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Chapter 14 Notes: Geology and Nonrenewable Minerals
Environmental Effects of God Mining: Core Case Study
1) Typically removes enough rock to equal the weight of 50 automobiles to extract an amount of gold that
would fit inside your clenched fist.
2) Cyanide heap leaching is used to level entire mountains
a) Miners spray of solution of highly toxic cyanide salts onto huge open-air piles of crushed rock
b) The solution drains into storage ponds below the rocks
c) After circulated a number of times, the gold is removed from the ponds
3) Cyanide is extremely toxic to birds and mammals
4) Cyanide can leak into underground drinking water supplies and poison fish and other forms of life in lakes
and streams.
The earth is made up of a core, mantle, and crust and is constantly changing as a result of processes
taking place on and below its surface.
The earth’s interior consists of:
Core: innermost zone with solid inner core and molten outer core that is extremely hot.
Mantle: solid rock with a rigid outer part (asthenosphere) that is melted pliable rock.
Crust: Outermost zone which underlies the continents.
Tectonic plates: huge rigid plates that are moved with convection cells or currents by floating on
magma or molten rock.
The Earth’s Major Tectonic Plates
The extremely slow movements of these plates cause them to grind into one another at convergent plate
boundaries, move apart at divergent plate boundaries and slide past at transform plate boundaries.
Wearing Down and Building Up the Earth’s
Surface is done by Biological weathering,
chemical weathering and physical weathering.
The Earth’s crust consists mostly of rocks and minerals.
Three types of Rocks:
1. Sedimentary – made of sediments (ex: sandstone, shale)
2. Igneous – forms below or on the earth’s surface when magma cools and hardens (ex: granite, lava rock)
3. Metamorphic rock – forms when a preexisting rock is subjected to high temperatures, high pressures,
chemically active fluids, or a combination of these agents. These forces transform a rock by reshaping
its internal crystalline structure and physical properties. (ex: anthracite, slate, marble)
Rock Cycle: an important form of natural capitol; the slowest of earth’s cyclic processes, it recycles the earth’s
three types of rocks over many years
Minerals: an element or inorganic compound that occurs naturally in the earth’s crust as a solid with regular
internal crystalline structure; can be a single element, such as gold or silver, or a combination of elements, such
as salt or quartzite.
Mineral resources: concentration of naturally occurring material from the earth’s crust that can be extracted
and processed into useful products and raw materials at an affordable cost.
1. Fossil fuels- coal, oil, natural gas
2. Metallic minerals- aluminum, iron, copper, gold, silver, platinum, cadmium, etc.
3. Nonmetallic minerals- sand, gravel, limestone
4. Because they take so long to form, these components of the earth’s natural capitol are classified as
nonrenewable mineral resources.
Uses for Metallic minerals:
 Aluminum- used for packaging & structural in cars, aircraft & buildings
 Steel- essential in buildings & vehicles.
 Copper- good conductor
 Manganese, cobalt Chromium- all used in steel alloys
 Platinum- electrical equipment, catalyst in industry
Scarce minerals:
 Manganese, chromium, cobalt & platinum
 Strategic metal resources- essential for country’s economy & military strength
Distribution of Resources
 US, Canada, Russia, South Africa & Australia- supply most of worlds minerals
 United States, Germany & Russia- consume 75% of world’s metals
Ore: rock that contains a large enough concentration of a particular mineral – often a metal- to make a
profitable for mining and processing.
 Two components: Ore mineral (containing the desired mineral) and Gangue (waste materials)
 High-grade: contains a fairly large amount of the desired non-renewable mineral resource
 Low- grade: contains a small amount of the desired non-renewable mineral resource.
Removing Mineral Deposits: Mining
1) Surface Mining
a) Gigantic Mechanized equipment removes surface of earth and discards as waste
b) Used to remove 90% of non-fuel minerals & 60% of coal
c) Vocabulary
i) Overburden: the soil and rock overlying the useful mineral deposit
ii) Spoils: discarded waste materials
iii) Tailings:, unused materials usually left behind on the land when minerals are dredged from streams
d) Type used depends on resource being sought and local topography
i) Open Pit Mining-Large pit dug straight down
ii) Strip Mining-Dig large horizontal strips are very susceptible to chemical weathering and erosion by
wind or water.
iii) Contour Strip Mining- Used on hills/mountains- strip mining on terraces
iv) Mountain top removal – uses explosives and large power shovels
e) Last two types are extremely harmful to environment- cause a lot of erosion & tailings fill in streams
below. Also creates a lot of air pollution & water pollution.
2) Subsurface Mininga) Removes materials too deep for surface mining
b) Disturbs les than 1/10 the land as surface mining & produces less waste
c) Leaves much of the resources in the ground & is very dangerous
3) Two Laws
a) Clean Water Act- forbids stream destruction
b) Surface Mining Control & Reclamation Act of 1977
i) Requires mining companies to restore most surface mined land by grading and replanting
ii) Tends to be only partially successful & takes decades.
4) Mining Impacts:
a) Scarring and disruption of land surface
b) Subsidence
c) Pollutes the air and water
d) Toxin laced mining wastes can be blown elsewhere by wind or water erosion
e) Acid min drainage
f) Contaminates in water supplies can destroy some forms of aquatic life
g) Emit toxic chemicals into atmosphere.
Processing: Removing metals from ores
Smelting: heating ores to release metals
 Can emit enormous amounts of air pollutants
 Damage vegetation & acidify soils
 Cause water pollution
 Produces liquid and solid hazardous waste.
Minerals will never run out because we will stop mining them when they become too $$$$
When minerals become economically depleted there are 5 options1. Recycle or reuse existing supplies
2. Waste less
3. Use less
4. Find a substitute (nanotechnology)
5. Do without.
Mineral economics
 Mineral prices are controlled to such an extent
 Plentiful mineral resource is cheap when its supply exceeds demand
 When a resource becomes scarce- its prices rise. This can encourage exploration for new deposits,
stimulate development of better mining technology and make it more profitable to mine lower grade
ores.
 Many mineral prices are kept artificially low because many governments subsidize development of
mineral resources to help promote economic growth & national security.
Advantages of Taxing:
Provide governments with revenue
Create incentive for more efficient resource use,
Promotes waste reduction and pollution prevention
Encourage recycling and reuse of mineral resources.
Factors that limit low grade ore mining:
1. Increased cost of mining & processing larger volumes of ore
2. Availability of freshwater needed to mine and process
3. Environmental impacts
Possible Alternatives:
1) Biomining- removes desired metals from ores using bacteria/microorganisms. Can mine without moving
any earth. Problems is that it is slow and can take decades- only economically feasible with low grade ores
2) Ocean Mineral Resources:
a) Seawater- most ore too low grade to be economically feasible
b) Sediment deposits on continental shelf (manganese nodules)
c) Hydrothermal vent mineral deposits
d) Currently too deep & too expensive
e) Also mostly in international water-so who owns them is an issue
3) Substitutes for Mineral Resources
a) Nanotechnology
i) Nanotech- science engineering to create materials out of atoms and molecules.
ii) Could be used to remove industrial pollutants in air, soil & water or turn garbage into food.
iii) Advantages: Little environmental harm and prevents resource depletion
iv) Nanotechnology Could replace a lot of mineral resources that are becoming exhausted or expensive.
v) Disadvantages: There could be potential harmful impacts to environment/life- toxic to humans.
They can move across cell membranes & placentas.
b) Ceramics
i) Harder, stronger, lighter and longer lasting than many metals
ii) Can withstand high temps and resist corrosion
c) Plastics:
i) Has replaced metals for pipes
ii) Cost less than metals
iii) However- plastics are petrochemicals (made from Petroleum – crude oil – a fossil fuel which also
comes from the ground and is in limited supply)
Ecoindustry-
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Mimic how nature deals with waste
Waste outputs of one organism become the nutrient inputs of another
Industry can is in some places is doing this by recycling and reusing minerals and chemicals used in
industries instead of dumping them into environment.