Transcript Chapter 14 Geology and Nonrenewable

Chapter 14 Geology and
Nonrenewable Resources
Post Reading Discussion
Contents
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1b. Describe the environmental effects
of gold mining.
• Tons of mining waste
– Pollutes air and nearby surface water
• Cyanide heap leaching
– Cyanide salts used to extract gold
– Extremely toxic, interferes with cell metabolism
– Holding ponds of can leak or overflow
contaminating groundwater and nearby lakes and
streams
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Fig. 14-1, p. 344
2a. Define geology, core, mantle, crust,
tectonic plate, and lithosphere.
• Science of studying the dynamic processes
occurring on the earth’s surface and its interior.
• Earth’s inner most zone; extremely hot solid inner
core surrounded by liquid core.
• Surround the core, thick zone, mostly solid rock,
but lower part—the asthenosphere—is hot and
partly melted rock that flows.
• Outermost and thinnest zone.
• The broken sections of crust that move atop of
flowing mantle.
• Continental and oceanic crusts and upper part of
mantle.
Volcanoes
Abyssal hills
Abyssal Oceanic
ridge
floor
Abyssal
floor Trench
Folded mountain
belt
Craton
Abyssal
plain
Oceanic crust
(lithosphere)
Mantle (lithosphere)
Continental crust (lithosphere)
Continental
Continental
shelf
slope
Continental
rise
Mantle (lithosphere)
Mantle
(asthenosphere)
Fig. 14-2, p. 346
Spreading center
Ocean trench
Subduction zone
Oceanic crust
Oceanic crust
Continental crust
Continental crust
Material cools as Cold dense
it reaches the material falls
outer mantle back through
mantle
Hot material
Mantle
rising
through
convection
the mantle
cell
Two plates move towards
each other. One is
subducted back into the
mantle on a falling
convection current.
Mantle
Hot outer
core
Inner core
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Fig. 14-3, p. 346
2b. What is a transform fault?
• Boundary between tectonic plates where the
plates slide and grind past one another along
the fracture (fault) in the lithosphere.
EURASIAN PLATE
JUAN DE FUCA
PLATE
NORTH
AMERICAN
PLATE
CARIBBEAN PLATE
PACIFIC PLATE
COCOS PLATE
ANATOLIAN PLATE
CHINA SUBPLATE
PHILIPPINE
PLATE
AFRICAN PLATE ARABIAN PLATE
INDIA
PLATE
SOUTH AMERICAN
PLATE
NAZCA PLATE
PACIFIC
PLATE
AUSTRALIAN PLATE
SOMALIAN
SUBPLATE
SCOTIA PLATE
ANTARCTIC PLATE
Divergent plate boundaries
Convergent plate
boundaries
Transform faults
Fig. 14-4, p. 347
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Fig. 14-5, p. 348
2c. What is weathering and why is it
important?
• There are internal and external geologic
processes.
• Weathering is an external geologic process
that is the physical, chemical and biological
breakdown of rocks.
• Helps build soil—important for sustaining
terrestrial ecosystems.
Parent material
(rock)
Biological
weathering
(tree roots and
lichens)
Chemical
Physical weathering
weathering (water, (wind, rain, thermal
acids, and gases) expansion and
contraction, water
freezing)
Particles of parent material
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Fig. 14-6, p. 348
2d. Define volcano and describe the nature
and effects of a volcanic eruption.
• Volcano occurs when magma reaches the
earth’s surface though a central vent or long
crack called a fissure; occur at tectonic plate
boundaries.
• Rocks, lava, hot ash, gases (water, CO2 and
SO2)
• Mt. Pinatubo, 1991. Mt. St. Helens, 1980
• Benefits? Created mountains, highly fertile
soils.
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Fig. 14-7, p. 349
2e. Define and describe the nature and
effects of an earthquake.
• Earthquakes occur when a fault forms or there is
an abrupt movement of an existing fault releasing
energy that has accumulated over time in the
form of seismic waves.
• Severity is related to magnitude of seismic waves
measure by the Richter scale (a log base 10 scale)
• Primary effects: Shaking and sometime
permanent vertical or horizontal displacement of
the ground
• Can cause damage to building and infrastructure
and represents a life hazard to people living in
areas prone to earthquakes.
Liquefaction of recent
sediments causes
buildings to sink
Landslides may
occur on hilly
ground
Two adjoining plates
move laterally along the
fault line
Earth movements
cause flooding in
low-lying areas
Shock
waves
Epicenter
Focus
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Fig. 14-8, p. 350
2f. What is a tsunami and what are its
effects?
• Tsunami is a series of large waves generated
when part of the ocean floor suddenly rises or
drops—caused by thrust faults in the ocean
floor.
• Kill people and destroy property when the
wave reaches shore
– Largest loss occurred in December 2004
• 9.15 magnitude earthquake in the Indian Ocean
• Generated waves 100 ft
• Killed an estimated 228 000 people.
Earthquake in seafloor swiftly
pushes water upwards, and
starts a series of waves
Waves move rapidly in
deep ocean reaching
speeds of up to 890
kilometers per hour.
As the waves near land they
slow to about 45 kilometers per
hour but are squeezed upwards
and increased in height.
Waves head inland
causing damage in
their path.
Undersea thrust fault
Upward wave
Bangladesh
Burma
India
Thailand
Earthquake
Sri Lanka
Malaysia
Indonesia
Sumatra
December 26, 2004, tsunami
Fig. 14-11, p. 352
Fig. 14-12a, p. 352
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Fig. 14-12b, p. 352
3a. Define mineral, rock, sedimentary rock, igneous rock,
and metamorphic rock and give and example of each.
• A mineral is an element or inorganic compound that occurs naturally in the
earth’s crust as a solid with a regular crystalline structure.
• A rock is a solid combination of one or more minerals found in the earth’s
crust.
• Sedimentary rocks are made of sediments—dead plant and animal remains
and weathered rocks.
– Examples: Sandstone and shale (from sand), dolomite and limestone
(from compacted shells, skeletons, and other remains of dead
organisms, lignite and bituminous coal (derived from plant material)
• Igneous rocks form below the earth’s surface when magma wells up from
the earth’s upper mantle or deep crust and then cools and hardens.
– Examples: Granite (formed underground) and lava (for above ground)
• Metamorphic rocks form when a preexisting rock is subjected to high
temperatures and/or pressures, and/or chemically active fluids causing a
change in the crystalline structure, physical properties and appearance.
– Examples: anthracite (from coal), slate (from shale or mudstone) and
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marble (from limestone).
3b. Describe the nature and importance
of the rock cycle.
• Physical and chemical processes that change
rocks from one form to another; recycle
earth’s three types of rocks over millions of
years.
• Concentrates the planet’s nonrenewable
mineral resources on which our life processes
and economies depend.
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Fig. 14-13, p. 354
4a. Define mineral resource and list
three types of such resources.
• Mineral resource is a concentration of naturally
occurring material from the earth’s crust that can
be extracted and processed into useful products
and raw materials at an affordable cost.
• Three types:
– Fossil fuels (such as coal)
– Metallic minerals (e.g., Al, Fe, Cu)
– Nonmetallic minerals (e.g., sand, gravel, limestone)
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4b. Define ore and distinguish between
high-grade and low-grade ore.
• Ore is rock that contains a large enough
concentration of a particular mineral—often a
metal—to make it profitable for mining and
processing.
• High-grade ore contains fairly large amounts of
the desired nonrenewable mineral resource.
• Low-grade ore contains a lesser concentration of
the desired mineral resource.
– More costly both financially and environmentally to
mine.
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4c. What are reserves?
• A reserve is an identified resource from which
a mineral can be extracted profitably at
current prices.
– Change as
• Reserves are used
• New reserves are found
• New technology makes it profitable to tap mineral
deposits previously too expensive to mine.
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4d. Describe the life cycle of a metal
resource.
Surface mining
Metal ore
Separation of
ore from
gangue
Smelting
Melting
metal
Conversion to
product
Discarding of
product
Recycling
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Fig. 14-14, p. 355
4e. Describe the major harmful effects of extracting,
processing, and using nonrenewable resources.
• Takes tremendous amounts of energy and
disturbs land, erodes soil, produces solid
waste, and pollutes the air, water and soil.
• Are there benefits for such activities? (See p.
355, right column, first paragraph.)
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
Transportation,
purification,
manufacturing
Use
Transportation or transmission
to individual user, eventual use,
and discarding
Solid wastes; radioactive
material; air, water, and soil
pollution; noise; safety and
health hazards; ugliness; heat
Noise; ugliness; thermal water
pollution; pollution of air, water,
and soil; solid and radioactive
wastes; safety and health
hazards; heat
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Fig. 14-15, p. 356
5a. Distinguish between surface
mining and subsurface mining.
• Depends on mineral deposits. Are they
shallow or deep underground?
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5b. Define overburden, spoils, and
open-pit mining.
• Overburden is the soil and rock overlying
useful mineral deposits.
• Spoils – discarded overburden.
– When deposits are dredged from streams, the
unused materials or tailings are usually left on
land.
• Open-pit mining is a type of surface mining in
which machines dig holes and remove ores.
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Fig. 14-16, p. 356
5c. Define strip mining and distinguish among area strip
mining, contour strip mining, and mountaintop removal.
• Strip mining is a type of surface mining in which
bulldozers, power shovels, or stripping wheels
remove large chunks of the earth’s surface in
strips; useful and economical when deposits lie
close to surface in large horizontal beds.
• Area strip mining used where topography is fairly
flat.
• Contour strip mining used mostly to mine on hilly
or mountainous terrain.
• Mountaintop removal
Fig. 14-17, p. 357
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Fig. 14-19, p. 358
5d. Describe the harmful environmental effects of mining.
• Long-term harm to environment
• Scarring and disruption of land surface
• Spoil banks
– Spoils and tailing susceptible to chemical weathering and erosion by water and
wind.
– Re-growth of vegetation is slow because not topsoil
• Mountaintop removal
– Waste rock and dirt pushed into valleys, destroying forests, burying streams, and
increasing flood hazards.
– Toxic wastewater from coal processing, stored in valleys behind coal waster
sludge dams; contain toxic selenium, arsenic, and mercury.
– EPA: 1200 mi or rivers and streams buried in Appalachia
– 470 of largest mountain have disappeared.
– In 2007, U.S. DOI allowed this mining to continue w/ expanded easier dumping
into streams.
•
•
•
•
Hydraulic mining for AU in tropical forest and other tropical areas
Subsurface mining: health and life hazards, subsidence
Lost of solid waste
Major pollution of water and air
– E.g., acid mine drainage (caused by aerobic bacteria act on iron sulfide producing
H2SO4) to nearby streams.
Fig. 14-18, p. 357
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Fig. 14-20, p. 358
5e. What is smelting and what are its
major harmful environmental effects?
• Smelting is the use of heat and/or chemical
solvents to extract metals from ores.
• Harmful environmental effects
– Process emits huge amounts of pollutants
including SO2, which damages vegetation and
acidifies the soil.
– Water pollution and liquid and solid and solid
hazardous wastes that need safe (or is it safer?)
disposal.
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Fig. 14-22, p. 360
5f. What five nations supply most of the world’s
nonrenewable mineral resources
• Mineral deposits are not distributed evenly.
• Some minerals are particularly scarce:
– Examples: Mn, Cr, Co, and Pt
• Five countries that supply the most
nonrenewable mineral resources used by
modern societies:
– U.S.A., Canada, Russia, South Africa, and
Australia
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5g. How dependent is the United States on
other countries for important nonrenewable
mineral resources?
• Has been a sharp rise in the total per capita use
of nonrenewable mineral resources in the United
States.
• Depleted once rich deposits including Pb, Al, and
Fe.
• Depends on imports of 50% or more of 24 of its
most important nonrenewable minerals.
• Experts concerned over four strategic metal
resources—Mn, Co, Cr, and Pt—essential for
economic and military strength.
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6a. Describe the advantages and disadvantages
of the nanotechnology revolution.
• R&D possibilities, limitless; manufacturing with little
environmental harm w/o depleting nonrenewable
resources, and w/ many potential environmental
benefits.
• Mining and processing of most mineral resources could
become obsolete businesses eliminating the harmful
effects of mining and processing mineral resources.
• As with any technology, unintended consequences.
– Potential health effect of nanoparticles; small particles,
more toxic and more reactive.
– Loss of businesses and jobs causing severe social and
economic stress as entire industries disappear.
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6b. What are five possible solutions when
a mineral becomes economically depleted?
• Two factors determine future supply of a mineral:
actual potential supply and the rate at which we
use it.
• When a mineral become economically
depleted—What does this mean?—there are five
solutions:
–
–
–
–
–
Recycle or reuse existing supplies
Waste less
Use less
Find a substitute
Do without
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6c. Define depletion time and describe three
types of depletion curves for a mineral resource.
• Depletion time it the time it takes to use up a
certain proportion—usually 80%—of the
reserves of a mineral at a given rate of use.
• Depletion curves are used to estimate the
depletion time. Three types depend different
sets of assumptions (Figure 14-23).
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Fig. 14-23, p. 361
6d. Describe the conventional view of the
relationship between the supply of a mineral
resource and its market price.
• Standard economic theory
– In a competitive market, a plentiful mineral resource is
cheap when supply exceeds demand.
– When the resource become scarce, prices go up.
Encourages:
•
•
•
•
•
Exploration for new deposits
Development of better mining technologies
Mining of lower-grade ore, as this become more profitable.
Search for substitutes
Resource conservation
• In developed countries, such price effect may no
longer apply. Why?
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6e. What factors can influence the market
interaction between mineral resource supply
and market price.
• Subsidies, taxes, regulations and import tariffs are used to
control supplies, demands, and prices.
• Government subsidies keep mineral prices artificially low
which can promote development of domestic mineral
resources to help economic growth national security.
• However, Such subsidies are hidden cost to taxpayers that
promote environmental degradation, due to extraction and
processing, and waste.
– If these hidden cost were included in the market prices, this
would encourage recycling and reusing and the search for
substitutes. Would also reduce pollution.
– The mining industry insists that they need taxpayer subsidies
and low taxes to keep prices of minerals low for consumers.
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6f. Describe the benefits and possible
drawbacks of nanotechnology.
• See answer to 6a.
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6g. Discuss the pros and cons of the
U.S. General Mining Law of 1872.
Under this law, a person or
corporation could:
•File a claim or assume legal
ownership of pieces of U.S. public
lands, except national parks and
wilderness.
•$500 for a claim plus $120 per
year to maintain claim.
•Buy for $6-12 per hectare ($2.505.00 per acre)
Pros
• Encouraged mineral exploration
and hard rock mineral mining.
Cons
• Provides very little accountability
for mining co’s for cleanup and
restoration of mined areas.
• Some companies have purchased
land worth millions of dollars for
a few hundred dollars. A “license
to steal” from U.S. citizens
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7a. Describe the opportunities and limitations of
increasing mineral supplies by mining lower-grade ores.
Opportunities
• New earth-moving
equipment, techniques for
removing impurities, and
other technologies in
extraction and processing.
• Lower grade ores are
currently being used
– Example: in 1900 copper ore
was 5% by weight, now it is
0.5%.
Limitations
• Increased cost of mining
and processing
• Limited freshwater needed
to mine and process, esp. in
arid areas
• Environmental impact of
increased land disruption,
waster material, and
pollution
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7b. What are the advantages and
disadvantages of biomining?
Advantages
• Microbes can extract a
desired metal from ore
while leaving the
surrounding environment
undisturbed.
• Reduces air pollution from
smelting
• Reduces water pollution,
e.g. from cyanide heap
leaching for Au
Disadvantages
• Process is slow and
currently only feasible for
low-grade ores in which
conventional techniques are
too expensive.
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8a. Describe the opportunities and limitations of
getting more minerals from the ocean.
Opportunities
• In seawater: Mg, Br, and NaCl
• In sediments of continental
shelf and near shore: sand,
gravel, phosphates, S, Sn, Cu,
Fe, W, Ag, Ti, Pt, and diamonds
• Near hydrothermal vents:
when magma solidifies
particles of metal compounds
precipitate out including
sulfides, Ag, Zn, and Cu.
• Manganese nodules of the
Pacific Ocean floor.
Limitations
• Cost for mining some
mineral may be too
expensive, specially those of
low concentration in sea
water
• Who owns these minerals in
open ocean
• Effects of mining on ocean
floor ecosystem/food webs
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9a. Describe the opportunities and limitations of
finding substitutes for scarce mineral resources
and recycling and reusing valuable metals.
Opportunities
Limitations
• Ceramics and plastics being used
as replacements for metals.
• Nanotechnology may lead to
development of substitutes.
• Grancrete: Styrofoam and
ceramic.
• Plastic for pipes
• Plastic and composite materials
for automobile and aerospace
industry
• Plastic and gels for
superinsulation
• Plastics from plant materials
• Plastics require the use of fossil
fuels, which are nonrenewable
and have their own
environmental impacts.
• Substitutes for scare materials
may not always be possible: e.g.,
Pt as an industrial catalyst and Cr
in stainless steel.
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9b. Describe ways of using nonrenewable
mineral resources more sustainably.
• Recycle and reuse
– Besides being sustainable practices for mineral
use, has much lower environmental impact.
• Example: Recycling Al produces 95% less air pollution,
97% less water pollution, and uses 95% less energy
than mining and processing Al ore.
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Fig. 14-24, p. 366
9c. Describe the Pollution Prevention Pays program of
the Minnesota Mining and Manufacturing Company.
• In answer the question, how can we reduce use
and waste, 3M developed the 3P program.
– Redesigned equipment and processes
– Used fewer hazardous raw materials
– Identified toxic chemical outputs and recycled or sold
them as raw materials to other companies
– Began making more nonpolluting products
• By 1998, waste production was down by 1/3, air
pollution per unit of production was down 70%,
and 3M saved $750 million in waste disposal and
material costs.
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9d. What is an industrial ecosystem?
• Making industrial manufacturing cleaner and
more sustainable by redesigning them to
mimic how nature deals with wastes.
• Might include recycling and reusing most
minerals and chemicals instead of dumping
them into the environment.
• Resource exchange webs – waste of one
manufacturer become the raw materials of
another, similar to a food web in nature.
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9e. Describe the industrial ecosystem
operating in Kalundborg, Denmark.
• Collaboration between an electric power plant
and nearby industries, farms, and homes to
save money and reduce outputs of waste and
pollution.
• Reduces the flow of nonrenewable mineral
and energy resources through their economy.
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Fig. 14-25, p. 367
10a. Describe the relationship between gold
mining and the four scientific principles of
sustainability.
• See p. 367, Revisiting: Gold Mining and
Sustainability.
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