Minerals and the Environment

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Chapter 27

• Minerals and the Environment

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How Mineral Deposits Are Formed

• Ore Deposits formed when metals are
  concentrated in anomalously high amounts by
  geological processes
• Mineral resources are usually extracted from ore
  deposits

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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

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Availability of Mineral Resources

• When the availability of a mineral becomes
  limited, there are 4 possible solutions
• 1. Find more sources
• 2. Recycle and reuse what has already been
  obtained
• 3. Reduce consumption
• 4. Find a substitute

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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

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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 Rs of waste management

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Minerals and Sustainability

• R-to-C Ratio
• A measure of the time available for finding the
  solutions to depletion of nonrenewable resources
• R known reserves
• C rate of consumption

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Student Presentations
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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

http//www.glowinthedark.net.au/images/800pxFluore
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27.2 How mineral deposits are formed
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• Ore depositsmetals that are concentrated in
  anomalously high amounts by geological processes
• 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 weathering

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Distribution of Mineral Resources

• Earths crust is made up of silica, oxygen and
  other elements
• 9 elements account for 99 of the crusts 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

www.eatgallery.com/upload_files/image/crystal
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Distribution of Mineral Resources Cont.

• Ocean water contains about 3.5 dissolved solids
• Elements are transported into the ocean by
  weathered rocks, wind or glaciers
• Each cubic kilometer contains 2 metric tons of
  zinc and copper, .8 metric tons of tin, 0 .3 of
  silver, 0.1 of gold
• Once the crustal ore deposits are depleted, it
  will be more effective to extract metals from
  rocks, or lower grade deposits.

• Deposits occur due to gravitational attraction
  bringing together dispersed matter, which is
  condensed and heated in the process, where the
  heat is sufficient to produce molten liquid core,
  which sank towards the Earth. Crust forms from
  lighter elements, and the heavier metals sank.
• The elements are not evenly distributed due to
  geologic and biologic procceses.

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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.

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Igneous Processes continued

• Hot waters moving within the crust are perhaps
  the source of most ore deposits.
• Circulating groundwater is heated and filled with
  minerals on contact with deeply buried rocks, and
  this water then moves up to other, cooler rocks,
  where the cooled water deposits the dissolved
  minerals.

• http//www.flickr.com/photos/9099757_at_N05/335099514
  3/

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Plate boundaries

• Plate tectonics responsible for formation of some
  mineral deposits
• 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

http//www.rubyfalls.com/images/plate_tectonics_01
.jpg
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Sedimentary Processes

• Sedimentary processes are the transport of
  sediments by wind, water, and glaciers
• Water and wind segregate the sediments by size
  shape and density
• 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 variations.
• Marine evaporates (solids)
• Nonmarine evaporates (solids)
• Brines (liquids derived from wells, thermal
  springs, inland lakes and seawaters)

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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.

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Biological Processes

• It appears that major deposits of iron stopped
  forming when the atmospheric concentration of
  oxygen reached its present level.
• Organisms are able to form many kinds of
  minerals.
• Some minerals cannot be formed inorganically in
  the biosphere.
• 31 different biologically produced minerals.
• Biologically produced minerals contribute
  significantly to sedimentary deposits.

• http//www.flickr.com/photos/davidaporter/20665849
  49/sizes/l/

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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
  concentration.
• 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.

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Enrichment
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27.3 Resources and Reserves

• http//beatrees.com/Crystal_cluster.jpg

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Resources and Reserves

• Minerals can be classified as resources or
  reserves
• Mineral resources elements, chemical compounds,
  minerals, or rocks concentrated in a form that
  can be extracted to obtain a useable commodity
• 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

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• Classification of whether a mineral deposit is
  part of the resource or as a reserve may be
  question of economics
• Scarcity and price
• RESOURCES ARE NOT RESERVES!!
• Resources gt Reserves

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• It is important for planning purposes to estimate
  future resources
• Continual reassessment of all components of a
  total resource through consideration of new
  technology
• the probability of geologic discovery
• shifts in economic and political condition

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• 27.4 Classification, Availability, and Use of
  Mineral Resources
• Earths Mineral Categories
• Elements for metal production and technology
• Building Materials
• Minerals for the chemical industry
• Minerals for agriculture

b. Metallic Mineral Categories
Abundant Metals Iron Aluminum Chromium Manganese
Titanium Magnesium
Scarce Minerals Copper Lead Zinc Tin Gold Silver
Platinum Uranium Mercury molybdenum
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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
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Availability of Mineral Resources
Big Mining Issue cost Problem is when the
costs of mining exceed worth of material

• 4 Solutions
• Find more sources
• Recycle and reuse what has already been obtained
• Reduce consumption
• Find a substitute

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Mineral Resources are Limited
Questions??? 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?
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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

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• 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
• IMPOSSIBLE IN LONG RUN TO SUPPORT EVER-INCREASING
  POPULATION ON FINITE RESOURCE BASE.

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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, asbestos
• 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 unlikely

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• 595-596
• Impacts of Mineral Development
• 597-599
• Minimizing Environmental Impact of Mineral
  Development

27.5-27.6
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27.5 Impacts of Mineral Development

• 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 resources
• Subsurface mines are much
• smaller than open-pit mines
• Surface mining is a lot cheaper
• but have way more environmental
• effects

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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
• industry

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erals.jpg
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Minimizing Environmental Impact of Mineral
Development
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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 consequences.

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A Closer Look

• The Butchart Garden formally began as a lime
  stone quarry and then was transformed by mining
  reclamation
• Picture http//www.destination360.com/north-ameri
  ca/canada/butchart-gardens.php

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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 Rs of waste management
• Recycle Reduce Reuse

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The Three Rs

• 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
  huge
• Economic burden would result in failure to
  recycle
• It would create significant environmental impacts
  related to the disposal of over 50 million tons

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y_Melting_Scrap_Steel_.jpg
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Minerals and Sustainability

• There are solutions to sustainable development
  that incorporate nonrenewable resources
• There are alternative ways to use the minerals
  and replace those minerals with other types of
  technology
• i.e. copper can be replaced in telephone wires
  with glass cables

http//www.molam.net/images/CopperWire.jpg
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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.

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Minerals and Sustainability

• By Ross Colburn
• Designed by Ashley Murray
• Pictures found by Chaz Schied

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Minerals and Sustainability

• In mineral sustainability, it isnt 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.

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Examples
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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.

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Ways to Sustain

• Finding ways to more wisely use resources
• Developing more efficient mining techniques
• More efficiently using resources
• Recycling
• Finding substitutes for the nonrenewable
  resources to accomplish the same tasks.

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Credits

• Fiberglass sleeving,fiberglass sleeving
  manufacturer,fiberglass sleeving
  exporter,suppliers,India. IMPEX INSULATION PVT.
  LTD. 09 Apr. 2009 lthttp//impexinsulation.tradeind
  ia.com/gt.
• Eiffel Tower Paris France." Washington DC.
  VisitingDC.com. 09 Apr. 2009 lthttp//www.visitingd
  c.com/paris/eiffel-tower-paris-france.aspgt.

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Coal Mining

• Chelsea Barroero
• Justin Haley
• Maile Hoffmann

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Strip Mining

• Over half the mining done in the U.S. is strip
  mining
• Has the potential to pollute or damage water,
  land, and biological resources.

Pollutionissues.com
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Underground mining

• Account for approximately 40 of mines in the
  U.S.
• Underground mining is dangerous
• Risk of collapse, explosion, or fire, respiratory
  illness

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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

cdc.gov
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The future of coal

• Coal currently produces 60 of the electricity
  and 25 of the total energy consumed in the U.S.
• Regulations will be set to prevent emissions of
  fumes caused by coal mining