Post on 16-Oct-2021
February 03, 2014
Chapter 15: Geology and Nonrenewable Mineral Resources
What is a nonrenewable resource?
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The Earth: Core, Mantle, CrustTectonic Plates: Lithosphere Surfing
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3 types of plate boundaries:
1. Convergent plate boundary> oceanic-continental: subduction zone and
trench> continental-continental: mountain ranges
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3 types of plate boundaries:
2. divergent plate boundary> oceanic ridge
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3 types of plate boundaries:
3. Transform fault> plates slide past one another> CA San Andreas fault
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Earthquakes, volcanoes, and tsunamis (Read Supplement 11 for more info)
Earthquakes• Richter scale• Recent earthquakes: 2010 Haiti, 2005 Kashmir
(Pakistan)
Volcanoes• found at subduction zones or hot spots
Tsunamis• Giant sea swells• Recent tsunamis: 2004 Indonesia, 2011 Japan
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Tectonic plates recycles Earth's crust over geological time• mineral deposits• evolution
Other processes:• volcanic eruptions play role in forming atmosphere
and climate, rocks and lava become rich soil• Tsunamis leave rich sediment
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External processes (sun and gravity)• Wear down Earth's surface and produce
landforms• Weathering
> Physical/mechanical– Frost wedging
> chemical weathering> biological weathering
http://education.fcps.org/outdoorschoolfcps/frostwedging
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External processes (sun and gravity)• Wear down Earth's surface and produce
landforms• Erosion
> streams> rain> wind> Glaciers> *Human activity
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External processes (sun and gravity)• Wear down Earth's surface and produce
landforms• Mass wasting
> Rockslides> landslides> mudflows
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Resources in the Earth's Crust
Mineral resource: concentration of naturally occurring material in/on the earth's crust that can be • extracted• processed into useful material• affordable cost• Examples: fossil fuels, metallic minerals,
nonmetallic minerals
Ore: Rock that contains enough minerals to mine
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(Pro
fitab
le)
*Increases with new discovery, new technology
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Distribution of mineral resources are not even• US, Canada, Russia, South Africa, and Australia
supply most nonrenewable resources• US, Germany, Russia consume 75% metals• *Economies rely on imports
*Stability of source country can affect supply and practices
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Strategic metal resource: Manganese, cobalt, chromium, platinum
Manganese: Steel production,
Cobalt: Superalloys for jet aircraft engines
Chromium: stainless steel
Platinum: Catalytic converter, emission control
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Rock cycle recycles earth's rocks and concentrates mineral resources.
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Mining, processing, and using mineral resources takes lots of energy, causes land disturbance, soil erosion, and air and water pollution.
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Mining
1. Surface mining
2. Subsurface mining
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Surface Mining: Shallow deposits
• Mechanized equipment removes overburden (soil and rock = spoils)
• 90% nonfuel mineral and rock resources• 60% coal
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Surface Mining
Type of resource and topography determines strategy
• Open-pit mining• Strip-mining (horizontal beds)• Area strip mining (flat terrain)
> Dig trench> Strip mineral> Fill trench with overburden> *Leaves spoil banks
– highly erodible– *Susceptible to chemical weathering and
erosion– *Restoration difficult (no top soil)
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Surface Mining
Type of resource and topography determines strategy
• Contour strip mining (hill or mountains)> terraces> *Coal in Appalachia> highwall: highly erodible bank of soil and rock
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Surface Mining
Type of resource and topography determines strategy
• Mountaintop removal> rock/dirt dumped into streams and rivers> increase flood hazards> toxic wastewater
http://en.wikipedia.org/wiki/File:Martin_County_home.jpg
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Subsurface mining: too deep for surface mining
• Dig vertical shaft + tunnels to reach deposits> disturbs less land> less waste> more dangerous and expensive
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Surface Mining Control and Reclamation Act of 1977
• Requires mining companies to restore most surface mined land
• Unsuccessful, takes a long time• arid areas --> deserts• *coal companies and lobbying
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Mining Impacts• Scarring and disruption of land surface
> $70 billion in cleanup• Subsidence• Pollution
> 5.5 metric tons of mining solid waste for 2 gold wedding rings
> toxins in mining waste (erosion)> acid mine drainage (rain carries sulfuric acid)> mercury, arsenic
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Removing Metals from Ores
Ore ore mineral + gangue
tailings-can contaminate surface water and groundwater
Smelting: roast ore to release metals• Emit air pollutants: sulfur dioxide,
particles
Cyanide heap extraction: Cheap, for gold• Cyanide is toxic• leave behind cyanide-laden water in
leaking holding tanks
http://maharlikafilms.com/blog/
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Supplies of Mineral Resources
Future supply depends on 2 things:• actual or potential supply• rate of use
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Supplies of Mineral Resources
Never truly run out--just becomes too expensive to mine, transport, and process. (Economically depleted)• recycle/reuse• waste less• use less• find a substitute• do without
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Supplies of Mineral Resources
Depletion Time: how long it takes to use up a certain proportion (80%) of the mineral reserve at a given rate of use
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What to do as supplies decrease?1. mine lower-grade ores
> New tech> expensive> process more ore for same amount of mineral> *Water use> environmental impacts: increased land
disruption, waste, pollution> Biomining?
http://www.youtube.com/watch?v=6Arz1G_1QfE
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What to do as supplies decrease?
2. Get minerals from ocean> seawater, sediment, continental shelf,
hydrothermal ore deposits, manganese-rich nodules
> low concentration> Expensive (even minerals in large
concentrations)> Disputes over ownership> manganese nodules cover 25-50% of Pacific
Ocean floor– environmental effects of mining?
http://noc.ac.uk/science-technology/marine-resources/minerals-products/metals-sulphides-nodules
cobalt-rich ferromanganese crust
February 03, 2014
Economics of Nonrenewable Minerals• As resource becomes more scarce, prices should
rise> stimulates search for new deposits,
technology• *Government controls supplies and prices
> subsidies keep mineral prices low> help promote economic growth and national
security> What are the effects?
– Companies not motivated to find new technology to be more efficient
– Promotes waste
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Solution? Using mineral resources more sustainably• Materials revolution--find substitues
> silicon, ceramics, plastics> but not a complete substitute> has its own drawbacks (*plastic)
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Solution? Using mineral resources more sustainably• Recycling metals
> lower environmental impact than mining and processing ores
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Solution? Using mineral resources more sustainably• Decrease use and waste
> Ecoindustrial revolution: biomimicry > recycle and reuse> resource exchange webs
– wastes of one manufacturer becomes materials for another
– reduce resource need, pollution– stimualtes technolgoy
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Nanomaterials: what's the deal• Potentially eliminate need for mineral resources
> carbon, oxygen, silicon
• Nanosolar cells• Economy?• Environmental impacts (very small things)
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Test Wednesday on Chapter 14 and Chapter 15.
Chapter 14: Water Resources
Chapter 15: Mineral resources
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Review essay questions:
1. What are the three main strategies to increasing the freshwater supply for people? Choose one and describe the advantages/disadvantages.
2. How have humans contributed to the damage caused by floods?
3. What are mineral resources? What processes make minerals available?
4. Describe three specific negative impacts of mining practices.