Transcript Mineral resource

Geology and
Nonrenewable Mineral
Resources


The earth is made up of a core, mantle, and crust
and is constantly changing as a result of processes
taking place on and below its surface.
The earth’s interior consists of:
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Core: innermost zone with solid inner core and molten
outer core that is extremely hot.
Mantle: solid rock with a rigid outer part
(asthenosphere) that is melted pliable rock.
Crust: Outermost zone which underlies the continents.
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Major features of the earth’s crust and upper
mantle.
Figure 15-2
Spreading
center
Collision between
two continents
Subduction
zone
Continental
crust
Oceanic
crust
Ocean
trench
Oceanic
crust
Continental
crust
Material cools Cold dense
as it reaches material falls
the outer back through
mantle
mantle
Hot
Mantle
material
convection
rising
cell
through
the
mantle
Two plates move
towards each other.
One is subducted
back into the mantle
on a falling convection
current.
Mantle
Hot outer
core Inner
core
Fig. 15-3, p. 337
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Huge volumes of heated and molten rack
moving around the earth’s interior form
massive solid plates that move extremely
slowly across the earth’s surface.
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Tectonic plates: huge rigid plates that are moved
with convection cells or currents by floating on
magma or molten rock.
Figure 15-4
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The extremely slow movements of these plates
cause them to grind into one another at
convergent plate boundaries, move apart at
divergent plate boundaries and slide past at
transform plate boundaries.
Figure 15-4
Fig. 15-4, p. 338

The San Andreas
Fault is an
example of a
transform fault.
Figure 15-5
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Weathering is
an external
process that
wears the
earth’s surface
down.
Figure 15-6
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The earth’s crust consists of solid inorganic
elements and compounds called minerals that can
sometimes be used as resources.
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Mineral resource: is a concentration of naturally
occurring material in or on the earth’s crust that can be
extracted and processed into useful materials at an
affordable cost.
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The U.S. Geological Survey classifies mineral
resources into four major categories:
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Identified: known location, quantity, and quality or
existence known based on direct evidence and
measurements.
Undiscovered: potential supplies that are assumed to
exist.
Reserves: identified resources that can be extracted
profitably.
Other: undiscovered or identified resources not
classified as reserves
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Examples are fossil
fuels (coal, oil),
metallic minerals
(copper, iron), and
nonmetallic
minerals (sand,
gravel).
Figure 15-7
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Deposits of nonrenewable mineral resources in
the earth’s crust vary in their abundance and
distribution.
A very slow chemical cycle recycles three types
of rock found in the earth’s crust:
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Sedimentary rock (sandstone, limestone).
Metamorphic rock (slate, marble, quartzite).
Igneous rock (granite, pumice, basalt).
Erosion
Transportation
Weathering
Deposition
Igneous rock
Granite,
pumice,
basalt
Sedimentary
rock
Sandstone,
limestone
Heat, pressure
Cooling
Heat, pressure,
stress
Magma
(molten rock)
Melting
Metamorphic rock
Slate, marble,
gneiss, quartzite
Fig. 15-8, p. 343

The extraction, processing, and use of mineral
resources has a large environmental impact.
Figure 15-9
Natural Capital Degradation
Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources
Steps
Environmental effects
Mining
Disturbed land; mining
accidents; health hazards,
mine waste dumping, oil
spills and blowouts; noise;
ugliness; heat
Exploration,
extraction
Processing
Use
Solid wastes; radioactive
material; air, water, and
soil pollution; noise;
safety and health
hazards; ugliness; heat
Transportation or
transmission to
individual user,
eventual use, and
discarding
Noise; ugliness; thermal
water pollution; pollution
of air, water, and soil;
solid and radioactive
wastes; safety and health
hazards; heat
Transportation,
purification,
manufacturing
Fig. 15-10, p. 344
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A variety of methods are used based on mineral
depth.
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Surface mining: shallow deposits are removed.
 Remove overburden
 Discard as waste material (spoils)
 Examples:
 Open-pit mining, area strip mining, contour strip mining,
mountain-top removal
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Subsurface mining: deep deposits are removed.
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Machines dig
holes and remove
ores, sand, gravel,
and stone.
Toxic
groundwater can
accumulate at the
bottom.
Figure 15-11
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Earth movers strips
away overburden, and
giant shovels removes
mineral deposit.
Often leaves highly
erodible hills of rubble
called spoil banks.
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Succession slow after
mining – no topsoil
Desertification in arid
areas
Figure 15-12
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Used on hilly or
mountainous
terrain.
Unless the land is
restored, a wall of
dirt is left in front
of a highly
erodible bank
called a highwall.
Figure 15-13
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Machinery removes the
tops of mountains to
expose coal.
Resulting waste rock
and dirt are dumped
into the streams and
valleys below.
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Causes flood hazards
Leaches toxic metals into
waterways
Increasing in WV and KY
Figure 15-14
before
Larry Gibson on the
issue
after
A positive view
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Scarring and
disruption of the land
surface
Subsidence
Toxin laced mining
wastes
Air pollution
Acid deposition from
smelting gases
Figure 15-15
The future supply of a resource depends on its affordable
supply and how rapidly that supply is used.
Never completely run out
Economic depletion – costs
more to find, extract,
transport, and process the
remaining deposit than it is
worth.
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Options:
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Recycle/reuse
Waste less
Use less
Find a substitute
Do without
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A rising price for a scarce
mineral resource can
increase supplies and
encourage more efficient use.
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Depletion curves
for a renewable
resource using
three sets of
assumptions.
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Dashed vertical lines
represent times
when 80% depletion
occurs.
Figure 15-16
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Mining no longer a free market
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New technologies can increase the mining of low-grade
ores at affordable prices, but harmful environmental effects
can limit this approach.
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Subsidized for depletion
Consumer pays via taxes
Biomining – slow, but environmentally less destructive
Ocean mineral resources
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Cost too much to extract
Squabbles over who owns them (i.e. deposits in international waters)
Environmental effects are poorly understood
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Seawater
Continental shelf
deposits
Hydrothermal vent
deposits
Manganese nodules
Figure 15-17
Solutions
Sustainable Use of Nonrenewable Minerals
• Do not waste mineral resources.
• Recycle and reuse 60–80% of mineral resources.
• Include the harmful environmental costs of
mining and processing minerals in the prices
of items (full-cost pricing).
• Reduce subsidies for mining mineral resources.
• Increase subsidies for recycling, reuse, and
finding less environmentally harmful substitutes.
• Redesign manufacturing processes to use less
mineral resources and to produce less pollution
and waste.
• Have the mineral-based wastes of one
manufacturing process become the raw
materials for other processes.
• Sell services instead of things.
• Slow population growth.
Fig. 15-18, p. 351
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Growing signs point to an ecoindustrial revolution
taking place over the next 50 years.
The goal is to redesign industrial manufacturing
processes to mimic how nature deals with wastes.
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Industries can interact in complex resource exchange
webs in which wastes from manufacturer become raw
materials for another.
Figure 15-19