Geologic Resources: Nonrenewable Mineral and Energy Resources

1. Geologic Resources: Nonrenewable Mineral and Energy Resources G. Tyler Miller’s Living in the Environment 13th Edition Chapter 15 Dr. Richard Clements Chattanooga State Technical Community College Modified by Charlotte Kirkpatrick

2. Key Concepts • Types of mineral resources • Formation and location of mineral resources • Extraction and processing of mineral resources • Increasing supplies of mineral resources • Major types, acquisition, advantages, and disadvantages of fuel resources

3. Why mine minerals?

4. Nature of Mineral Resources • Mineral resources: concentration of naturally occurring material in or on the earth’s crust that can be extracted and processed into useful materials at an affordable cost • Metallic: iron, copper , aluminum • Non-metallic: salt, clay, sand, phosphates, soil • Energy resources: Coal, oil, natural gas, uranium

5. General classification of mineral resources Fig. 15-2 p. 339

6. Nature and Formation of Mineral Resources • Magma: magma flows to the surface at divergent and convergent plate boundaries it cools, and crystallizes into mineral containing igneous rocks. • Hydrothermal: hydrothermal vents allow seeping of metal-bearing solutions to cool and their dissolved minerals to form hydrothermalore deposits. • Manganese nodules: cover 25-50% of the ocean floor very concentrated form of manganese and other important metals.

7. Hydrothermal vent communities and deposits

8. Ores From Sedimentary and Weathering Processes Sedimentary processes: Placer Deposits: form as deposit settle out as flowing water slow down:gold Evaporites: water evaporates from inland seas or lakes with no outlets and concentrations of dissolved salts increase and precipitate out for form evaporites mineral deposits such as Salt, borax, and sodium carbonate Weathering: moving water removes soluble ions and leaves behind ions that form Residual deposits of metal ores:Iron and Bauxite ore

9. Salt mine from Sal Island

10. Finding Nonrenewable Mineral Resources • Satellite imagery • Aerial sensors (magnetometers) • Gravity differences • Core sampling • Seismic surveys • Chemical analysis of water and plants

11. Removing Nonrenewable Mineral Resources Surface mining: basics • Overburden: soil and rock removed by stripping away by mechanized equipment • Spoil: Waste material discarded from overburden

12. Removing Nonrenewable Mineral Resources: Surface Mining Types • Open-pit: land is dug up into a large hole to remove deposits of mineral ores and sandstone, gravel and stone. • Dredging: removal of minerals from the ocean floor

13. Removing Nonrenewable Mineral Resources: Surface Mining Types (cont.) • Area Strip Mining: flat terrain mining, removal of overburden and in strips and if not restored spoil banks left behind • Contour Strip Mining:same as above except on hilly terrain and leftover is a erodable wall of dirt called a high wall. • Mountain Top Removal: explosives and large machinery used to remove mountain tops to expose seams of coal underneath. Very environmentally damaging.

14. Types of Surface Mining

15. Removing Nonrenewable Mineral Resources Subsurface mining:removes minerals too deep for surface mining • Room and pillar • Longwall • Mine shafts and tunnels

16. Types of Subsurface Mining

17. Environmental Effects of Extracting Mineral Resources Fig. 15-6 p. 343

18. Environmental Effects of Processing Mineral Resources • Ore mineral: Extracted from ore, contains the desired metal • Gangue: Also extracted from ore, waste material • Tailings: Piles of gangue waste left behind, allows toxic metals to reach groundwater and surface water supplies • Smelting: Used to separate the metal from the other elements in the ore mineral. See Case Study p. 345

19. One effect of tailings left behind Above: A simplified diagram showing natural cyanide degradation processes at the tailings storage facilities.1. Waste Rock Embankment. 2. Decant pond. 3. Natural ground.

20. Typical Lifecycle of a metal resource

21. Acid Mine Drainage Fig. 15-7 p. 344

22. Environmental Effects of Using Mineral Resources • Disruption of land surface • Subsidence: sinking of the land • Erosion of solid mining waste: tailings, spoil banks • Acid mine drainage: pollution of water sources as rainwater seeps into ground and surface water • Air pollution: smelters, toxic emissions • Storage and leakage of liquid mining waste: smelters, holding ponds

23. Supplies of Mineral Resources • Economic depletion • Depletion time: shortened by recycle, reuse, reduce, improved technology, new discoveries, higher prices • Reserve-to-productionratio: the number of years that proven reserves of a particular nonrenewable mineral will last at current annual production rates. Fig. 15-9 p. 346

24. Supplies of Mineral Resources • Foreign sources: we are highly dependent on sources outside the U.S. • Economics:mine higher grade ore first, lower grade ores are more environmentally damaging. Most of the environmental costs for mining are not included in the prices for processed metals and products • Follow normal supply and demand • Mining law of 1872: hard rock minerals may be mined without paying royalties, by patenting parcels of land, no environmental cleanup required,

25. World Mineral Map

26. World Mineral Reserves

27. Environmental concerns Environmental concerns: 5-10% of world energy use is for extraction of minerals. Major contributor to air and water pollution. Largely determined by mineral content or grade. Mining on Public lands; national forests, parks, resource lands and wilderness.

28. Supplies of Mineral Resources • Mining lower grade ores: New earth-moving equipment, improved techniques for removing impurities, technical advances in mineral extraction and processing • Mining the ocean: Many mineral elements found in seawater, sediments and deposits on the shallow continental shelf, hydrothermal ore deposits, and manganese rich nodules • Finding substitutes: Mainly plastics and ceramics

29. Evaluating Energy Resources • Renewable energy:Energy resources that can be used sustainably and be available for future generations. • Non-renewable energy: Energy that has a finite supply and the only way to increase supply is through conservation techniques. • Environmental effects: Use of mostly nonrenewable energy resources has resulted in an increase in air and water pollution, land disruption, and greenhouse gas emissions.

30. Evaluating Energy Resources U.S. World Fig. 15-12 p. 351 Nonrenewable:91% Renewable : 9% Nonrenewable: 82% Renewable: 18%

31. Evaluating Energy Resources • Future availability: depends largely on how we use the resources. • Cost: affected by the promotion of subsidies, and tax breaks, availability of resource

32. Net Energy Yield • Net energy yield: Usable amount of high-quality energy available from a given quantity of an energy resource. • Determined by thetotal energy available from a resource minusthe energy needed to find, extract, process, and bring to consumers. • Figured by estimating the total energy available for use over its lifetime minus the amount of energy 1. used (1st law), 2.automatically wasted (2nd law), and 3. Unnecessarily wasted for finding, processing, concentrating, and transporting.

33. Net Energy Ratios Photovoltaic (solar) cells

34. Fuel Resources Over Time

35. Some Important Energy Sources Fig. 15-10 p. 350

36. Oil • Petroleum (crude oil): oil as it comes out of the ground, is a thick liquid consisting of hundreds of combustible hydrocarbons along with small amounts of sulfur, oxygen, and nitrogen impurities. Formed from decomposition of dead organic matter from plants (plankton) and animals buried under lake and ocean sediments from 2-140 million years ago (MYA)

37. Oil • Primary recovery:Involves drilling a well and pumping out the oil that flows by gravity into the bottom of the well. • Secondary recovery: After flowing oil is removed water can be infected into a nearby well to force some of the heavy oil to the surface. • Tertiary recovery: steam or carbon dioxide gas are injected to remove approximately 10% of the remaining heavy oil

38. Oil • Oil and Natural gas are usually found together trapped in a dome deep within the earth’s crust. • Heavy Crude oilis too expensive to extract so most wells are only getting about 35% of the oil out. • Drillingcauses little land damage yet it always involves some oil spills on land and at sea and the harmful effects of using associated with extraction, processing, and using oil

39. Oil • Refining: based on boiling points components are removed at various levels in a giant distillation column. The most volatile components with the lowest boiling points are removed at the top. • Transporting: by pipeline, trucks or ships • Petrochemicals: Products of oil distillation that are used as raw materials in industrial organic chemicals, pesticides, plastics, etc.

40. Oil refining by Distillation Fig. 15-18 p. 355 Most volatile

41. Who has the World’s Oil? Oil reserves are identified deposits from which oil can be extracted profitably at current prices with current technology. OPEC contains 67% of the world’s crude oil reserves (see bottom of page 355). Mainly in Saudi Arabia (26%) The remaining is found in Latin America, Africa, the former Soviet Union, Asia, the United States and Western Europe.

42. North American Energy Resources Fig. 15-20 p. 356

43. Oil Use in the U.S. Most oil drilled in the U.S. comes from offshore drilling in the Gulf of Mexico and form drilling in Alaska’s North Slope. U.S. only produces 3% of the world’s oil yet uses 26% of the crude oil extracted each year. Therefore, much of our oil is imported each year, mainly from the Persian Gulf 1973 imported 36%, 2001 imported 55% and predicted to import 61% by 2010.

44. Oil Usage and How Long Will it Last? We are not currently running out of oil!! However, our known reserves of oil are limited and if we continue to use them at current rates we may have only 53 years left. And if we increase usage by only 2% per year only 42 years of oil are left. Undiscovered oil supplies might add another 20-40 years to the global supplies. See page 358

45. Oil Consumption Developed countries Developing countries

46. Pros and Cons of Oil

47. Oil Shale and Tar Sands • Oil shale: shale rock that contains oil. Keragen must be refined before use and to be sent by pipeline to the refinery it must be heated to increase flow and processed to remove impurities. • Keragen: actual substance locked in the shale, converted to oil • Tar sand: sand that contains clay, sand, water and bitumen Bitumen must be removed, purified, and chemically upgraded into a synthetic crude oil suitable for refining. Canada has a very rich Tar sand supply and has been using it since 1978 • Bitumen: heavy oil with a high sulfur content (high sulfur oil)

48. Pros and Cons of Shale Oil and Tar Sands

49. Natural Gas • 50-90% methane with small amounts of heavier gases (propane,butane) and hydrogen sulfide • Conventional gas:Lies just above crude oil reservoirs • Unconventional gas: found by itself in underground sources. Not economical to extract, yet. • Ex. Methane hydrate: composed of small bubbles of natural gas trapped inice crystals deep under the arctic permafrost and beneath deep ocean sediments.

50. Natural Gas • Liquefied petroleum gas (LPG): When a natural gas field is tapped the propane and butane are liquefied and removed and stored in pressurized tanks mainly for use in rural areas not serviced by gas pipelines. • Liquefied natural gas (LNG):The remainder of the gas is dried, cleansed of impurities, and pumped into pressurized pipelines (natural gas at your homes). Then, if exposed to a very low temperature, it can be converted into LNG. And if refrigerated it can be transported by tankers • Approximate 200 year supply