Geology and Nonrenewable Minerals

1
Geology and Nonrenewable Minerals

• Chapter 15

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Environmental Effects of Gold Mining

• Gold producers
• South Africa
• Australia
• United States
• Canada
• Cyanide heap leaching
• Extremely toxic to birds and mammals
• 2000 Collapse of a dam retaining a cyanide leach
  pond

Black Hills S. Dakota
3
Earths Major Geological Processes and Hazards

• Gigantic plates in the earths crust move very
  slowly atop the planets mantle, and wind and
  water move the matter from place to place across
  the earths surface.
• Natural geological hazards such as earthquakes,
  tsunamis, volcanoes, and landslides can cause
  considerable damage.

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The Earth Is a Dynamic Planet

• What is geology?
• Three major concentric zones of the earth
• Core solid inner part surrounded by a liquid
  core
• Mantle mostly solid rock
• Including the asthenosphere hot,partly melted
  rock that flows and can be deformed like plastic
• Crust
• Continental crust
• Oceanic crust 71 of crust

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Major Features of the Earths Crust and Upper
Mantle
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The Earth beneath your feet is moving.

• Convection cells, or currents move large
  volumes of rock and heat in loops within the
  mantle like gigantic conveyer belts
• Tectonic Plates dozen or so huge rigid plates
  move extremely slowly atop the denser mantle on
  hot, soft rock in the underlying asthenosphere
• Lithosphere continental and oceanic crust and
  the rigid, outermost part of the mantle

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The Earths Crust Is Made Up of a Mosaic of Huge
Rigid Plates Tectonic Plates
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The Earths Major Tectonic Plates
EURASIAN PLATE
NORTH AMERICAN PLATE
ANATOLIAN PLATE
JUAN DE FUCA PLATE
CHINA SUBPLATE
CARIBBEAN PLATE
PHILIPPINE PLATE
ARABIAN PLATE
AFRICAN PLATE
INDIA PLATE
PACIFIC PLATE
PACIFIC PLATE
COCOS PLATE
SOUTH AMERICAN PLATE
NAZCA PLATE
AUSTRALIAN PLATE
SOMALIAN SUBPLATE
SCOTIA PLATE
ANTARCTIC PLATE
Divergent plate boundaries
Transform faults
Convergent plate boundaries
Fig. 14-4, p. 347
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The Earth beneath your feet is moving .

• Three types of boundaries between plates
• Divergent plates plates move apart
• Magma flows up through the resulting cracks
• Oceanic ridge some of which have higher peaks
  and deeper canyons than earths continents
• Convergent plates oceanic plate collides with a
  continental plate,
• Subduction the latter rides up over the
  denser oceanic plate and pushes it down into the
  mantle
• Subduction zone area where collision and
  subduction takes place
• Trench forms at the boundary between the 2
  converging plates
• Transform fault e.g. San Andreas fault where
  plates slide and grind past one another along a
  fracture. Most located on the ocean floor

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The San Andreas Fault as It Crosses Part of the
Carrizo Plain in California, U.S.
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Some Parts of the Earths Surface Build Up and
Some Wear Down

• Internal geologic processes
• Generated by heat from the earths interior
  ,generally build up the earths surface in the
  form of continental and oceanic crust including
  mountains and volcanoes
• External geologic processes
• Weathering driven directly or indirectly by
  energy from the sun(mostly in the form of flowing
  water and wind)
• Physical, Chemical, and Biological soil
• Erosion
• Wind
• Flowing water
• Human activities
• Glaciers

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Weathering Biological, Chemical, and Physical
Processes
13
Volcanoes Release Molten Rock from the Earths
Interior

• Volcano magma reaches the earths surface
  through a..
• Fissure central vent or a long crack
• Magma
• Lava magma that reaches the earths surface.
  Debris ranging from large chunks of larva rock to
  glowing hot ash, liquid lava and gases such as
  water vapor, carbon dioxide and sulfur dioxide .
  Much of the worlds volcanic activity is
  concentrated along the boundaries of the earths
  tectonic plates
• 1980 Eruption of Mount St. Helens
• 1991 Eruption of Mount Pinatubo cooled the
  earth average temperature for 15 months
• Benefits of volcanic activity highly fertile
  soil, creates outstanding landforms (Crater Lake
  in Oregon)

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Creation of a Volcano
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Earthquakes Are Geological Rock-and-Roll Events
Richter scale Insignificant lt4.0 Minor
4.04.9 Damaging 5.05.9 Destructive
6.06.9 Major 7.07.9 Great gt8.0
Earthquake Seismic waves Focus Epicenter Magnitud
e Amplitude
Foreshocks and aftershocks Primary effects of
earthquakes shaking, permanent vertical or
horizontal displacement of the ground
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Major Features and Effects of an Earthquake
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Areas of Greatest Earthquake Risk in the United
States
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Areas of Greatest Earthquake Risk in the World
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Earthquakes on the Ocean Floor Can Cause Huge
Waves Called Tsunamis

• Tsunami, tidal wave generated when part of the
  ocean floor suddenly rises or drops. Usually
  occurs offshore in subduction zones.
• Detection of tsunamis by ocean buoys, pressure
  recorders on the ocean floor which measures
  changes in water pressure as the waves pass over
  it data relayed via satellites tsunami warning
  systems
• December 2004 Indian Ocean tsunami
• Magnitude of 9.15
• Role of coral reefs and mangrove forests in
  reducing death toll

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Formation of a Tsunami and Map of Affected Area
of Dec 2004 Tsunami
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Shore near Banda Aceh,Gleebruk in Indonesia
before and after tsunami
After December 28, 2004
Before June 23, 2004
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Gravity and Earthquakes Can Cause Landslides

• Mass wasting detached or loose rock, soil and
  mud to slide down steep slopes near the shores of
  oceans or lakes
• Slow movement
• Fast movement
• Rockslides
• Avalanches
• Mudslides 1970 Peru, buried the town of
  Yungay and killed 17,000 people
• Effect of human activities on such geological
  events
• forest clearing, road building , crop growing,
  building houses

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Earths Rocks are Recycled..

• The three major types of rocks found in the
  earths crustsedimentary, igneous, and
  metamorphicare recycled very slowly by the
  process of erosion, melting, and metamorphism.

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There Are Three Major Types of Rocks

• Earths crust
• Composed of minerals and rocks
• Three broad classes of rocks, based on formation
• Sedimentary Igneous
• Sandstone Granite
• Shale Lava rock
• Dolomite Metamorphic
• Slate Anthracite
• Lignite Slate
• Bituminous coal Marble

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The Earths Rocks Are Recycled Very Slowly

• Rock cycle the interaction of physical and
  chemical processes that change rocks from one
  type to another. Slowest of the earths cyclic
  processes

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What Are Mineral Resources, and what are their
environmental effects?

• Some naturally occurring materials in the earths
  crust can be extracted and made into useful
  products in processes that provide economic
  benefits and jobs.
• 100 minerals naturally occurring material
• fossil fuels(coal)
• metallic(aluminum, iron, copper)
• non-metallic(sand, gravel,limestone)
• Ore large concentration of a particular mineral,
  often a metal
• High-grade ore large amount of desired
  non-renewable resource
• Low-grade ore small amount of the resource

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Mineral Use Has Advantages and Disadvantages

• Mine and convert minerals into useful products
• Disadvantages enormous amounts of energy,
  disturbs land, erode soil, produce solid waste,
  air and water pollution

Life cycle of a metal resource
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Extracting, Processing, Using Nonrenewable
Mineral and Energy Resources
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There Are Several Ways to Remove Mineral
Deposits

• Surface mining shallow deposits removed
• mechanized equipment strips away overburden(soil
  and rock overlay), discarded as waste called
• Used to extract 90 of the nonfuel mineral and
  rock resources and 6- of the coal
• Type of surface mining used depends on
• Resource
• Local topography
• Subsurface mining
• Deep deposits removed
• Used to extract coal and metal ores

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Types of Surface Mining

• Open Pit Mining machines dig hole and remove
  ore
• Strip Mining earth movers strip overburden and
  power shovels remove deposit
• Contour Mining mine coal on hilly terrain. Wall
  of dirt left in front of a highly erodible bank
  of soil and rock called highwall
• Mountain Top Removal Appalachian Mountains ,
  draglines, explosives remove top of mountain to
  expose seams

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Open-Pit Mine in Western Australia
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Undisturbed land
Overburden
Highwall
Coal seam
Overburden
Pit
Bench
Coal seam
Contour Strip Mining in hilly areas
Spoil banks
Fig. 14-17, p. 357
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Mountaintop Coal Mining in West Virginia, U.S.
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Mining has harmful effects.

• Scarring and disruption of the land surface
• E.g., spoils banks
• Loss of rivers and streams 1900 km have been
  buried
• Subsidence collapse of land

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Mining Has Harmful Environmental Effects

• Major pollution of water and air toxin-laced
  mining waste deposited in areas other than mining
  site . Acid Mine Drainage
• Effect on aquatic life ph change,40 of all US
  watersheds contaminated
• Large amounts of solid waste
• 3/4th of all US solid waste
• mining gold

Illegal Gold Mine
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Removing Metals from Ores Has Harmful
Environmental Effects

• Ore extracted by mining
• Ore mineral desired metal
• Gangue waste material. Removing the gangue from
  the ores produces tailings, Particles of toxic
  metals blown by the wind or leached by rainfall
  can contaminate surface water and groundwater.
• Smelting heating ores to release metals.
• Without proper equipment, releases sulfur dioxide
  and suspended particles, damage vegetation and
  acidify soils
• Water pollution highly toxic cyanide salts to
  extract gold from its ore. Leave behind cyanide
  laden water
• Summitville Gold Mining, Co

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Summitville Gold Mining Site in Colorado, U.S.
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Ecological Restoration of a Mining Site in New
Jersey, U.S.
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How Long Will Supplies of Nonrenewable Mineral
Resources Last?

• All nonrenewable mineral resources exist in
  finite amounts, and as we get closer to depleting
  any mineral resource, the environmental impacts
  of extracting it generally become more harmful.
• Relatively abundant deposits of iron and aluminum
  (bauxite)
• Scarce manganese,chromium,cobalt,platinum
• An increase in the price of a scarce mineral
  resource can lead to increased supplies and more
  efficient use of the mineral, but there are
  limits to this effect.

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Uneven distribution of minerals

• Most of the nonrenewable mineral resources
  supplied by
• Canada
• United States
• Germany
• Russia
• South Africa self sufficient in all key
  minerals, largest producer of gold, chromium and
  platinum
• Australia

8 of world population, consume 75 of the
worlds key metals China increasing consumption
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Four Strategic metal resources.

• Manganese
• Cobalt
• Chromium
• Platinum
• US has little or no reserves of these metals
  which are essential for the countrys economy and
  military strength
• May ave to switch to nano materials

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The Nanotechnology Revolution

• Nanotechnology, tiny tech use carbon, oxygen
  and silicone atoms to create everything from
  medicines,solar cells to automobile bodies
• Currently used in more than 400 items odor
  eating socks, wrinkle free clothes, cosmetics,
  sun screens
• Nanoparticles
• Are they safe?
• Investigate potential ecological, economic,
  health, and societal risks
• Develop guidelines for their use until more is
  known about them

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Economic Depletion of non renewable mineral
resources

• Future supply depends on
• Actual or potential supply of the mineral
• Rate at which it is used
• When it becomes economically depleted
• Recycle or reuse existing supplies
• Waste less
• Use less
• Find a substitute
• Do without

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Depletion Curves for a Nonrenewable Resource
Depletion time time it takes to use up
approximately 80 of the reserves of a mineral at
a given rate of use
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Market Prices Affect Supplies of Nonrenewable
Minerals

• Subsidies and tax breaks to mining companies keep
  mineral prices artificially low
• Does this promote economic growth and national
  security?
• Scarce investment capital hinders the development
  of new supplies of mineral resources

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The U.S. General Mining Law of 1872

• Encouraged mineral exploration and mining of
  hard-rock minerals on U.S. public lands
• Developed to encourage settling the West (1800s)
• Until 1995, land could be bought for 1872 prices
• Companies must pay for clean-up now

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Is Mining Lower-Grade Ores the answer?

• Factors limit the mining of lower grade ores
• increased cost of mining
• limited availability of fresh water , specially
  in arid areas
• environmental impacts of increased land
  disruption, waste material and pollution produced
  during mining and processing
• Use microorganisms that can extract minerals
  in-place or in-situmining.
• Biomining genetic engineering techniques used
  to produce bacteria that can be used to extract a
  particular metal without disturbing the
  surrounding environment

48
Extend Supplies by Getting More Minerals from
the Ocean

• Mineral resources dissolved in the ocean-very low
  concentrations, requires more energy and money
  than they are worth
• Only magnesium, bromine and sodium chloride are
  abundant enough to be extracted profitably
• Deposits of minerals in sediments along the
  shallow continental shelf and near shorelines
  sand, gravel,phosphates,sulfur,tin.copper,iron,tun
  gsten,silver,titanium,platinum,diamonds

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Extend Supplies by Getting More Minerals from the
Ocean

• Hydrothermal ore deposits sulfides, zinc,
  silver, copper precipitate out and build up as
  mineral deposits
• currently costs too much to extract,
• disputes over ownership
• Metals from the ocean floor potato sized
  manganese nodules, that cover 25-50 of the
  Pacific ocean floor
• Effect of mining on aquatic life
• Environmental impact sea bed mining ,less
  impact than land (??)

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How Can We Use Mineral Resources More
Sustainability?

• Find substitutes for some scarce mineral
  resources
• materials revolution silicon, ceramics,
  plastics
• houses made of styroform sprayed with ceramic
  spray called Grancrete, reduces use of timber
• high strength plastics and composite materials
  strengthened by light weight carbon and glass
  fibers are transforming the automobile and
  aerospace industries
• making plastics requires fossil fuels and oil
• Substitution may not always be possible
• platinum, industrial catalyst
• chromium stainless steel

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We Can Recycle and Reuse Valuable Metals

• Recycling
• Lower environmental impact than mining and
  processing metals from ores
• Reuse gold, silver, iron, copper, steel,
  aluminum, platinum
• Recycling aluminum beverage cans and scrap
  aluminum produces 95 less air pollution, 97
  less water pollution and uses 95 less energy

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There Are Many Ways to Use Mineral Resources More
Sustainability

• How can we decrease our use and waste of mineral
  resources?
• Pollution and waste prevention programs
• 3M Pollution Prevention Pays (3P)
• Cleaner production air pollution 70 lower,
  saved 750 million in waste disposal and material
  costs

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Sustainable Use of Nonrenewable Minerals
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Industrial Ecosystems Copying Nature

• Mimic nature recycle and reuse most minerals and
  chemicals waste outputs of one organism becomes
  the nutrient inputs of another
• Resource exchange webs wastes of one
  manufacturer becomes the raw materials for
  another
• Ecoindustrial parks on brownfields, which are
  abandoned industrial sites
• Industrial forms of biomimicry
• Benefits come up with new environmentally
  beneficial and less resource-intensive chemicals
• Better image among consumers

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An Industrial Ecosystem in Denmark Mimics Natural
Food Web