
one of the largest in terms of its global
economic importance. Prospecting potential
mining sites, a vital area of concern for
the mining industry, is now done using sophisticated
new technologies such as seismic prospecting
and remote-sensing satellites. Mining is heavily
affected by the prices of the commodity minerals,
which are often volatile. The 2000s commodities
boom ("commodities supercycle") increased
the prices of commodities, driving aggressive
mining. In addition, the price of gold increased
dramatically in the 2000s, which increased
gold mining; for example, one study found
that conversion of forest in the Amazon increased
six-fold from the period 2003–2006 (292
ha/yr) to the period 2006–2009 (1,915 ha/yr),
largely due to artisanal mining.
=== Corporate classifications ===
Mining companies can be classified based on
their size and financial capabilities:
Major companies are considered to have an
adjusted annual mining-related revenue of
more than US$500 million, with the financial
capability to develop a major mine on its
own.
Intermediate companies have at least $50 million
in annual revenue but less than $500 million.
Junior companies rely on equity financing
as their principal means of funding exploration.
Juniors are mainly pure exploration companies,
but may also produce minimally, and do not
have a revenue exceeding US$50 million.
=== Regulation and governance ===
New regulations and a process of legislative
reforms aim to improve the harmonization and
stability of the mining sector in mineral-rich
countries. New legislation for mining industry
in African countries still appears to be an
issue, but has the potential to be solved,
when a consensus is reached on the best approach.
By the beginning of the 21st century the booming
and increasingly complex mining sector in
mineral-rich countries was providing only
slight benefits to local communities, especially
in given the sustainability issues. Increasing
debate and influence by NGOs and local communities
called for a new approahes which would also
include disadvantaged communities, and work
towards sustainable development even after
mine closure (including transparency and revenue
management). By the early 2000s, community
development issues and resettlements became
mainstream concerns in World Bank mining projects.
Mining-industry expansion after mineral prices
increased in 2003 and also potential fiscal
revenues in those countries created an omission
in the other economic sectors in terms of
finances and development. Furthermore, this
highlighted regional and local demand for
mining revenues and an inability of sub-national
governments to effectively use the revenues.
The Fraser Institute (a Canadian think tank)
has highlighted the environmental protection
laws in developing countries, as well as voluntary
efforts by mining companies to improve their
environmental impact.In 2007 the Extractive
Industries Transparency Initiative (EITI)
was mainstreamed in all countries cooperating
with the World Bank in mining industry reform.
The EITI operates and was implemented with
the support of the EITI multi-donor trust
fund, managed by the World Bank. The EITI
aims to increase transparency in transactions
between governments and companies in extractive
industries by monitoring the revenues and
benefits between industries and recipient
governments. The entrance process is voluntary
for each country and is monitored by multiple
stakeholders including governments, private
companies and civil society representatives,
responsible for disclosure and dissemination
of the reconciliation report; however, the
competitive disadvantage of company-by company
public report is for some of the businesses
in Ghana at least, the main constraint. Therefore,
the outcome assessment in terms of failure
or success of the new EITI regulation does
not only "rest on the government's shoulders"
but also on civil society and companies.On
the other hand, implementation has issues;
inclusion or exclusion of artisanal mining
and small-scale mining (ASM) from the EITI
and how to deal with "non-cash" payments made
by companies to subnational governments. Furthermore,
the disproportionate revenues the mining industry
can bring to the comparatively small number
of people that it employs, causes other problems,
like a lack of investment in other less lucrative
sectors, leading to swings in government revenuebecause
of volatility in the oil markets. Artisanal
mining is clearly an issue in EITI Countries
such as the Central African Republic, D.R.
Congo, Guinea, Liberia and Sierra Leone – i.e.
almost half of the mining countries implementing
the EITI. Among other things, limited scope
of the EITI involving disparity in terms of
knowledge of the industry and negotiation
skills, thus far flexibility of the policy
(e.g. liberty of the countries to expand beyond
the minimum requirements and adapt it to their
needs), creates another risk of unsuccessful
implementation. Public awareness increase,
where government should act as a bridge between
public and initiative for a successful outcome
of the policy is an important element to be
considered.
=== World Bank ===
The World Bank has been involved in mining
since 1955, mainly through grants from its
International Bank for Reconstruction and
Development, with the Bank's Multilateral
Investment Guarantee Agency offering political
risk insurance. Between 1955 and 1990 it provided
about $2 billion to fifty mining projects,
broadly categorized as reform and rehabilitation,
greenfield mine construction, mineral processing,
technical assistance, and engineering. These
projects have been criticized, particularly
the Ferro Carajas project of Brazil, begun
in 1981. The World Bank established mining
codes intended to increase foreign investment;
in 1988 it solicited feedback from 45 mining
companies on how to increase their involvement.In
1992 the World Bank began to push for privatization
of government-owned mining companies with
a new set of codes, beginning with its report
The Strategy for African Mining. In 1997,
Latin America's largest miner Companhia Vale
do Rio Doce (CVRD) was privatized. These and
other developments such as the Philippines
1995 Mining Act led the bank to publish a
third report (Assistance for Minerals Sector
Development and Reform in Member Countries)
which endorsed mandatory environment impact
assessments and attention to the concerns
of the local population. The codes based on
this report are influential in the legislation
of developing nations. The new codes are intended
to encourage development through tax holidays,
zero custom duties, reduced income taxes,
and related measures. The results of these
codes were analyzed by a group from the University
of Quebec, which concluded that the codes
promote foreign investment but "fall very
short of permitting sustainable development".
The observed negative correlation between
natural resources and economic development
is known as the resource curse.
== Safety ==
Safety has long been a concern in the mining
business, especially in sub-surface mining.
The Courrières mine disaster, Europe's worst
mining accident, involved the death of 1,099
miners in Northern France on March 10, 1906.
This disaster was surpassed only by the Benxihu
Colliery accident in China on April 26, 1942,
which killed 1,549 miners. While mining today
is substantially safer than it was in previous
decades, mining accidents still occur. Government
figures indicate that 5,000 Chinese miners
die in accidents each year, while other reports
have suggested a figure as high as 20,000.
Mining accidents continue worldwide, including
accidents causing dozens of fatalities at
a time such as the 2007 Ulyanovskaya Mine
disaster in Russia, the 2009 Heilongjiang
mine explosion in China, and the 2010 Upper
Big Branch Mine disaster in the United States.
Mining has been identified by the National
Institute for Occupational Safety and Health
(NIOSH) as a priority industry sector in the
National Occupational Research Agenda (NORA)
to identify and provide intervention strategies
regarding occupational health and safety issues.
The Mining Safety and Health Administration
(MSHA) was established in 1978 to "work to
prevent death, illness, and injury from mining
and promote safe and healthful workplaces
for US miners." Since its implementation in
1978, the number of miner fatalities has decreased
from 242 miners in 1978 to 28 miners in 2015.
There are numerous occupational hazards associated
with mining, including exposure to rockdust
which can lead to diseases such as silicosis,
asbestosis, and pneumoconiosis. Gases in the
mine can lead to asphyxiation and could also
be ignited. Mining equipment can generate
considerable noise, putting workers at risk
for hearing loss. Cave-ins, rock falls, and
exposure to excess heat are also known hazards.
The current NIOSH Recommended Exposure Limit
(REL) of noise is 85 dBA with a 3 dBA exchange
rate and the MSHA Permissible Exposure Limit
(PEL) is 90 dBA with a 5 dBA exchange rate
as an 8-hour time-weighted average. NIOSH
has found that 25% of noise-exposed workers
in Mining, Quarrying, and Oil and Gas Extraction
have hearing impairment. The prevalence of
hearing loss increased by 1% from 1991-2001
within these workers.
Noise studies have been conducted in several
mining environments. Stageloaders (84-102
dBA), shearers (85-99 dBA), auxiliary fans
(84-120 dBA), continuous mining machines (78-109
dBA), and roof bolters (92-103 dBA) represent
some of the noisiest equipment in underground
coal mines. Dragline oilers, dozer operators,
and welders using air arcing were occupations
with the highest noise exposures among surface
coal miners. Coal mines had the highest hearing
loss injury likelihood.Proper ventilation,
hearing protection, and spraying equipment
with water are important safety practices
in mines.
== Records ==
As of 2008, the deepest mine in the world
is TauTona in Carletonville, South Africa,
at 3.9 kilometres (2.4 mi), replacing the
neighboring Savuka Mine in the North West
Province of South Africa at 3,774 metres (12,382
ft). East Rand Mine in Boksburg, South Africa
briefly held the record at 3,585 metres (11,762
ft), and the first mine declared the deepest
in the world was also TauTona when it was
at 3,581 metres (11,749 ft).
The Moab Khutsong gold mine in North West
Province (South Africa) has the world's longest
winding steel wire rope, which is able to
lower workers to 3,054 metres (10,020 ft)
in one uninterrupted four-minute journey.The
deepest mine in Europe is the 16th shaft of
the uranium mines in Příbram, Czech Republic,
at 1,838 metres (6,030 ft), second is Bergwerk
Saar in Saarland, Germany, at 1,750 metres
(5,740 ft).
The deepest open-pit mine in the world is
Bingham Canyon Mine in Bingham Canyon, Utah,
United States, at over 1,200 metres (3,900
ft). The largest and second deepest open-pit
copper mine in the world is Chuquicamata in
northern Chile at 900 metres (3,000 ft), which
annually produces 443,000 tons of copper and
20,000 tons of molybdenum.The deepest open-pit
mine with respect to sea level is Tagebau
Hambach in Germany, where the base of the
pit is 293 metres (961 ft) below sea level.
The largest underground mine is Kiirunavaara
Mine in Kiruna, Sweden. With 450 kilometres
(280 mi) of roads, 40 million tonnes of annually
produced ore, and a depth of 1,270 metres
(4,170 ft), it is also one of the most modern
underground mines. The deepest borehole in
the world is Kola Superdeep Borehole at {{convert|12262|m|ft},
but this is connected to scientific drilling,
not mining.
== Metal reserves and recycling ==
During the 20th century, the variety of metals
used in society grew rapidly. Today, the development
of major nations such as China and India and
advances in technologies are fueling an ever-greater
demand. The result is that metal mining activities
are expanding and more and more of the world’s
metal stocks are above ground in use rather
than below ground as unused reserves. An example
is the in-use stock of copper. Between 1932
and 1999, copper in use in the US rose from
73 kilograms (161 lb) to 238 kilograms (525
lb) per person.95% of the energy used to make
aluminium from bauxite ore is saved by using
recycled material. However, levels of metals
recycling are generally low. In 2010, the
International Resource Panel, hosted by the
United Nations Environment Programme (UNEP),
published reports on metal stocks that exist
within society and their recycling rates.The
report's authors observed that the metal stocks
in society can serve as huge mines above ground.
However, they warned that the recycling rates
of some rare metals used in applications such
as mobile phones, battery packs for hybrid
cars, and fuel cells are so low that unless
future end-of-life recycling rates are dramatically
stepped up these critical metals will become
unavailable for use in modern technology.
As recycling rates are low and so much metal
has already been extracted, some landfills
now contain a higher concentrations of metal
than mines themselves. This is especially
true of aluminium, used in cans, and precious
metals, found in discarded electronics. Furthermore,
waste after 15 years has still not broken
down, so less processing would be required
when compared to mining ores. A study undertaken
by Cranfield University has found £360 million
of metals could be mined from just 4 landfill
sites. There is also up to 20MJ/kg of energy
in waste, potentially making the re-extraction
more profitable. However, although the first
landfill mine opened in Tel Aviv, Israel in
1953, little work has followed due to the
abundance of accessible ores.
== See also
