Unit 4: Earth’s Resources

1. Unit 4: Earth’s Resources Environmental Science

2. NONRENEWABLE RESOURCES A nonrenewable resource is a natural resource that cannot be re-made or re-grown at a scale comparable to its consumption.

3. COAL, PETROLEUM, AND GAS Coal, petroleum, and natural gas are considered nonrenewable because they can not be replenished in a short period of time. These are called fossil fuels.

4. HOW IS COAL MADE ???

5. HOW ARE OIL AND GAS MADE ???

6. WHAT WAS THE DIFFERENCE BETWEEN COAL AND OIL/GAS?

7. NUCLEAR ENERGY Nuclear fission uses uranium to create energy. Nuclear energy is a nonrenewable resource because once the uranium is used, it is gone!

8. RENEWABLE RESOURCES Renewable resources are natural resources that can be replenished in a short period of time. ● Solar ● Geothermal ● Wind ● Biomass ● Water

9. SOLAR Energy from the sun. Why is energy from the sun renewable?

10. GEOTHERMAL Energy from Earth’s heat. Why is energy from the heat of the Earth renewable?

11. WIND Energy from the wind. Why is energy from the wind renewable?

12. BIOMASS Energy from burning organic or living matter. Why is energy from biomass renewable?

13. WATER or HYDROELECTRIC Energy from the flow of water. Why is energy of flowing water renewable?

14. Metal Resources Biggest Users of Metals • United States • Japan • Europe Biggest Producers • South America • South Africa • Former Soviet Union .

15. Metal Resources

16. Non-Metal Resources • Sand & gravel • Uses: brick & concrete construction, paving, road filler, sandblasting, glass (high silica content sand) • Limestone • Uses: concrete, road rock, building stone, pulverized to neutralize acidic soil or water. • Evaporites- halite, gypsum, potash • Uses: halite- rock salt for roads, refined into table salt • Gypsum- makes plaster wallboard • Potash- for fertilizer (potassium chloride, potassium sulfates) • Sulfur deposits • Uses: sulfuric acid in batteries & some medicinal products

17. Steps in Obtaining Mineral Commodities • Prospecting- finding places where ores occur • Mine exploration & development- learn whether ore can be extracted economically • Mining- extract ore from ground • Beneficiation- separate ore minerals from other mined rock • Smelting & refining- extract pure mineral from ore mineral (get the good stuff out of waste rock) • Transportation- carry mineral to market • Marketing & sales- find buyers & sell the mineral

18. Types of Mining • Surface- scoop ore off surface of the earth or dig big holes and scoop • Cheap • Safe for miners • Large amount of environmental destruction • Subsurface- use shafts to reach deeply buried ores • Expensive • Hazardous for miners • Less environmental damage

19. Types of Surface Mining 1. Open Pit Mining • Overlaying material is removed using large equipment • Creates pits that are hundreds of meters wide and hundreds of meters deep.

20. Types of Surface Mining 2. Strip mining • Like open pit but not as deep of a pit • Same environmental damage

21. Large bucket wheel extractor being moved through Germany. Moves 10 meters per minute. Takes 5 people to operate. Used in strip mining

22. Types of Surface Mining • Dredging • Sand is removed from bottom of ocean • Can be done to restore beaches (after hurricane) • Destroys fragile benthic ecosystems

23. Types of Subsurface mining • Underground Coal mining • Shaft mine • Slope mine • Drift mine

24. Types of Subsurface mining • Room and Pillar mining • Remove rock/ore from rooms and leave pillars for support.

25. Types of Subsurface mining • Longwall mining • One long strip (wall) of coal is mined in a single strip (0.5 – 1.0 m at a time)

26. Health Problems • mine collapse • fire (methane, coal dust, etc.). • asphyxiation (methane, carbon monoxide) • pneumoconiosis (from inhaling coal dust) • asbestosis (from inhaling asbestos fibers) • silicosis (from inhaling silicate dust) • heavy metal poisoning (e.g. mercury) • radiation exposure (in uranium mining)

27. Environmental Damage • Gaping holes in ground (old open pit mines) • Accidental draining of rivers and lakes • Disruption of ground water flow patterns • Piles of gangue- mine tailings (mining waste) • Loss of topsoil in strip-mined regions (350 to 2,700 km2 in US alone) • Spoil banks are where holes were filled in with waste- cheap & easy- susceptible to erosion, chemical weathering, causes high sediment runoff in watersheds. Steep slopes are slow to re-vegetate (succession happens slowly- no topsoil) • Contamination of soil or water from heavy metals (e.g. arsenic, mercury) in mine tailings. • Contamination from sulfuric acid (H2SO4) produced through weathering of iron sulfide (FeS2, pyrite) in tailings. • 4FeS2 + 14H2O = 4Fe(OH)3 + 8H2SO4 • Water leaking into mine shafts, washes dissolved metals & toxic material into water sources. • (550,000 abandoned mines in U.S.- 12,000 mi of rivers & streams contaminated with mine drainage- cost to clean up $32-$72 billion)

28. Acid Mine Drainage

29. Acid Mine Drainage The impact of mine drainage on a lake after receiving effluent from an abandoned tailings impoundment for over 50 years

30. The same tailings impoundment after 7 years of sulfide oxidation. The white spots in Figures A and B are gulls. Relatively fresh tailings in an impoundment. http://www.earth.uwaterloo.ca/services/whaton/s06_amd.html

31. Mine effluent discharging from the bottom of a waste rock pile (gangue)

32. Shoreline of a pond receiving AMD showing massive accumulation of iron hydroxides on the pond bottom

34. Surface Mining Control & Reclamation Act (SMCRA) • 1977 • Requires better restoration of strip-mined lands • Restoration is difficult & expensive • Takes long time for soil to regain fertility • Topsoil gets buried • Compacted, poor drainage • Root growth restricted • Minimum cost- $1000 per acre • Complete restoration (if possible)- $5,000 per acre

37. History of Supplemental Energyin United States • Wood through mid-1800s • Renewable • Maximum sustained yield limits supply • Coal replaced wood by 1900 • Oil, natural gas exploited (since mid-1900s) #1-oil, #2-natural gas, #3-coal - all non-renewable • Use growing dramatically

38. 100 Wood Coal 80 Natural gas 60 Contribution to total energy consumption (percent) Oil 40 Hydrogen Solar 20 Nuclear 0 1800 1875 1950 2025 2100 Year

39. How long will supplies last? • U.S. (5% pop) uses 25% of energy • Depends on: - rate of use - discovery of new supplies • Resource supply lifetime - oil - 30-60 years - natural gas - 50-200 years - coal - 650-900 years

40. North American Energy Resources

41. Oil Shale and Tar Sands • Oil shale 3X conventional • Kerogen 25 gallons/ton Energy in=energy out • Tar sands • Bitumen 3X return on energy inputs

42. Natural Gas • 50-90% methane • Propane, butane removed, liquified • Cleanest burning, lowest costs • Problems: leaks, explosions

43. Coal Carbon (energy content) and sulfur

44. Coal • Bituminous most abundant (52%), but high in sulfur • Anthracite most ideal (high energy, low sulfur), but least abundant (2%) • Lignite (8%) low energy, low pollution potential

45. Coal • Surface versus subsurface mines

46. North American Energy Resources

47. Burning Coal More Cleanly • Fluidized-Bed Combustion -calcium sulfate (limestone) used w/ Coal.

48. Coal Gasification - methane Remove dust, tar, water, sulfur Raw coal Recover sulfur Air or oxygen Raw gases Steam Clean methane gas O2 2CO 2C Coal + Pulverizer Recycle unreacted carbon (char) CO + 3H2 CH4 + H2O Methane (natural gas) Slag removal Pulverized coal

49. Coal Liquefaction - liquid fuels • Both gasification and liquefaction lose 30-40% of energy contained in coal

50. Nuclear Energy • Tremendous potential, plagued by safety and cost problems • 3 ways to produce nuclear power 1) conventional nuclear fission reactor 2) breeder nuclear fission reactor 3) nuclear fusion reactor