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Geology and Nonrenewable Minerals Chapter 14. Core Case Study: Environmental Effects of Gold Mining Page 345  Gold producers South Africa Australia United.

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Presentation on theme: "Geology and Nonrenewable Minerals Chapter 14. Core Case Study: Environmental Effects of Gold Mining Page 345  Gold producers South Africa Australia United."— Presentation transcript:

1 Geology and Nonrenewable Minerals Chapter 14

2 Core Case Study: Environmental Effects of Gold Mining Page 345  Gold producers South Africa Australia United States Canada  Cyanide heap leaching Extremely toxic to birds and mammals 2000: Collapse of a dam retaining a cyanide leach pond Impact on organisms and the environment

3 14-1 What Are the Earth’s Major Geological Processes and Hazards? 1) The earth is a dynamic planet a) Geology: study of dynamic process occurring on the earth’s surface & interior b) 3 major zones: core, mantle, crust c) Core: inner, extremely hot & has a solid inner part surrounded by a liquid core of molten material d) Mantle: thick, most solid rock e) Athenosphere: zone of hot, partly melted rock that flows like soft plastic f) Crust: outer, thinner layer

4 14-1 What Are the Earth’s Major Geological Processes and Hazards? 2) The earth moves a) Convection cells: move large volumes of rock & heat in loops within the mantle b) Tectonic plates: rigid plates that move atop the mantle c) Lithosphere: combination of the continental & oceanic crust & the outer part of the mantle d) Most geologic activity occurs at the boundaries of the plates

5 Fig. 14-2, p. 348

6 Fig. 14-3, p. 348

7 Fig. 14-4, p. 349

8 14-1 What Are the Earth’s Major Geological Processes and Hazards? e) Causes mountains, earthquakes & volcanoes f) oceanic ridges form when magma rises as plates move apart g) Subduction occurs when the continental plate slides over an oceanic plate (subduction zone) h) Trench: forms at the boundary of 2 converging plates i) Transform fault: plates slide & grind past one another

9 Fig. 14-5, p. 350

10 14-1 What Are the Earth’s Major Geological Processes and Hazards? 3) Building up and wearing down the surface a) Internal geologic processes: build up the earth’s surface in the form of crusts b) External geologic processes: wear down the surface & move material from one place to another c) Weathering: breaks down rock, helps form soil d) Erosion: Chapter 12 4) Volcanoes: Occur where magma reaches the surface through a fissure (lava)

11 Fig. 14-6, p. 351

12 14-1 What Are the Earth’s Major Geological Processes and Hazards? 5) Earthquakes: a) shifting or breaking forming a transform fault b) Seismic waves: energy produced by an earth quake c) Points 1. focus: where it begins below the surface 2. epicenter: found on the surface above the focus 3. Magnitude: severity of the earthquake 4. Amplitude: size of the wave 5. Seismograph: used to measure earthquakes

13 14-1 What Are the Earth’s Major Geological Processes and Hazards? d) Richter scale: measures intensity, with each number being 10X that of the lower number e) Aftershock: smaller earthquake f) Reducing loss of life and damage: 1. locate active fault lines 2. Establish codes that regulate placement and design of buildings

14 Fig. 14-7a, p. 351

15 14-1 What Are the Earth’s Major Geological Processes and Hazards? 4) Tsunamis (tidal waves): a) large waves generated when part of the ocean floor suddenly rises or drops b) Can be detected by ocean buoys and pressure recorders on the ocean floor c) Between killed people in the Pacific Ocean region. d) Coral reefs & mangrove forests reduce damage

16 Fig. 14-8, p. 352

17 Indonesia June 23, 2004 before tsunami

18 Dec. 28, 2004 after tsunami

19 14-1 What Are the Earth’s Major Geological Processes and Hazards? 5) Gravity and earthquakes can cause landslides a) Mass wasting: loose soil & rock slide down a slope b) Can occur quickly c) Human activities increase problem ex: clear cutting, road building, crop growing and building on slopes

20 14-2 How Are the Earth’s Rocks Recycled? 1) Types of rocks a) Mineral: element or compound occurring naturally in the crust as a solid b) Rock: solid combination of 1 or more minerals in the crust c) Classes: 1. Sedimentary: formed as sediments accumulate over time and the weight puts pressure on the lower layers (sandstone & shale-sand) (dolomite & limestone-shells/skeletons) (coal- plant remains)

21 14-2 How Are the Earth’s Rocks Recycled? 2. Igneous: forms below (granite) or on (lava rock) the surface when magma reaches the crust and cools, forms the bulk of the crust 3. Metamorphic: preexisting rock is subjected to high temperatures, high pressures, chemically active fluids or a combination (anthracite coal, slate, marble) 2) Rock Cycle: process of rocks changing from one form to another (know page 354)

22 Fig , p. 354

23 14-3 What Are Mineral Resources, and what are their Environmental Effects? 1) We use a variety of nonrenewable resources a)Mineral resource: concentration of naturally occurring material from the crust that can be extracted and processed into useful products at an affordable cost b) Ore: rock containing a large enough concentration to make it profitable to mine c) Sand & gravel are the most widely used nonmetallic mineral d) Reserve: estimated supply of a resource

24 14-3 What Are Mineral Resources, and what are their Environmental Effects? 2) Minerals use has advantages and disadvantages a) Life cycle b) Benefits: generates income, government revenue, employment c) Disadvantages: uses enormous energy, disturbs land, erodes soil, produces waste & pollutants

25 14-3 What Are Mineral Resources, and what are their Environmental Effects? 3) Surface Mining: a) Equipment removes overburden (soil & rock) b) This waste material is called spoils c) Tailings: unused material from dredging d) Open-pit: Dig holes and remove the ore e) Area strip mining: strip away overburden and power shovels remove the mineral deposit f) Contour strip mining: Power shovels cut a series of terraces into the side of a hill g) Mountain top removal:

26 Open pit

27 Fig , p. 357

28 Fig , p. 357 Contour strip

29 Fig , p. 358 Coal strip mine in Germany

30 Fig , p. 359 Mountain top removal

31 14-3 What Are Mineral Resources, and what are their Environmental Effects? 4) Harmful effects: a) Scarring & disruption of land surface b) Spoils & tailings are susceptible to weathering & erosion c) Mountain top: destroys forests & buries streams d) Toxic wastes e) Degrades biodiversity f) Pollutes streams and rivers g) Cleanup is expensive ($70 billion in US, trillions world wide)

32 14-3 What Are Mineral Resources, and what are their Environmental Effects? h) Subsurface disturbs less than 1/10 the amount of land, but leaves more mineral behind i) Subsurface is more expensive and dangerous j) Causes subsidence k) Solid waste (3/4 of all US solid waste) l) Causes air and water pollution m) Uses huge amounts of water 5) Removing metals from ores has harmful effects a) Gangue: waste from extracted ore

33 14-3 What Are Mineral Resources, and what are their Environmental Effects? b) Tailings produced may release toxic metals into water sources c) Smelting (heating ore to remove the metal) produces air pollutants d) Liquid & solid hazardous wastes are produced

34 14-4 How Long Will Supplies of Nonrenewable Mineral Resources Last? 1) Uneven distribution of minerals a) Massive exports can deplete supplies of a countries resources b) 5 nations ( US, Canada, Russia, S. Africa & Australia) supply most of the non-renewable mineral resources c) Since 1950, there has been a sharp rise in the total & per capita use in the US d) The US has depeted some of its resources & currently imports 50% or more of the 24 most important mineral resources

35 14-4 How Long Will Supplies of Nonrenewable Mineral Resources Last? e) Concern for 4 strategic metals (MN, Co, Cr, & Pt) 2) Economic depletion a) Future supply depends on actual supply & rate of use b) Economically depleted means it costs more to find, remove and process than it is worth c) 5 choices: recycle, reuse, waste less, use less, find substitute or do without

36 14-4 How Long Will Supplies of Nonrenewable Mineral Resources Last? d) Depletion time: time it takes to use up a certain proportion (80%) of the reserves e) This time has several variables (page 361) f) Concern that if all nations used metals at the rate of developed countries, there would not be enough 3) Market prices affect supplies a) Increase in price leads to increased supplies & encourage more efficient uses b) Price reflects supply & demand

37 Fig , p. 361

38 Science Focus: The Nanotechnology Revolution page 362  Nanotechnology, tiny tech  Nanoparticles Are they safe?  Investigate potential ecological, economic, health, and societal risks  Develop guidelines for their use until more is known about them

39 Case Study: The U.S. General Mining Law of 1872 page 363  Encouraged mineral exploration and mining of hard-rock minerals on U.S. public lands  Developed to encourage settling the West (1800s)  Until 1995, land could be bought for 1872 prices  Companies must pay for clean-up now

40 14-4 How Long Will Supplies of Nonrenewable Mineral Resources Last? 4) Is mining lower-grade ores the answer? New methods may allow lower grade ores to be used. However, several factors can limit the mining of these ores 5) Can we extend supplies by getting minerals from the ocean? a) Most elements are in low concentration b) Hydrothermal ore deposits is a potential source b) Manganese nodules on the pacific floor

41 c) Some believe seabed mining would causes less environmenta l harm. However, they are concerned it would destroy seafloor organisms

42 14-5 How Can We Use Mineral Resources More Sustainability? (page )

43 Fig , p. 366

44 Case Study: Industrial Ecosystems: Copying Nature page 366  Mimic nature: recycle and reuse most minerals and chemicals  Resource exchange webs  Ecoindustrial parks  Industrial forms of biomimicry Benefits


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