Earth Resources

• Statement:
• The Earth is a closed system with finite resources



• Resources vs. Reserves
• Resource: a concentration of naturally occurring solid, liquid, or gaseous material in or on the Earth's crust in such form and amount that economic extraction of a commodity from the concentration is currently or potentially feasible
• Reserve: part of the resource that can be extracted economically
• Measured: amount is known from a working mine



• Economics: concentration, transportation, labor costs, market price, technology



• Environmental Impacts
• Surface vegetation and habitats are destroyed
• Increased erosion



• Spoil heaps
• Groundwater contamination



• Gangue



• Smelting
• Air pollution






• Types of Earth Resources
• Construction materials
• Sand, gravel, limestone, building stone, crushed stone



• Nonmetallic resources
• Gypsum, diamond, corundum, gemstones



• Metallic resources
• Gold, silver, platinum, copper, lead, zinc, ....



• Energy resources





• renewable vs. non-renewable
• Solar, tidal, geothermal, coal, oil ??
• 90% of the fuel we use is nonrenewable
• Analyst opinion vs. public opinion
• Hubbert Production Cycle



• Mineral Resources
• Distribution vs. consumption




Mineral	% Imported	Major Supplier
Columbium	100	Brazil, Canada, Thailand
Mica	100	India, Belgium, France
Strontium	100	Mexico, Spain
Manganese	100	South Africa, France
Bauxite	100	Jamaica, Guinea, Australia
Platinum	88	South Africa, Russia, UK
Cobalt	82	Zaire, Zambia, Canada
Chromium	80	South Africa, Zimbabwe, Turkey
Nickel	74	Canada, Australia, Norway
Tin	73	Malaysia, Thailand, Brasil
Potassium	67	Canada, Israel, Russia
Zinc	30	Canada, Mexico, Peru






• Types Renewable Energy Sources
• Solar energy
• Use
• mirrors and lenses focus the Sun's energy to heat water and turn a turbine



• photovoltaic cells



• Pros
• clean



• Cons
• distributed over a broad area



• not economical (yet)



• inefficient (only extracts 10-15% of energy that falls on them)



• Biomass
• Use
• combustion of living tissue



• Pros
• reduces landfill waste



• Cons
• CO₂



• Hydroelectric Power
• Use
• water flowing downhill is used to turn turbines



• Pros
• inexpensive and clean
• dams are flood-control devices
• irrigation and recreation



• Cons
• destruction of habitat
• sediment chokes the dam





• Wind
• Use
• wind turns a turbine



• Pros
• pollution free
• economically free too



• Cons
• very expensive
• unreliable
• noise pollution
• unseemly appearance
• large tracts of land needed



• Geothermal
• Use
• geothermal gradient (3 C/ 100 m)
• concentrated amounts
• pump hot water (150 C) to the surface where it flashes to steam and can turn a turbine
• space heating



• Pros
• pollution free
• long-lived



• Cons
• high dissolved solids in water
• subsidence



• Tidal
• Use
• dams are built at the entrance to a tidal bay
• as tides go up and down and water enters and leaves the bay, it turns turbines



• Pros
• no pollution



• Cons
• need a big tidal range (8 m)
• very localized
• could only supply 1% of the worlds supply



• Nuclear
• Use
• fission of uranium-235 in a nuclear reactor
• bombarding the uranium with neutrons in a "fuel rod"
• as a result of splitting the uranium nucleus into lighter isotopes, a small mass converted to energy
• heat drives a turbine



• Pros
• very efficient
• when controlled, very little pollution



• Cons
• mining and production hazards
• waste disposal problems
• thermal pollution