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Mining of natural resources from the earth…. ….how did these resources get here?. See Chapter 16, Living in the Environment, G.T. Miller. Gold Mine http://www.rainforestweb.org/Rainforest_Destruction/Mining/. Minerals, rocks and fossil fuels are mined out of the earth
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Mining of natural resources from the earth….. ….how did these resources get here? See Chapter 16, Living in the Environment, G.T. Miller Gold Mine http://www.rainforestweb.org/Rainforest_Destruction/Mining/
Minerals, rocks and fossil fuels are mined out of the earth • The earth’s crust is composed of rocks and minerals(see p. 332-338 for some basic geology) • Element composition: http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/elabund.html • mineral = solid element or non C containing compound, with regular, internal crystalline structure & specific chemical composition…Ag, Au, C, S, NaCl, quartz…. • mica is a mineral…. http://www.pitt.edu/~cejones/GeoImages/1Minerals/1IgneousMineralz/Micas.html
Rocks are solid combinations of 1 or more minerals • Limestone = CaCO3 (sedimentary) • Quartzite = SiO2 (metamorphic) • http://images.google.com/images?hl=en&q=quartzite&um=1&ie=UTF-8&sa=N&tab=wi • Granite =SiO2, TiO2, Al2O3, Fe2O3, etc. (igneous) http://images.google.com/images?hl=en&um=1&sa=1&q=granite&btnG=Search+Images&aq=f&oq=
What else do we mine out of the ground? • Salt, clay, phosphates, sand, soil, bauxite • Coal, oil, natural gas, U • Renewable or nonrenewable? • What else?
How do we know where to mine? • Exploratory Wells • Aerial photos • Satellite images • Radiation monitoring • Magnetometer • Seismic surveys (use explosives, detect shock waves) • Chemical analysis of rock and water
Depending on where the resource is… • http://www.uky.edu/KGS/coal/coal_mining.htm
Surface mining Indiana Illinois • Most mining in U.S. • “Overburden” is stripped away • Wastes are “spoils” or “tailings”. http://www.in.gov/dnr/reclamation/protect_resources/bats/surface_mining.html http://www.isgs.uiuc.edu/servs/pubs/geobits-pub/geobit12/gb12b.htm
Strip Mining “Since the mid-1970s, strip-miners in Montana, as well as in other states, are required by law to remove overburden in an orderly manner, to refill the pits after mining the coal, restoring the overburden as nearly as possible to its original condition, and to replant it with the original types of vegetation. "The art and science of mine reclamation are now so highly developed," say geologists David Alt and Donald Hyndman, "that the recently worked sites are visible only to a knowing and practiced eye."1Some of the lignite mined here at Colstrip is used to generate electricity at the plant in the upper center. The rest is shipped to coal-fired generators in other parts of the country, via 100-car "unit" trains.” http://www.lewis-clark.org/content/content-article.asp?ArticleID=1567
Mountain top removal • At least two sides to every issue….. http://www.huffingtonpost.com/2009/02/13/court-rules-in-favor-of-m_n_166856.html • http://pittsburgh.indymedia.org/archives/archive_by_id.php?id=288&category_id=4
Subsurface mining What’s good about subsurface mining? What’s bad about it? • Kentucky coal mine: longwall mining More pixs: http://66.113.204.26/mining/coal/room_pill.htm http://www.coaleducation.org/Ky_Coal_Facts/types_of_mining.htm http://rogerphilpot.homestead.com/CoalEducation.html
Advantages Only way to access some resources Disturbs less than 1/10th as much land as surface mining Usually produces less waste material Disadvantages Dangerous Collapse of roofs & walls Explosions of dust & natural gas Lung diseases from mining dust Leaves much of the resource in the ground Subsidence (sinking of earth that is not slope related) Subsurface Mining
Cyanide heap leaching • At Wind Mountain Read about Zortman-Landusky mine http://www.nbmg.unr.edu/slides/mmo/24.htm More on ZL http://serc.carleton.edu/research_education/nativelands/ftbelknap/environmental.html
Why do these problems persist? • Public Land in US is cheap! U.S. General Mining Law of 1872… seetext;case study • Resource developers want to use U.S. land • Government subsidies • ?
What can we do? • Reduce consumption • Reuse stuff • Recycle • Enforce environmental protection • Look for substitutes • Biomining (use bacteria to “grab” the metal) • Mining seawater (high cost, who owns resource?) • Nanotechnologies (research to build at atomic & molecular level)