Minerals and Rock Resources

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Minerals and Rock Resources

• Chapter 12

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Figure 12.2 - Pegmatite
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Resources--General Definition

• All things necessary to human life and
  civilization that have some value to individuals
  and/or society
• What are some resources weve already studied?
• Renewable
• Replaceable on a human time scale

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Resources reserves

• 1) Reserves
• The quantity of a given material that has been
  discovered and can be legally and economically
  extracted with existing technology.
• A conservative estimate
• 2) Subeconomic reserves (conditional reserves)
• Deposits already found but cannot be legally or
  economically extracted with existing technology
• 3) Speculative resources
• Undiscovered resources that are expected to be
  found

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Projections about resource availability and price
depend on

• Projections of future supply
• Size of reserves
• International politics
• Projections of future demand
• Population, standard of living, technology
• Projections of future cost of extraction
• Including environmental costs

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• Ore
• Rock in which a valuable or useful metal occurs
  at a concentration sufficiently high to make it
  economically worth mining.
• Concentration factor
• (Conc. in ore)/(conc. in average cont. crust)
• Ores are unusual rocks with an uneven worldwide
  distribution

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Examples of Metals obtained from Ores

• Aluminum or Iron appliances and vehicles
• Metals for conductors or semi-conductors
• Gems, gold, and silver jewelry
• Lead from galena
• Copper from malachite and azurite
• Zinc from sphalerite
• Many other metals found in rocks

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Figure 12.1 US is a major consumer
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Distribution

• Globally, very un-even distribution
• Some countries have plenty export nations
• Some countries have none import nations
• Figure 12.1
• Un-even distribution is reason wars are fought

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Mineral-rich countries

• Cuba
• 40 of nickel
• Chile
• 30 of copper
• South Africa
• 50 gold
• 75 chromium
• 90 platinum
• diamonds

• US
• 50 of molybdenum
• Australia New Guinea
• 50 of aluminum ore
• Zaire
• 50 of cobalt

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Types of Mineral Deposits

• Igneous Rocks and Magmatic Deposits
• Pegmatite
• Kimberlite
• Hydrothermal Ores
• hydrothermal
• Relationship to Plate Margins
• Sedimentary Deposits
• Banded iron formation
• Evaporite
• Other low-temperature ore-forming processes
• Placers
• Metamorphic Deposits

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Figure 12.3
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Figures 12.4 a, b, and c Hydrothermal Ore
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Figure 12.5
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Figures 12.7 a and b
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Figure 12.10 a and b
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Mineral and Rock ResourcesExamples (the ways we
use)

• Metals iron, aluminum, copper, lead, zinc,
  nickel, cobalt, gold, silver, or platinum
• Nonmetallic Minerals sulfides, lime (calcium
  carbonate), sulfur, halite, clay, gypsum, or
  potash
• Rock resources most abundant quantity of earth
  resources we use
• Sand, gravel, limestone, quartz-rich sand,
  marble, granite, and sandstone

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Figure 12.11 US per capita consumption
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Figure 12.12
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Mineral Supply and Demand

• Global demand is always growing
• About 2 pre-World War II
• About 10 World War II to mid-1970s
• Demand is fluctuating now
• U.S. Mineral Production and Consumption
• See Figure 12.11, Table 12.1, and Figure 12.13
• U.S. population is only 4.5 of the world but
  consumes many times its share of the world supply

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Table 12.1
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Figure 12.13US Consumption of World Production
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World Mineral Supply

• World demand is always fluctuating
• Commodities do not follow fluctuating trends
• Mineral reserves eventually will be depleted
• Import/export relationships will fluctuate
• Technology often allows more access to difficult
  or low grade ore deposits
• Future mineral-resource shortages will occur and
  cause international tension

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Figure 12.14
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Table 12.2
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Minerals for the FutureSome Options Considered

• Consider controlling consumption rates
• Reduce the consumption rates
• Hold these rates steady
• Carefully consider the facts
• Globally the less developed nations are striving
  to achieve comparable standards of living as the
  technologically advanced countries enjoy
• Countries that have the fastest-growing
  populations are not well endowed with mineral
  deposits and are the less developed countries of
  the world!

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Table 12.3
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Figure 12.15
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New Methods in Mineral Exploration

• Fact the economically easy and profitable
  deposits are being depleted
• Geophysics is a useful aid to locating new
  deposits
• Gravity survey
• Magnetic survey
• Electrical property survey
• Geochemical survey and prospecting is an
  increasingly popular exploration tool
• Remote sensing is expanding into exploration
  strategies

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Figure 12.16
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Remote Sensing

• Sophisticated but valuable exploration tools
• Useful to detect, record, and analyze energy
  emitted off the earth
• Aerial photography
• Satellites
• Space shuttle, and other manned missions
• Remote sensing is backed up by ground truth
  activities
• old fashioned geologic mapping
• Advances in the geological sciences are directed
  toward integration of remote sensing,
  geochemistry, and geophysics

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Figures 12.17 a and b Landsat Images South
Africa Dry and Wet Seasons
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Figure 12.18
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Marine Mineral Resources

• Oceans our new mineral frontier
• Sea water contains abundant dissolved minerals
  and many useful element
• Most extraction techniques currently used are
  energy intensive and expensive
• Hydrothermal ore deposits along seafloor
  spreading ridges are a possible source of many
  materials
• Currently, they are too deep - of limited benefit
• Manganese nodules are widely distributed on the
  ocean floors a promising solution.
• Many political, environmental, and legal
  obstacles must be over come before they can be
  mined

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Figure 12.20 b
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Conservation of Mineral Resources

• Overall need for resources is growing must
  reduce this expansion
• Some mineral resources maybe substituted by
  other, more abundant resources
• Plastics replacing automobile parts
• Recycling many metals are successfully recycled
• More recycling is required
• Not all commodities are easy to recycle
• Measures to reduce demand must be the key

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Table 12.4
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Impacts of Mining Activities

• Very stressful to the environment
• Must be carefully planned
• Must be safe to miners and their neighbors
• Must be contained water and air pollution is a
  major problem

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Figure 12.22
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Underground Mines

• Generally hard to see where they are located
• Area of disturbance is local
• Miners place the tunnels close to the ore body to
  cut down on waste
• Once mines are closed they can be sealed with the
  non-ore rock (waste rock)
• Surface collapse general limited and controllable
  with modern mine reclamation practices
• Old, abandoned, and forgotten mines are still a
  problem

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Figure 12.23 a
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Figure 12.23 b
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Surface Mines

• Open-pit
• Mine a large ore body located near the surface
• Permanent changes to local topography will occur
• Strip mining
• Most ores occur in a layer that generally is
  parallel to the surface
• The ore zone is overlain by vegetation, soil,
  non-ore rock that must be removed
• Spoils banks are designed to collect the waste
  rock
• Current reclamation law requires that it be
  return to the pit and the original soil replaced
• Expensive but vital

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Figure 12.24 a
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Figure 12.24 b
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Figure 12.25 a
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Figure 12.25 b
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Figure 12.25 c
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Figure 12.25 d
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Mineral Processing

• Mineral extraction is environmental hazardous
• Ore rock is ground or crushed for extraction
• The fine waste material is placed in tailings
• The tailings are exposed to wind and weather
• Harmful elements such as mercury, arsenic,
  cadmium, or uranium can leached out
• The surface and subsurface water systems are too
  often contaminated
• Chemicals used in ore extraction must be
  controlled and not just dumped
• Smelting ores to extract metals, often produce
  metal laden exhaust gas or ash, sulfur oxide and
  acid rain pollution

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Figure 12.26 a
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Figure 12.26 b