27.1 Importance of minerals to society

Document Sample
27.1 Importance of minerals to society Powered By Docstoc
					  Chapter 27

Minerals and the
    How Mineral Deposits Are
• Ore Deposits – formed when metals are
  concentrated in anomalously high
  amounts by geological processes
• Mineral resources are usually extracted
  from ore deposits
     Resources and Reserves
• Minerals are classified as:
  – 1. Mineral Resources
     • Elements, chemical compounds, minerals or rocks
       that can be extracted to obtain a usable commodity
  – 1. Mineral Reserves
     • The portion of the resource that is identified and
       from which usable materials can be legally and
       economically extracted at the time of evaluation
       Availability of Mineral
• When the availability of a mineral
  becomes limited, there are 4 possible
  1. Find more sources
  2. Recycle and reuse what has already
  been obtained
  3. Reduce consumption
  4. Find a substitute
Impacts of Mineral Development
• Environmental Impacts
  – Depends on many factors – mining
    procedures, climate, rock type, etc.
• Social Impacts
  – Increased demand for housing and services in
    mining areas
  Minimizing Environmental
Impact of Mineral Development
• Environmental regulations at the federal,
  state and local levels
• On-site and off-site treatment of waste
• Practicing the 3 R’s of waste management
   Minerals and Sustainability
• R-to-C Ratio
  – A measure of the time available for finding the
    solutions to depletion of nonrenewable
  – R = known reserves
  – C = rate of consumption
Student Presentations
                 27.1: Importance of minerals to society

•   Many mineral products found in typical
    American homes
•   Dishes from clay, glasses from sand,
    stainless steel utensils from
    processing iron ore and other
    minerals, copper in electrical wiring
•   Standard of living increases with
    availability of minerals in useful forms
•   To maintain standard of living in U.S.,
    every person requires about 10 tons of
    nontuel minerals per year
•   Minerals replenish too slowly to be
    considered a renewable resource, so

    they must be conserved
          27.2 How mineral deposits are formed

• Ore deposits=metals that are
  concentrated in anomalously
  high amounts by geological
• Origin and distribution of
  mineral resources is intimately
  related to the history of the
  biosphere and to the entire
  geological process
• 6 processes of formation of
  mineral deposits= plate
  boundaries, igneous,
  sedimentary, biological, and
    Distribution of Mineral Resources
•   Earth’s crust is made up of
    silica, oxygen and other
•   9 elements account for 99% of
    the crust’s weight:
     – Oxygen- 45.2%
     – Silicon- 27.2%
     – Aluminum- 8%
     – Iron- 5.8%
     – Calcium- 5.1%
     – Magnesium- 2.8%
     – Sodium- 2.3%
     – Potassium- 1.7%
     – Titanium- 0.9%

    Distribution of Mineral Resources
                                                 • Deposits occur due to
•   Ocean water contains about 3.5%
    dissolved solids                               gravitational attraction bringing
      – Elements are transported into the          together dispersed matter,
          ocean by weathered rocks, wind or        which is condensed and
•   Each cubic kilometer contains 2 metric
                                                   heated in the process, where
    tons of zinc and copper, .8 metric tons of     the heat is sufficient to produce
    tin, 0 .3 of silver, 0.1 of gold               molten liquid core, which sank
•   Once the crustal ore deposits are              towards the Earth. Crust forms
    depleted, it will be more effective to
    extract metals from rocks, or lower grade      from lighter elements, and the
    deposits.                                      heavier metals sank.

                                                 • The elements are not evenly
                                                   distributed due to geologic and
                                                   biologic procceses.
          Igneous Processes
• Ore deposits may form when magma cools.
• As molten rock cools, heavier minerals that
  crystallize early may slowly sink or settle toward
  the bottom of the magma.
• Whereas lighter minerals that crystallize later are
  left at the top.
• Ex) Chromite.
• When magma contains small amounts of carbon
  and is deeply buried and subjected to very high
  pressure during cooling, diamonds may form.
Igneous Processes continued…
• Hot waters moving within
  the crust are perhaps the
  source of most ore
• Circulating groundwater
  is heated and filled with
  minerals on contact with
  deeply buried rocks, and
  this water then moves up        3350995143/
  to other, cooler rocks,
  where the cooled water
  deposits the dissolved
                     Plate boundaries

•   Plate tectonics responsible for
    formation of some mineral
•   Divergent plates
     – Cold ocean water comes in
       contact with hot molten rock,
       heated water is light and
       chemically active, rises through
       fractured rocks and leaches
       metals, metals are carried through
       solution and deposited as metal
       sulfides when water cools
•   Convergent plates
     – Rocks saturated with seawater
       are forced together, heated, and
       subjected to intense pressure,
       which causes partial melting,
       which mobilizes metals in the
       molten rock, or magma
         Sedimentary Processes
• Sedimentary processes are the transport of sediments by
  wind, water, and glaciers
• Water and wind segregate the sediments by size shape and
   – EX: beach sand vs gravel
• Placer deposits – Deposits of heavy metals in slow waters
• evaporates - Lakes that evaporate and leave mineral
  deposits after being isolated by geologic activity, or climatic
   – Marine evaporates (solids)
   – Nonmarine evaporates (solids)
   – Brines (liquids derived from wells, thermal springs, inland
     lakes and seawaters)
       Biological Processes
• Ex) Phosphates and Iron ore deposits.
• Several types of Iron ore deposits:
  -Gray beds: contain unoxidized iron.
  Formed when there was little oxygen in
  the atmosphere.
  -Red beds: contain oxidized iron. Formed
  when there was relatively more oxygen.
            Biological Processes
• It appears that major deposits
  of iron stopped forming when
  the atmospheric concentration
  of oxygen reached it’s present
• Organisms are able to form
  many kinds of minerals.
• Some minerals cannot be
  formed inorganically in the
• 31 different biologically            66584949/sizes/l/
  produced minerals.
• Biologically produced minerals
  contribute significantly to
  sedimentary deposits.
Weathering Processes creates mineral deposits in
                        two ways:

•   Residual Deposits can develop where soluble
    substances are removed, leaving behind more
    valuable mineral resources by residual

•   Enrichment of low-grade deposits Downward
    infiltration of acid, metal-rich solutions can cause
    deposition of oxidized ores above the water table
    and small zones of sulfide enrichment below the
    water table.
    27.3 Resources and Reserves

     Resources and Reserves
• Minerals can be classified as resources or
• Mineral resources: elements, chemical
  compounds, minerals, or rocks concentrated in a
  form that can be extracted to obtain a useable
  – Can be bought and sold
• Reserves: known and identified deposits of earth
  materials from which useful materials can be
  extracted profitably with existing technology and
  under present economic and legal condtitions
• Classification of whether a mineral deposit
  is part of the resource or as a reserve may
  be question of economics
  – Scarcity and price
• Resources > Reserves
• It is important for planning purposes to
  estimate future resources
  – Continual reassessment of all components of
    a total resource through consideration of new
  – the probability of geologic discovery
  – shifts in economic and political condition
27.4 Classification, Availability, and Use of
  Mineral Resources
a. Earth’s Mineral Categories
    1. Elements for metal production and technology
    2. Building Materials
    3. Minerals for the chemical industry
     4. Minerals for agriculture
  b. Metallic Mineral Categories
    Abundant Metals          Scarce Minerals
       Iron                  Copper
       Aluminum              Lead
       Chromium              Zinc
       Manganese             Tin
       Titanium              Gold
       Magnesium             Silver
                           Rate of Use
Sodium and iron
•100-1,000 million metric tons per year
Nitrogen, Sulfur, Potassium, and Calcium
•10-100 million metric tons per year
Zinc, Copper, Aluminum, and Lead
•3-10 million metric tons per year
Gold and Silver
•10,000 or less metric tons per year

  Iron makes up 95% of all metals consumed
Availability of Mineral Resources
Big Mining Issue= $$cost$$
Problem is when the costs of mining exceed worth of material

4 Solutions
1.Find more sources
2.Recycle and reuse what has already
  been obtained
3.Reduce consumption
4.Find a substitute
Mineral Resources are Limited

How long will the resources last?

What will the environmental effects be?
Short-term? Long-term?

How can we best use the resources that
are available?
                                     Mineral Consumption
Botkin & Keller, Sixth Edition Environmental Science:
Earth as a Living Planet, figure 27.4 pg 594

• Rapid consumption
• Consumption with conservation
• Consumption and conservation with recycling

• Rapid consumption has dominated most resource utilization
• Increased conservation and recycling are expected as supply of
  resources becomes short
• Trend for recycling well established for metals, such as copper, lead,
  and aluminum
• From global viewpoint: limits on mineral resources and reserves threaten
  our affluence
• Demand for mineral resources expands at faster and faster rate as world
  population and desire for higher standard of living increase
• More developed countries consume disproportionate amount of mineral
  resources extracted

• United States, Western Europe, Japan collectively use most of aluminum,
  copper, and nickel extracted from the earth
• Rate of production of these metals will have to increase by several times if
  world per-capita consumption rate is to rise to level of consumption in
  developed countries today

                 U.S. Supply of Mineral Resources

• United States imports many of the minerals needed for its complex
  military and industrial system (strategic minerals)
   – Examples: bauxite, manganese, graphite, cobalt, strontium,
• Possibility: supply may be interrupted by political, economic, military
  instability in supplying nation
• Dependence on other countries’ imported minerals does not mean
  that the minerals do not exist in the country in quantities that cannot
  be mined; suggests that there are economic, political, or
  environmental reasons that make it easier, more practical, or more
  desirable to import material
• Situation results in political alliances that would be otherwise
                  Impacts of Mineral Development
                 Minimizing Environmental Impact of
                        Mineral Development

         27.5 Impacts of Mineral
• Impact of exploitation on the environment
   depends on factors of:
    – Ore quality, mining procedures, local
      hydrologic conditions, climate, rock types,
      size of operation, topography, and many
      more factors
• Mining and the processing of mineral
   resources generally have a considerable
   impact on land, water, air, and biological
• Subsurface mines are much
smaller than open-pit mines
• Surface mining is a lot cheaper
but have way more environmental

   More info
• Surface mines and quarries cover less than
  .5% of the total area of the US
• A big problem that is associated with mineral
  resource development is the release of
  harmful trace elements into the environment
   – Some trace elements could be cadmium, cobalt,
     copper, lead, molybdenum, and others
• Some social impacts are the rapid influx of
   workers into areas where they are not
   prepared for growth
• Mining costs have spiked
because of the environmental
regulations for the mining

Minimizing Environmental Impact
    of Mineral Development
              Waste Pollution
• The major
  environmental impacts
  of mineral resource
  utilization are
  somehow related to
  waste products.
• The waste leads to
  pollution that may be
  toxic to humans,
  harmful to
  ecosystems, and have
  negative aesthetic

                                    A Closer Look
• The Butchart Garden formally began as a
  lime stone quarry and then was
  transformed by mining reclamation
•   Picture:
  Environmental Effects Associated with Mining

• Minimization of environmental effects associated
  with mining:
  – Reclaim areas where disturbance has occurred
  – Stabilizing and removing contaminated soils
  – Controlling air emissions metals and other materials
  – Preventing contaminated water from leaving or
    treating contaminated water that already left
  – Treating waste on and off site
  – Practicing the three R’s of waste management
      • Recycle Reduce Reuse
                    The Three R’s
• The value of all
  recycled material is
  about $50 Billion
   – 90% by weight are iron
     and steel
   – Three reasons to recycle
     iron and steel:
      • Processing idustry and
        large scrap collection is
      • Economic burden
        would result in failure to
      • It would create
        environmental impacts
        related to the disposal
        of over 50 million tons
     Minerals and Sustainability
• There are solutions to
  development that
• There are alternative
  ways to use the
  minerals and replace
  those minerals with
  other types of
   – i.e. copper can be
     replaced in telephone
     wires with glass cables
              R-to-C Ratio
• R-to-C Ratio- measure of time
  available for finding solutions to the
  depletion of nonrenewable reserves.
• Provides a view of the scarcity of a
  particular mineral resource.
Minerals and Sustainability

         By Ross Colburn
   Designed by Ashley Murray
  Pictures found by Chaz Schied
   Minerals and Sustainability
• In mineral sustainability, it isn’t the
  minerals we use but what we use that
  leads to the diminishment of resources.
• Ex: Fiberglass wires
• Digital cameras
• Eiffel Tower could have used 1/4 of the
  total steel used.
             R-to-C Ratio
• The ratio of reserve to consumption
• How much of a mineral we have compared
  to how much we use.
• The ratio provides the view of the scarcity
  of a mineral.
• Ex: The R-to-C Ratios of zinc and copper
  have fluctuated in the last thirty years.
          Ways to Sustain
• Finding ways to more wisely use
• Developing more efficient mining
• More efficiently using resources
• Recycling
• Finding substitutes for the nonrenewable
  resources to accomplish the same tasks.
• Fiberglass sleeving,fiberglass sleeving manufacturer,fiberglass
  sleeving exporter,suppliers,India. IMPEX INSULATION PVT. LTD.
  09 Apr. 2009 <>.
• Eiffel Tower Paris France." Washington DC. 09 Apr.
  2009 <>.
Coal Mining

      Chelsea Barroero
        Justin Haley
       Maile Hoffmann
  Strip Mining
 Over half the
  mining done in the
  U.S. is strip mining
 Has the potential to
  pollute or damage
  water, land, and

Underground mining

  Account for
   approximately 40%
   of mines in the U.S.
  Underground mining
   is dangerous
    Risk of collapse,
     explosion, or fire,
     respiratory illness
Environmental effects of
underground mining
  Acid mine drainage from
   mines and waste piles
   has polluted thousands
   of kilometers of streams.
  Land subsidence can
   occur over mines
  Coal fires are issues and
   can cause belch smoke
   and hazardous fumes
The future of coal
  Coal currently produces
   60% of the electricity
   and 25% of the total
   energy consumed in the
  Regulations will be set to
   prevent emissions of
   fumes caused by coal