1. Geology and Nonrenewable Minerals
Chapter 15

2. Environmental Effects of Gold Mining
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
Black Hills, S. Dakota

3. Earth’s Major Geological Processes and Hazards
Gigantic plates in the earth’s crust move very slowly atop the planet’s mantle, and wind and water move the matter from place to place across the earth’s surface.
Natural geological hazards such as earthquakes, tsunamis, volcanoes, and landslides can cause considerable damage.

4. The Earth Is a Dynamic Planet
What is geology?
Three major concentric zones of the earth
Core: solid inner part surrounded by a liquid core
Mantle: mostly solid rock
Including the asthenosphere: hot,partly melted rock that flows and can be deformed like plastic
Crust
Continental crust
Oceanic crust: 71% of crust

5. Major Features of the Earth’s Crust and Upper Mantle

6. The Earth beneath your feet is moving…….
Convection cells, or currents : move large volumes of rock and heat in loops within the mantle like gigantic conveyer belts
Tectonic Plates: dozen or so huge rigid plates move extremely slowly atop the denser mantle on hot, soft rock in the underlying asthenosphere
Lithosphere: continental and oceanic crust and the rigid, outermost part of the mantle

7. The Earth’s Crust Is Made Up of a Mosaic of Huge Rigid Plates: Tectonic Plates

8. The Earth’s Major Tectonic Plates
EURASIAN PLATE
NORTH AMERICAN PLATE
ANATOLIAN PLATE
JUAN DE FUCA PLATE
CHINA SUBPLATE
CARIBBEAN PLATE
PHILIPPINE PLATE
ARABIAN PLATE
AFRICAN PLATE
INDIA PLATE
PACIFIC PLATE
PACIFIC PLATE
COCOS PLATE
SOUTH AMERICAN PLATE
NAZCA PLATE
AUSTRALIAN PLATE
SOMALIAN SUBPLATE
Figure 14.4
The earth’s major tectonic plates. See an animation based on this figure at CengageNOW. Question: What plate are you riding on?
SCOTIA PLATE
ANTARCTIC PLATE
Divergent plate boundaries
Convergent plate boundaries
Transform faults
Fig. 14-4, p. 347

9. The Earth beneath your feet is moving ….
Three types of boundaries between plates
Divergent plates –plates move apart
Magma – flows up through the resulting cracks
Oceanic ridge – some of which have higher peaks and deeper canyons than earth’s continents
Convergent plates – oceanic plate collides with a continental plate,
Subduction: the latter rides up over the denser oceanic plate and pushes it down into the mantle
Subduction zone: area where collision and subduction takes place
Trench : forms at the boundary between the 2 converging plates
Transform fault e.g. San Andreas fault: where plates slide and grind past one another along a fracture. Most located on the ocean floor

10. The San Andreas Fault as It Crosses Part of the Carrizo Plain in California, U.S.

11. Some Parts of the Earth’s Surface Build Up and Some Wear Down
Internal geologic processes
Generated by heat from the earth’s interior ,generally build up the earth’s surface in the form of continental and oceanic crust including mountains and volcanoes
External geologic processes
Weathering : driven directly or indirectly by energy from the sun(mostly in the form of flowing water and wind)
Physical, Chemical, and Biological : soil
Erosion
Wind
Flowing water
Human activities
Glaciers

12. Weathering: Biological, Chemical, and Physical Processes

13. Volcanoes Release Molten Rock from the Earth’s Interior
Volcano: magma reaches the earth’s surface through a..
Fissure: central vent or a long crack
Magma
Lava: magma that reaches the earth’s surface. Debris ranging from large chunks of larva rock to glowing hot ash, liquid lava and gases such as water vapor, carbon dioxide and sulfur dioxide . Much of the world’s volcanic activity is concentrated along the boundaries of the earth’s tectonic plates
1980: Eruption of Mount St. Helens
1991: Eruption of Mount Pinatubo: cooled the earth’ average temperature for 15 months
Benefits of volcanic activity: highly fertile soil, creates outstanding landforms (Crater Lake in Oregon)

14. Creation of a Volcano

15. Earthquakes Are Geological Rock-and-Roll Events
Seismic waves
Focus
Epicenter
Magnitude
Amplitude
Richter scale
Insignificant: <4.0
Minor: 4.0–4.9
Damaging: 5.0–5.9
Destructive: 6.0–6.9
Major: 7.0–7.9
Great: >8.0
Foreshocks and aftershocks
Primary effects of earthquakes: shaking, permanent vertical or horizontal displacement of the ground

16. Major Features and Effects of an Earthquake

17. Areas of Greatest Earthquake Risk in the United States

18. Areas of Greatest Earthquake Risk in the World

19. Earthquakes on the Ocean Floor Can Cause Huge Waves Called Tsunamis
Tsunami, tidal wave : generated when part of the ocean floor suddenly rises or drops. Usually occurs offshore in subduction zones.
Detection of tsunamis: by ocean buoys, pressure recorders on the ocean floor which measures changes in water pressure as the waves pass over it; data relayed via satellites tsunami warning systems
December 2004: Indian Ocean tsunami
Magnitude of 9.15
Role of coral reefs and mangrove forests in reducing death toll

20. Formation of a Tsunami and Map of Affected Area of Dec 2004 Tsunami

21. Shore near Banda Aceh,Gleebruk in Indonesia before and after tsunami
Before :June 23, 2004
After: December 28, 2004

22. Gravity and Earthquakes Can Cause Landslides
Mass wasting: detached or loose rock, soil and mud to slide down steep slopes near the shores of oceans or lakes
Slow movement
Fast movement
Rockslides
Avalanches
Mudslides : 1970 – Peru, buried the town of Yungay and killed 17,000 people
Effect of human activities on such geological events:
forest clearing, road building , crop growing, building houses

23. Earth’s Rocks are Recycled……..
The three major types of rocks found in the earth’s crust—sedimentary, igneous, and metamorphic—are recycled very slowly by the process of erosion, melting, and metamorphism.

24. There Are Three Major Types of Rocks
Earth’s crust
Composed of minerals and rocks
Three broad classes of rocks, based on formation
Sedimentary Igneous
Sandstone Granite
Shale Lava rock
Dolomite Metamorphic
Slate Anthracite
Lignite Slate
Bituminous coal Marble

25. The Earth’s Rocks Are Recycled Very Slowly
Rock cycle: the interaction of physical and chemical processes that change rocks from one type to another. Slowest of the earth’s cyclic processes

27. What Are Mineral Resources?
Naturally occurring materials in the earth’s crust that can be extracted and made into useful products in processes that provide economic benefits and jobs.
100 minerals:
fossil fuels(coal)
metallic(aluminum, iron, copper)
non-metallic(sand, gravel, limestone, salt, precious gems)
Mineral deposit – area in which a particular mineral is concentrated.
Ore – metal-yielding material; contains 2 parts: the ore mineral (metal) and waste mineral material (gangue)
High-grade ore – large amount of desired metal
Low-grade ore – small amount of the desired resource

28. Removing Metals from Ores
Nonrenewable – takes so long to be produced
Ore extracted by mining
Ore mineral = desired metal
Gangue - waste material. Removing the gangue from the ores produces tailings. Particles of toxic metals blown by the wind or leached by rainfall can contaminate surface water and groundwater.
Smelting – heating ore in order to separate desired metals. Without proper equipment, releases sulfur dioxide and suspended particles, damage vegetation and acidify soils

29. Extracting, Processing, Using Nonrenewable Mineral and Energy Resources
Life Cycle of a Metal Resource

30. Mineral Use Has Advantages and Disadvantages
Ads: Mine and convert minerals into useful products
Disads: uses enormous amounts of energy, disturbs land, erodes soil, produces solid waste, air and water pollution

31. Ways to Remove Mineral Deposits
Surface mining : shallow deposits removed
mechanized equipment strips away overburden(soil and rock overlay), discarded as waste called spoils
Used to extract 90% of the nonfuel mineral and rock resources and 6% of the coal
Type of surface mining used depends on
Resource
Local topography
Subsurface mining
Deep deposits removed
Used to extract coal and metal ores

32. Types of Surface Mining
Open Pit Mining - machines dig hole and remove ore
Strip Mining - earth movers strip overburden and power shovels remove deposit
Contour Mining - mine coal on hilly terrain. Wall of dirt left in front of a highly erodible bank of soil and rock called highwall
Mountain Top Removal - Appalachian Mountains , draglines, explosives remove top of mountain to expose seams

33. Open-Pit Mine in Western Australia

34. Contour Strip Mining in hilly areas
Undisturbed land
Overburden
Highwall
Coal seam
Overburden
Pit
Bench
Coal seam
Figure 14.17
Natural capital degradation: contour strip mining of coal used in hilly or mountainous terrain.
Contour Strip Mining in hilly areas
Spoil banks
Fig , p. 357

35. Mountaintop Coal Mining in West Virginia, U.S.

36. Mining has Harmful Environmental Effects…….
Scarring and disruption of the land surface
E.g., spoils banks
Large amounts of solid waste (3/4th of all US solid waste)
Toxin-laced mining waste deposited in areas other than mining site .
Loss of rivers and streams – km have been buried
Subsidence - collapse of land

37. Harmful Environmental Effects
Major pollution of water –
Acid mine drainage
Leaching of heavy metals
Oil and chemical spills
Highly toxic cyanide salts are used to extract gold from its ore; leave behind cyanide laden water
Effect on aquatic life –
pH change,
40% of all US watersheds contaminated
Illegal Gold Mine 37

38. Environmental Effects of Gold Mining
Gold producers
South Africa
Australia
United States
Canada
Cyanide heap leaching
Extremely toxic to birds and mammals
Collapse of a dam retaining a cyanide leach pond
Black Hills, S. Dakota

39. Summitville Gold Mining Site in Colorado, U.S.

40. The U.S. General Mining Law of 1872
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

41. LEGISLATION

42. LEGISLATION (cont.)

43. POSSIBLE REMEDIES FOR MINIMIZING EFFECTS OF TOXINS
Buffer/neutralize with alkaline(basic) substances such as limestone (calcium carbonate), sodium hydroxide (NaOH), or ammonia.
Cover tailings to reduce contact with precipitation.
Sedimentation ponds/retention basins or ponds.
Bioremediation by sulfate-reducing bacteria.

44. Ecological Restoration of a Mining Site in New Jersey, U.S.

45. POSSIBLE STEPS TO RESTORING SURFACE-MINED LAND
Re-contouring/regrading land to its original topography.
Replacing and/or adding topsoil/nutrients as needed to improve soil quality or structure
Replanting
native vegetation
fast-growing species
early successional species
Monitor for 5 to 10 years

46. How Long Will Supplies of Nonrenewable Mineral Resources Last?
All mineral resources exist in finite amounts, and as we get closer to depleting any mineral resource, the environmental impacts of extracting it generally become more harmful.
Relatively abundant deposits of iron and aluminum (bauxite)
Scarce - manganese, chromium, cobalt, platinum
An increase in the price of a scarce mineral resource can lead to increased supplies and more efficient use of the mineral, but there are limits to this effect.

47. Uneven Distribution of Minerals
Most of the nonrenewable mineral resources supplied by
Canada
United States
Germany
Russia
South Africa - self sufficient in all key minerals, largest producer of gold, chromium and platinum
Australia
8% of world population, consume 75% of the world’s key metals
China increasing consumption

48. Four Strategic Metal Resources….
Manganese
Cobalt
Chromium
Platinum
US has little or no reserves of these metals which are essential for the country’s economy and military strength
May have to switch to “nano” materials

49. MINERAL PRODUCTION OF SOME NON-FUEL MINERAL RESOURCES

50. The Nanotechnology Revolution
Nanotechnology (tiny tech) - use carbon, oxygen and silicone atoms to create everything from medicines, solar cells to automobile bodies
Currently used in more than 400 items - odor eating socks, wrinkle –free clothes, cosmetics, sun screens
Nanoparticles
Are they safe?
Investigate potential ecological, economic, health, and societal risks
Develop guidelines for their use until more is known about them

51. Economic Depletion of Non- renewable Mineral Resources
Future supply depends on
Actual or potential supply of the mineral
Rate at which it is used
When it becomes economically depleted
Recycle or reuse existing supplies
Waste less
Use less
Find a substitute
Do without

52. MINERAL ORES AND YEARS OF SUPPLY

53. Depletion Curves for a Nonrenewable Resource
Depletion time - time it takes to use up approximately 80% of the reserves of a mineral at a given rate of use

54. Market Prices Affect Supplies of Nonrenewable Minerals
Subsidies and tax breaks to mining companies keep mineral prices artificially low
Does this promote economic growth and national security?
Scarce investment capital hinders the development of new supplies of mineral resources

55. Is Mining Lower-Grade Ores the answer?
Factors limit the mining of lower grade ores
increased cost of mining
limited availability of fresh water
environmental impacts of increased land disruption, waste material and pollution produced during mining and processing
Use microorganisms that can extract minerals “in-place” or “in- situ” mining.
Biomining - genetic engineering techniques used to produce bacteria that can be used to extract a particular metal without disturbing the surrounding environment

56. Extend Supplies by Getting More Minerals from the Ocean…
Mineral resources dissolved in the ocean-very low concentrations, requires more energy and money than they are worth
Only magnesium, bromine and sodium chloride are abundant enough to be extracted profitably
Deposits of minerals in sediments along the shallow continental shelf and near shorelines - sand, gravel,phosphates,sulfur,tin,copper,iron,tungsten,silver, titanium,platinum,diamonds

57. Extend Supplies by Getting More Minerals from the Ocean
Hydrothermal ore deposits : sulfides, zinc, silver, copper precipitate out and build up as mineral deposits
currently costs too much to extract,
disputes over ownership
Metals from the ocean floor - potato sized manganese nodules, cover 25-50% of the Pacific ocean floor
Effect of mining on aquatic life
Environmental impact - sea bed mining ,less impact than land (??)

58. How Can We Use Mineral Resources More Sustainability?
Find substitutes for some scarce mineral resources
materials revolution : silicon, ceramics, plastics
houses made of styrofoam sprayed with ceramic spray called Grancrete, reduces use of timber
high strength plastics and composite materials strengthened by light weight carbon and glass fibers are transforming the automobile and aerospace industries
making plastics requires fossil fuels and oil
Substitution may not always be possible :
platinum, industrial catalyst
chromium : stainless steel

59. We Can Recycle and Reuse Valuable Metals
Recycling
Lower environmental impact than mining and processing virgin materials
Reuse - gold, silver, iron, copper, steel, aluminum, platinum
Recycling aluminum beverage cans and scrap aluminum produces 95% less air pollution, 97% less water pollution and uses 95% less energy

60. There Are Many Ways to Use Mineral Resources More Sustainability
How can we decrease our use and waste of mineral resources?
Pollution and waste prevention programs
3M : Pollution Prevention Pays (3P)
Cleaner production : air pollution 70% lower, saved $750 million in waste disposal and material costs

61. Sustainable Use of Nonrenewable Minerals

62. Industrial Ecosystems: Copying Nature
Mimic nature: recycle and reuse most minerals and chemicals : waste outputs of one organism becomes the nutrient inputs of another
Resource exchange webs : wastes of one manufacturer becomes the raw materials for another
Ecoindustrial parks on brownfields, which are abandoned industrial sites
Industrial forms of biomimicry
Benefits : come up with new environmentally beneficial and less resource-intensive chemicals
Better image among consumers

63. An Industrial Ecosystem in Denmark Mimics Natural Food Web