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Mining
• Is used to extract valuable
minerals from the earth
• Is dependent on crustal
abundance
• Elements and minerals are not
equally represented or
distributed in the earth’s crust
• Countries and companies
have mineral reserves
• Known quantity that can be
realistically recovered by
mining
Relative crustal abundance
of most common minerals
Mined Materials
• Sand and gravel
• Metals
• Phosphates
• Salts
• Sodium
• Sulfur
• Gemstones
• Fuel sources
• Coal
• Uranium
Ore
• Concentrated accumulations of
minerals formed from geologic
processes
• Can also contain waste material
• Must usually be processed to produce
a pure form of the mineral
• Can occur in veins
• Localized high concentrations of a
mineral
• Can occur in disseminated deposits
• Large, widely spread lower
concentrations of a mineral
Types of Mining
• Surface Mining
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Placer
Strip
Mountaintop Removal
Open Pit
• Subsurface Mining
• Shaft
• Solution*
• Ocean Mining*
Placer Mining
• Used when a resource
accumulates in riverbed deposits
• Running water is used to sift
lighter materials from the
heavier resource materials
• Also called panning
• Disturbs large amounts of
sediment
Strip Mining
• Used when a resource exists in
layers near the Earth’s surface
• Rock and soil above the resource
(overburden) is removed from a
strip of land
• Mined material is removed and
overburden is replaced
Mountaintop Mining
• Used when a resource
occurs in seams near
mountain ridges
• Entire mountaintops are
bulldozed and blasted
away to reveal the seam
• Overburden is replaced
on the remaining
mountain, and may fall
or be dumped into
adjacent valleys
Open Pit Mining
• Used when a resource is in an area unsuitable for
tunneling, or when it is spread evenly and close to the
surface
• Called a quarry
Subsurface Mining
• Used when a resource
occurs deep
underground
• Vertical shafts are dug
into the ground
• Horizontal tunnels are
dug to follow the seam
or deposit being mined
• Material is removed and
sent to the surface for
processing
Solution Mining*
• Also called in-situ
recovery
• Used when a resource is
buried deep, and can be
dissolved in liquid
• A hole is drilled to the
resource, and water or
acid is poured into the
hole
• The resource is sucked
out and processed to
remove it from the fluid
Ocean Mining*
• Used when resource deposits
exist on or under the sea floor,
or in seawater
• Resources are “vacuumed” off
the sea floor
• Research is underway to extract
or evaporate resources from
seawater
Problems with Mining
• All mining uses machinery and
transportation that produces
pollution
• All mining produces tailings, or
mineral waste that can damage
ecosystems
• The processing of ore can produce
toxic byproducts
• Miners are exposed to some of the
most hazardous working conditions
on the planet
Acid Drainage*
• Most harmful form of
environmental damage from
mining
• Occurs when newly exposed
rock that contain sulfur reacts
with water and oxygen to form
sulfuric acid
Acid Drainage*
• Sulfuric acid leaches
metals from nearby
rock and soil
• Forms toxic acidic
liquid called leachate
• Cleanup involves
neutralizing the acid
and removing the
metals
Brownfields*
• Abandoned sites polluted with
hazardous waste
• Includes abandoned mines
• Dangerous and difficult to clean
up for reuse
• Fall under EPA Superfund sites
Mine Restoration or Reclamation
• Goal is to restore a mined site
to as close to its original
condition as possible
• Involves:
• Filling in shafts and holes
• Removing mining structures and
equipment
• Replacing overburden
• Replanting
• Ecosystems never fully recover
from mining disruption
General Mining Act of 1872
• Any individual or company can
stake an exclusive claim on federal
land open for mining
• Land can be patented, or bought
outright, for about $5/acre
• No payments are made to the
government, even if profits are
realized
• Includes gemstones, metals,
uranium and minerals
Mineral Leasing Act of 1920*
• Public lands must be leased for
mining, and royalties on profits
are to be paid
• Amounts depend on the
resource being mined
• Covers fossil fuels, sodium,
sulfur, and phosphates
Surface Mining Control and Reclamation Act
of 1977
• Regulates the surface effects of
coal mining
• Mandates reclamation of mined
areas
Minerals are Nonrenewable*
• Minerals regenerate
slowly
• Many mineral deposits
are being mined very
quickly
• As they become scarce,
they will become more
expensive
• Environmentally friendly
alternatives are being
sought, including
recycling
Sustainable Mineral Use*
• Recycling is the best way
to sustainably use many
minerals
• Uses less energy in
production of goods
• Reduces the amount of
mining
• Recycling e-waste is
especially important
• Reducing the use of
products that contain
minerals also helps