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TRANSCRIPT
General Mining Law, 1872
Concrete – sand,
gravel, crushed
limestoneSalt
Copper
Minerals – Elements or compounds that occur naturally in
Earth’s crust
Rocks – mixtures of minerals
Ore – rock that contains enough of a mineral for it be be profitable to mine High-grade – contain large amounts of minerals
Low-grade – contain smaller amounts of minerals
Metals – minerals that are malleable, lustrous, & good conductors
Mineral Distribution and Formation
• Abundant (e.g., Al, Fe)
• Scarce (e.g., Cu, Mo)
• Must be accessible & profitable to mine
• Unequal global distribution
Concentration of Minerals are the result of:
Magmatic concentration Layering of magma by density is assoc. w/certain minerals
Hydrothermal processes Heated water dissolves minerals in rocks & carried in
solution
Sedimentation Weathered particles are transported & deposited in as
sediments
Evaporation Minerals are left behind; may be covered with sediments
Discovering Mineral Deposits
– aerial photos / satellite images geologic formations
– examine magnetic field
– Seismographs
– Drill for samples & analyze composition– http://www.grist.org/article/2010-01-19-stephen-colbert-on-mountaintop-removal-mining-video
– http://understory.ran.org/2010/01/19/mountaintop-removal-on-colbert-nation/
– http://www.ilovemountains.org/
– http://www.hippocampus.org/hippocampus.php/course_locator.php?course=Environmental%20Science&lesson=47&topic=1&width=800&height=550&topicTitle=Area%20Strip%20Mining&skinPath=http://www.hippocampus.org/hippocampus.skins/default
• Extracting Minerals• Subsurface Mining
• Shaft mine
• Direct vertical shaft to vein; ore is broken up & removed in buckets
• Slope mine
• Slanting passage for ore to be removed in cars
• Surface mining• Open-pit mining quarries are dug
• Strip mining
• trench is dug to extract minerals
• parallel new trench for overburden (spoil bank – loose rock)
• Overburden – soil & rock overlying useful deposits
• Processing Minerals• Smelting – ore is melted at high temperatures to
separate impurities from molten metal
• Blast furnace• Slag –molten mixture of impurities that is disposed
of
• Requires air pollution control devices
• http://www.hippocampus.org/hippocampus.php/course_locator.php?skinPath=http://www.hippocampus.org/hippocampus.skins/default&course=Environmental%20Science&lesson=48&topic=1&topicTitle=Ore%20Processing
Began in 1947; 2.5 million jobs globally as of 2012.
Rock is broken by injecting a pressurized mix of water, sand and chemicals Solutuion is injected into wellbore
Cracks are formed in rock formations.
Natural gas, petroleum and brine flow more freely
Costs Ground water contamination
Deption of fresh water.
Air pollution
Earthquakes
Noise pollution
Associated human and environmental health risks
Benefits More access to fossil fuels.
Domestic fuel source.
Economical (?)
Disturbs large areas of land Destroys vegetation, increases erosion, increases water & air
pollution
Uses huge quantities of water Pump out water to keep mine dry
Affects water quality Contain high levels of heavy metals (As & Pb)
Dissolved toxins, ACID MINE DRAINAGE, toxic pulses
Cost-benefit Analysis of Mine Development Benefits of mining ($) vs. benefits of preservation
Costs of damage
Benefits decline as resources decline
Environmental Impacts of Refining Minerals
Problems from Refining: Tailings – impurities left over after processing
Left in piles on ground or ponds
Contain toxins contaminate soil, water, air
Smelting plants Release many air pollutants (ex. S, Pb, As, Zn, Cd)
Pollution-control devices
Release dangerous liquid & solid wastes
Energy Intensive
The problem of tailings
Case-in-Point: Copper Basin, TN
Surface Mining Control and Reclamation Act
Reclamation Goals Prevent further degradation & erosion
Eliminating sources of toxic pollutants
Making land productive for non-mining purposes
Derelict lands Lands degraded from mining
Reclamation Process Filling in & grading derelict land
Planting vegetation Need plants that tolerate toxins & little/no topsoil.
Funding limitations
Surface Mining Control and Reclamation Act Requires reclamation of areas that were surface mined
for COAL
Creative Approaches to Cleaning Up Mining Areas Conversion to wetlands
Series of wetlands to trap sediments & remove toxins
Bacteria consume S, Zn & Cu percipitate
Manure increase pH
Phytoremediation Use of plants to absorb and store toxins (ex. Ni)
Plants are disposed of or burned http://www.hippocampus.org/hippocampus.php/course_locator.php?course=Environmental%20Science&lesson=47&
topic=2&width=800&height=550&topicTitle=Mining%20for%20Borax&skinPath=http://www.hippocampus.org/hippocampus.skins/default
• Developed• Use minerals to make products
• Rely on developing countries for resources
• Significant environmental damage due to mining
• Developing• Need more minerals as become industrialized
• Little env reg & clean up efforts great environmental damage
• Industrialization increases demand for minerals
U.S. and World Use North American consumption of selected metals
Distribution Versus Consumption Some minerals needed for many industrial processes,
but only found in abundance in few places Ex. chromium
Results in dependence Stockpiling common
Strategic minerals – critically important metals
Reserves / annual production
Mineral reserves Identified mineral deposits that are presently profitable
to mine
Mineral resources Undiscovered mineral deposits or low-grade deposits
that are unprofitable to mine
Total resources (world reserve base) Reserves + Resources
Changes with economy, politics, & technology
Many deposits have NOT been exploited because:• accessibility problems (ex. Indonesia & malaria)
• technology issues (ex. Poles)
• too deep
• Potential for unknown deposits in developing countries (ex. Andes, Amazon Basin)
Minerals in Antarctica Negotiations for which countries have access to
resources
Antarctic Treaty (1961) limits activities to peaceful uses
Madrid Protocol (Environmental Protection Protocol to the Antarctic Treaty), 1990 Prohibits exploration & development for 50 years
Valuable in regulating global environment
Mineral reserves in ocean may increase supplies Minerals from seawater
Mine sea floor
Affect seabed organisms & land where ore is processed
Manganese nodules on ocean floor with several minerals
Minerals from the Ocean
U.N. Convention on the Law of the Sea International treaty for international waters
Constitution of the ocean
Protects ocean’s mineral resources from being mined off seabed
Advanced Mining and Processing Technologies Ability to exploit low-grade ores
Better technology
Increased energy efficiency
Environmental costs may be too high
Biomining Microorganisms are used to extract minerals from low-grade
ores (ex. Bacterium + sulfuric acid Cu
Finding Mineral Substitutes Substituting inexpensive / abundant resources for
expensive / scarce resources
E.g., Glass, plastics, and aluminum have substituted for tin
Mineral Conservation Reuse same product used over and over
Recycling - product is processed into another product
Changing Our Mineral Requirements
fight the “throw away” mentality