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Chapter 16
Geology and
Nonrenewable Mineral
Resources
GEOLOGIC PROCESSES

The earth is constantly
changing as a result of
processes taking place on and
below its surface.
 The earth’s interior consists of:



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.
Volcanoes
Abyssal hills
Oceanic crust
(lithosphere)
Abyssal Oceanic
floor
ridge
Abyssal
floor
Trench
Folded
mountain
belt
Abyssal plain
Craton
Continental
shelf
Continental
slope
Continental
rise
Continental crust (lithosphere)
Mantle (lithosphere)
Fig. 15-2, p. 336
GEOLOGIC PROCESSES
 Huge
volumes of heated and molten rock
moving around the earth’s interior form
massive solid plates that move extremely
slowly across the earth’s surface.

Tectonic plates: huge rigid plates that are
moved with convection cells or currents by
floating on magma or molten rock.
The Earth’s Major Tectonic Plates
Figure 15-4
The Earth’s Major Tectonic Plates
 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
Trench
Volcanic island arc
Craton
Transform
fault
Lithosphere
Asthenosphere
Divergent plate boundaries
Lithosphere
Rising
magma
Asthenosphere
Convergent plate boundaries
Lithosphere
Asthenosphere
Transform faults
Fig. 15-4b, p. 338
GEOLOGIC PROCESSES
 The
San
Andreas Fault is
an example of a
transform fault.
Figure 15-5
Wearing Down and Building Up the
Earth’s Surface
 Weathering
is
an external
process that
wears the
earth’s
surface
down.
Figure 15-6
Parent material
(rock)
Biological
weathering
(tree roots and
lichens)
Chemical
weathering
(water, acids,
and gases)
Particles of parent material
Physical weathering
(wind, rain, thermal
expansion and
contraction, water
freezing)
Fig. 15-6, p. 340
What Are Resources?
• An available supply that can be drawn
upon as needed.
– Hardin “Tragedy of the Commons”
– Conservation – management/regulation of a
resource so that it does not exceed the
capacity to regenerate itself.
• Natural Resources – Ecosystems (biotic
and abiotic) – in terms of ecosystem or
“natural” capital.
Renewable vs. Nonrenewable
• Renewable – Sun, plants, animals
– Can be regenerated quickly
• Nonrenewable – minerals, fossil fuels, and
soil.
– Formed slowly by geologic processes.
– Cannot be regenerated quickly.
MINERALS, ROCKS, AND THE
ROCK CYCLE
 The
earth’s crust consists of solid inorganic
elements and compounds called minerals
that can sometimes be used as resources.

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.
General Classification of
Nonrenewable Mineral Resources
 The
U.S. Geological Survey classifies
mineral resources into four major categories:




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
GEOLOGIC PROCESSES
 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:



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
ENVIRONMENTAL EFFECTS OF
USING MINERAL RESOURCES
 The
extraction, processing, and use of
mineral resources has a large environmental
impact.
Figure 15-9
Surface
mining
Metal ore
Separation
of ore from
gangue
Smelting
Recycling
Melting
metal
Conversion
to product
Discarding of
product
(scattered in
environment)
Fig. 15-9, p. 344
Mining – Excavation of earth for the purpose of
extracting ore or minerals
• Metallic Minerals – mined for metals (Zn) which can
be extracted through smelting.
• Nonmetallic Minerals – mined to be used in their
natural state (salt, gems).
• Mineral Deposit – area in which a particular mineral
is concentrated
• Ore - rock or mineral from which a valuable
substance can be extracted for a profit
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
Types of Metals
• Abundant Metals: concentration >0.1% in the
earth’s crust
– Iron, Aluminum, Silicon, Magnesium, Titatnium,
Manganese
• Scarce Metals: <0.01% in the crust
–
–
–
–
Ferro-alloys: Nickel, Chromium
Base Metals: Copper, Lead, Zinc
Precious or Noble Metals: Gold, Silver, Platinum
Special Metals: Gallium, Arsenic, Germanium,
Rare earths, Berrylium, Scandium etc..
Highly Uneven Distribution
S Africa
Chile
50% Gold
75% Chromium
90% Platinum Group
50% Molybdenum
15% Lead
30% Copper
Cuba
40% Nickel
Guinea and Australia
25% each of Aluminum
Zaire
50% cobalt
USA
Mineral Supply and Demand
• World Scenario:
– Assumptions:
• Present demand = present production
• Future projection is based on constant 1995 figures
• Unrestricted distribution
– Iron, Aluminum, Chromium, Cobalt and Platinum
will last centuries
– Copper, Lead, Zinc, Gold and Silver will last
several decades only
– Ditto for phosphates and sulfur
• Alleviating Factors:
– More exploration
– Better technology
– Reclassification of sub-economic resources to
reserve
Reduce Consumption?
– New technology adds to the existing needs
e.g., cellular phones, computers, microwave
oven
– In the US, population grew by 65% and
consumption grew by 130% between 19501990
– Great demand for resources in the
developing countries where there is a
genuine need and where the great majority
lives
• If demand cannot be reduced, supplies must be
increased or extended
Conservation - Recycling
– In USA 60% of lead, 40% of copper, 1/3rd of nickel and
almost ¼ of Al, Cr, Co and Zn is recycled
– Recycled Al requires 20 times less energy than new Al
– Difficult to do with finished products like cars or fridges
– Special problem with alloys
– Road salt, fertilizers, lead in gasoline gets too disperse
– Reduces waste disposal problem
Metals are emitted in air
during…
Mining, smelting, refining, Manufacturing and
Recycling
Air emissions are mostly particulates
Particulates fall out by gravity or wash out by rain
Soil
Vegetation
Water
Impact of Mining Activities
Mining Hazards
• Most hazardous activity in the US:
Activity
Mining
Deaths per 100,000
workers (1989)
43
Agriculture
40
Construction
32
Life Cycle of a Metal Resource
Surface
mining
Metal ore
Separation
of ore from
gangue
Smelting
Melting
metal
Conversion
to product
Recycling
Smelting – heating to release metals but creating air polluting byproducts
Chemical removal processes such as using cyanide to remove gold can
create Toxic holding ponds
Discarding
of product
Surface Mines
• Open pit mines
– Where large 3D ore body lies close to the surface
– Leaves a large exposed hole on the surface
– Exposed rocks prone to weathering and polluting
• Strip mines
– Mostly for coal where minerals occur in layers paralleling
the surface
– Waste rocks dumped back as spoil banks
– Newer regulations require reclamation involving grading,
restoring, and replanting
– Can cause changes in topography and drainage
Extracting Mineral Deposits
• Surface mining - shallow deposits
in US extracts 90% of non-fuel minerals and rocks
and 60% of the coal.
– Overburden – soil and rock overlying deposit.
– Spoils – discarded overburden
Open-pit Mining
Area Strip Mining
Mountaintop Removal
Figure
Extracting Mineral Deposits
• Subsurface (Shaft) mining - deposits that
are too deep for surface mining
– Disturbs less
– produces less waste
– but also less effective
– dangerous.
Underground Mines
• Generally less disruptive than surface
mines
• Tunnels closely follow the ore body
• Some waste rock on the surface
• Shallow abandoned mines can cause
collapse
Sources of Metal Pollution
• Mining
– Air
– Water
– Land
• Fossil Fuel Combustion
– Air
– Water
– Land
Harmful Environmental Effects of
Mining
• Acid Mine
Drainage (AMD)
• Heavy Metal
Contamination
• Processing
chemical pollution
• Erosion and
Sedimentation
99 tons of waste for every ton of Copper
Acid Mine Drainage (AMD)
– Sulfur in ores react with water and oxygen to
form sulfuric acid which leaks out from the
mine
• Bacteria in acid water hastens the process
– Acid is carried off the mine site by rainwater
or surface drainage and deposited into nearby
streams, rivers, lakes and groundwater. AMD
severely degrades water quality, and can kill
aquatic life and make water virtually unusable.
Acid Mine Drainage
Heavy Metal Contamination &
Leaching
• Heavy metal pollution is caused when such
metals as arsenic, cobalt, copper, cadmium,
lead, silver and zinc contained in excavated
rock or exposed in an underground mine come
in contact with water.
– Metals are leached out and carried downstream as
water washes over the rock surface.
– leaching is particularly accelerated in the low pH
conditions such as are created by Acid Mine
Drainage.
3. Processing Chemicals Pollution
– occurs when chemical agents (such as cyanide or sulphuric
acid used by mining companies to separate the target
mineral from the ore) spill, leak, or leach from the mine site
into nearby water bodies.
• These chemicals can be highly toxic to humans and wildlife.
4. Erosion and Sedimentation
– erosion of the exposed earth may carry substantial amounts
of sediment into streams, rivers and lakes.
– Excessive sediment can clog riverbeds and smother
watershed vegetation, wildlife habitat and aquatic
organisms.
Mineral Processing
• Crushing of ores produces tailings (waste)
• Traces of pollutants like mercury, arsenic, cadmium
and uranium may leach out of tailings and
contaminate groundwater and landfills
• Processing chemicals (e.g., Cyanide) are major
hazards
• Smelting releases toxic elements, SO2 etc and causes
acid rain which can destroy vegetation
Four PBT Metals
•
•
•
•
•
PBT: Persistent, Bio-accumulative, Toxic
Lead
Mercury
Cadmium
Arsenic
Lead; Adverse Effects
• Affects Nervous system of human fetus
and small children
• Most of the lead is stored in bones and
along with Calcium, is released in mother’s
milk
• Affects IQ, causes delinquency, kidney
cancer
• In adults: affects nervous system and
kidney, anemia, infertility
Sources of Lead
• Similar to other metals: mining, smelting,
coal burning power plants, incinerators
• Lead paints , lead contaminated soil,
plumbing
– affects children in poorer households
– Made worse by poor diet low in Ca and Fe
• For people living in Lead free environment:
– Food is the major source
Sources of Lead
• Gasoline
– Lead level in exhausts fell 90% after banning of lead
in gasoline – the substitute, Benzene, is carcinogen
– Lead in the blood of Children fell to 4 -6 microgram/lt
(threshold: 10 micrograms/lt)
– Major problem now in China
• The following are banned:
– Lead in gasoline, in paint, in printing ink, in solders in
plumbing and cans, in sealing wine bottles, in toys
– Imported products can still have lead
– Car batteries still contain lead
Mercury
• Much of the mercury in the environment originates as mercury
vapor from coal burning power plants and incinerators (2-3000
tons) and from natural sources (2700 to 6000 tons)
• Elemental Mercury not as injurious as methylmercury
• Most of the mercury ends up in the ocean where bacteria in the
bottom sediments convert elemental mercury to methylmercury
• Methylmercury biomagnifies up the food chain
– Some game fish has Hg conc. 200,000 X that of surrounding
water
– Can cause problems to humans eating these fish,
particularly among children, old people and pregnant women
Adverse effects of Mercury
• 95% of the exposure comes from eating
contaminated fish.
• Toxic to nervous system
• Minamata Tragedy:
– Chisso Corp discharged mercury in Minamata bay
from 1930
– Biomagnification in Fish upto 40 ppm (0.5 ppm safe
limit)
– 200,000 people were poisoned
– Chronic nervous system damage, miscarriages,
deformed fetus
– Settled in 1996 after 30 years of litigation
Reducing Risk from Mercury
• Regulations: EPA has set standards for
drinking water, air-emissions and is tackling
the biggest source: coal burning power plants
• Reduce workplace exposure
• Reduce or eliminate mercury containing
products:
–
–
–
–
In rechargeable batteries and button cells
Remove batteries from municipal solid waste
Green Lights program: Hg free fluorescent light
Phase out mercury from hospital and lab products
Cadmium
•
•
•
•
•
Discovered in 1817, heavily mined since mid-40s
Bioaccumulates in kidney – increases with age
Itai-itai disease among older women in Japan
Cancer, birth defects in rats
Sources:
–
–
–
–
Mining and smelting of Zn, Pb, Cu
Coal burning
Phosphatic fertilizers, sewage sludge
Nicad batteries: a major source in Municipal Solid
Waste
Cadmium…
• 90% of the exposure (of non-smokers) is
through food
– Fish, scallops and oysters
– Liver and kidneys of larger animals : beef,
venison
– Readily taken up by plants – concentrated in
Tobaccos. 90% of inhaled Cd is absorbed by
the body
• Control: EPA regulations
• Power plants still not controlled
• Nicad batteries still a major problem
Arsenic
•
•
•
•
Metal smelting of Copper and Lead
Used to be common weed killer
Emitted by volcanoes
Naturally present in soil
– Major environmental problem in Bangladesh
• Level in seafoods higher than in land-grown food.
• Much of the Arsenic in Food is not bioavailable
• CCA (Chromated Copper Arsenate) used to treat
wood including playground equipments – can
contaminate soil
SUPPLIES OF MINERAL
RESOURCES
 Depletion
curves
for a renewable
resource using
three sets of
assumptions.

Dashed vertical
lines represent
times when 80%
depletion occurs.
Figure 15-16
Production
A
Mine, use, throw away;
no new discoveries;
rising prices
Recycle; increase reserves
by improved mining
technology, higher prices,
and new discoveries
B
Recycle, reuse,
reduce consumption;
increase reserves by
improved mining
technology, higher
prices, and new
discoveries
C
Present Depletion Depletion Depletion
time A
time B
time C
Time
Fig. 15-16, p. 348
SUPPLIES OF MINERAL
RESOURCES
 New
technologies can increase the mining of
low-grade ores at affordable prices, but
harmful environmental effects can limit this
approach.
 Most minerals in seawater and on the deep
ocean floor cost too much to extract, and
there are squabbles over who owns them.
Getting More Minerals from the
Ocean
 Hydrothermal
deposits form when
mineral-rich
superheated water
shoots out of vents
in solidified magma
on the ocean floor.
Figure 15-17
Black
smoker
White
smoker
Sulfide
deposits
Magma
White
crab
White clam
Tube
worms
Fig. 15-17, p. 350
USING MINERAL RESOURCES
MORE SUSTAINABLY
 Scientists
and engineers are developing new
types of materials as substitutes for many
metals.
 Recycling valuable and scarce metals saves
money and has a lower environmental impact
then mining and extracting them from their
ores.
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
Case Study:
The Ecoindustrial Revolution
 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.

Industries can interact in complex resource
exchange webs in which wastes from
manufacturer become raw materials for another.
Sludge
Pharmaceutical plant
Sludge
Greenhouses
Waste
heat
Fish farming
Waste heat
Oil refinery
Surplus
sulfur
Local farmers
Surplus
Electric power
natural gas
plant
Waste
calcium
sulfate
Cement manufacturer
Sulfuric acid
producer
Wallboard factory
Area homes
Fig. 15-19, p. 352