Geology and Nonrenewable Mineral Resources

1
Chapter 15

• Geology and Nonrenewable Mineral Resources

2
Chapter Overview Questions

• What major geologic processes occur within the
  earth and on its surface?
• What are nonrenewable mineral resources and where
  are they found?
• What are rocks, and how are they recycled by the
  rock cycle?
• How do we find and extract mineral resources from
  the earths crust, and what harmful environmental
  effects result from removing and using these
  minerals?

3
Chapter Overview Questions (contd)

• Will there be enough nonrenewable mineral
  resources for future generations?
• Can we find substitutes for scarce nonrenewable
  mineral resources?
• How can we shift to more sustainable use of
  nonrenewable mineral resources?

4
Core Case Study The Nanotechnology Revolution

• Nanotechnology uses science and engineering to
  create materials out of atoms and molecules at
  the scale of less than 100 nanometers.
• Little environmental harm
• Does not use renewable resources.
• Potential biological concerns.
• Can move through cell membranes

Figure 15-1
5
GEOLOGIC PROCESSES

• 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 earths 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.

6
GEOLOGIC PROCESSES

• Major features of the earths crust and upper
  mantle.

Figure 15-2
7

Spreading center
Ocean trench
Collision between two continents
Oceanic tectonic plate
Oceanic tectonic plate
Plate movement
Plate movement
Tectonic plate
Oceanic crust
Oceanic crust
Subduction zone
Continental crust
Continental crust
Material cools as it reaches the outer mantle
Cold dense material falls back through mantle
Hot material rising through the mantle
Mantle convection cell
Mantle
Two plates move towards each other. One is
subducted back into the mantle on a falling
convection current.
Hot outer core
Inner core
Fig. 15-3, p. 337
8
GEOLOGIC PROCESSES

• Huge volumes of heated and molten rack moving
  around the earths interior form massive solid
  plates that move extremely slowly across the
  earths surface.
• Tectonic plates huge rigid plates that are moved
  with convection cells or currents by floating on
  magma or molten rock.

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The Earths Major Tectonic Plates
Figure 15-4
10
The Earths 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
11

Fig. 15-4, p. 338
12

EURASIAN PLATE
NORTH AMERICAN PLATE
ANATOLIAN PLATE
CARIBBEAN PLATE
JUAN DE FUCA PLATE
CHINA SUBPLATE
ARABIAN PLATE
PHILIPPINE PLATE
AFRICAN PLATE
PACIFIC PLATE
SOUTH AMERICAN PLATE
NAZCA PLATE
INDIA-AUSTRALIAN PLATE
SOMALIAN SUBPLATE
ANTARCTIC PLATE
Divergent plate boundaries
Convergent plate boundaries
Transform faults
Fig. 15-4a, p. 338
13

Trench
Volcanic island arc
Craton
Transform fault
Lithosphere
Rising magma
Lithosphere
Subduction zone
Lithosphere
Asthenosphere
Asthenosphere
Asthenosphere
Divergent plate boundaries
Convergent plate boundaries
Transform faults
Fig. 15-4b, p. 338
14
GEOLOGIC PROCESSES

• The San Andreas Fault is an example of a
  transform fault.

Figure 15-5
15
Wearing Down and Building Up the Earths Surface

• Weathering is an external process that wears the
  earths surface down.

Figure 15-6
16

Parent material (rock)
Biological weathering (tree roots and lichens)
Chemical weathering (water, acids, and gases)
Physical weathering (wind, rain, thermal
expansion and contraction, water freezing)
Particles of parent material
Fig. 15-6, p. 340
17
MINERALS, ROCKS, AND THE ROCK CYCLE

• The earths 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 earths crust
  that can be extracted and processed into useful
  materials at an affordable cost.

18
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

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General Classification of Nonrenewable Mineral
Resources

• Examples are fossil fuels (coal, oil), metallic
  minerals (copper, iron), and nonmetallic minerals
  (sand, gravel).

Figure 15-7
20

Undiscovered
Identified
Economical
Reserves
Other resources
Decreasing cost of extraction
Not economical
Decreasing certainty
Known
Existence
Fig. 15-7, p. 341
21
GEOLOGIC PROCESSES

• Deposits of nonrenewable mineral resources in the
  earths crust vary in their abundance and
  distribution.
• A very slow chemical cycle recycles three types
  of rock found in the earths crust
• Sedimentary rock (sandstone, limestone).
• Metamorphic rock (slate, marble, quartzite).
• Igneous rock (granite, pumice, basalt).

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Rock Cycle
Figure 15-8
23

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
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ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES

• The extraction, processing, and use of mineral
  resources has a large environmental impact.

Figure 15-9
25

Surface mining
Metal ore
Separation of ore from gangue
Smelting
Melting metal
Conversion to product
Discarding of product (scattered in environment)
Recycling
Fig. 15-9, p. 344
26

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
Solid wastes radioactive material air, water,
and soil pollution noise safety and health
hazards ugliness heat
Transportation, purification, manufacturing
Use
Noise ugliness thermal water pollution
pollution of air, water, and soil solid and
radioactive wastes safety and health hazards
heat
Transportation or transmission to individual
user, eventual use, and discarding
Fig. 15-10, p. 344
27
ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES

• Minerals are removed through a variety of methods
  that vary widely in their costs, safety factors,
  and levels of environmental harm.
• A variety of methods are used based on mineral
  depth.
• Surface mining shallow deposits are removed.
• Subsurface mining deep deposits are removed.

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Open-pit Mining

• Machines dig holes and remove ores, sand, gravel,
  and stone.
• Toxic groundwater can accumulate at the bottom.

Figure 15-11
29
Area Strip Mining

• Earth movers strips away overburden, and giant
  shovels removes mineral deposit.
• Often leaves highly erodible hills of rubble
  called spoil banks.

Figure 15-12
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Contour Strip Mining

• 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
31

Undisturbed land
Overburden
Highwall
Coal seam
Overburden
Pit
Bench
Coal seam
Spoil banks
Fig. 15-13, p. 346
32
Mountaintop Removal

• Machinery removes the tops of mountains to expose
  coal.
• The resulting waste rock and dirt are dumped into
  the streams and valleys below.

Figure 15-14
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Mining Impacts

• Metal ores are smelted or treated with
  (potentially toxic) chemicals to extract the
  desired metal.

Figure 15-15
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SUPPLIES OF MINERAL RESOURCES

• The future supply of a resource depends on its
  affordable supply and how rapidly that supply is
  used.
• A rising price for a scarce mineral resource can
  increase supplies and encourage more efficient
  use.

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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
36

A
Mine, use, throw away no new discoveries rising
prices
Recycle increase reserves by improved mining
technology, higher prices, and new discoveries
B
Production
Recycle, reuse, reduce consumption increase
reserves by improved mining technology, higher
prices, and new discoveries
C
Present
Depletion time A
Depletion time B
Depletion time C
Time
Fig. 15-16, p. 348
37
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.

38
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
39

Black smoker
White smoker
Sulfide deposits
Magma
White clam
White crab
Tube worms
Fig. 15-17, p. 350
40
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.

41

Solutions
Sustainable Use of Nonrenewable Minerals
Do not waste mineral resources.
Recycle and reuse 6080 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
42
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.

43
Case Study The Ecoindustrial Revolution
Figure 15-19
44

Sludge
Pharmaceutical plant
Local farmers
Sludge
Greenhouses
Waste heat
Waste heat
Waste heat
Fish farming
Waste heat
Surplus natural gas
Electric power plant
Fly ash
Oil refinery
Surplus sulfur
Waste calcium sulfate
Waste heat
Cement manufacturer
Surplus natural gas
Sulfuric acid producer
Wallboard factory
Area homes
Fig. 15-19, p. 352