ENV 101 Ch12 lecture ppt_a

1. 12-1
Environmental
Geology
James Reichard
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. 12-2
Chapter 12
Mineral and Rock Resources
© Neil Beer/Getty Images

3. 12-3
Underground Halite Mine
Ohio Department of Natural Resources; (inset): © Salt Institute
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4. 12-4
Mohs
b: U.S. Navy photo by Journalist 1st Class Mark H. Overstreet (RELEASED)
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5. 12-5
Resources
TABLE 12.1 Average yearly per capita consumption rates of various
mineral resources in the United States.
Mineral
Resource
U.S. Yearly Per Capita
Consumption
Percentage of
All Mineral
Resources
Nonmetals Sand, gravel, and
crushed stone
15,892 lb (7,215 kg) 87%
Nonmetals Cement 616 lb (280 kg) 3.4%
Nonmetals Salt 422 lb (192 kg) 2.3%
Nonmetals Phosphate rock 212 lb (96 kg) 1.2%
Nonmetals Clays 145 lb (66 kg) 0.8%
Metals Iron 330 lb (150 kg) 1.8%
Metals Aluminum 66 lb (30 kg) 0.36%
Metals Copper 13 lb (5.9 kg) 0.071%
Metals Lead 11 lb (5.0 kg) 0.060%
Metals Zinc 7 lb (3.2 kg) 0.038%
Metals Manganese 6 lb (2.7 kg) 0.033%
All other minerals 592 lb (269 kg) 3.2%
Total 18,312 lb (8,314 kg) 100%
Source: Minerals Education Coalition, 2015.
Copyright © McGraw-Hill Education. Permission required for reproduction or display.

6. 12-6
Economic Mineral Deposits
Ore deposits
• High grade
• Low grade
Reserve
• Economic
• Marginally economic
• Sub economic

7. 12-7
Resources & Reserves
Identified
deposits
Undiscovered
deposits
Known mining
areas
Undiscovered
deposits
Unknown mining
areas
Economic Reserves
Hypothetical
resources
Speculative
resources
Marginally
economic
Marginal
reserves
Hypothetical
resources
Speculative
resources
Subeconomic
Subeconomic
resources
Hypothetical
resources
Speculative
resources
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
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8. 12-8
Geology of Mineral Resources (1)
Igneous Processes
• Diamond pipes (Kimberlite)
• Intrusive deposits
• Layered deposits
• Hydrothermal deposits
• Disseminated deposits
• Massive sulfide deposits
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9. 12-9
Intrusive Deposits
b: © David Waters, Oxford University
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10. 12-10
Hydrothermal Deposits
© Fernando Tornos, Instituto Geológico y Minero de España
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11. 12-11
Massive Sulfide Deposits
NOAA
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12. 12-12
Geology of Mineral Resources (2)
Metamorphic processes
• Regional metamorphism
• Contact metamorphism
a: USGS; b: © Jim Reichard
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13. 12-13
Contact Metamorphism
© Jim Reichard
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14. 12-14
Geology of Mineral Resources (3)
Sedimentary processes
• Placer deposits
• Residual weathering products
• Banded iron deposits
• Evaporates
• Phosphorites

15. 12-15
Placer Deposits
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16. 12-16
Mining & Processing of Minerals (1)
Mining Techniques
• Surface mining
• Open pit
• Strip
• Underground
• Placer

17. 12-17
Asbestos
USGS
© Hulton-Deutsch/Corbis
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18. 12-18
Weathering of hydrothermal
veins
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19. 12-19
Evaporate deposits (1)
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20. 12-20
Evaporate deposits (2)
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21. 12-21
Evaporate deposits (3)
© R. Douglas Ramsey, Utah State Univ., Remote Sensing and GIS Lab; (inset): Bureau of Land Management
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22. 12-22
1880s Gold mine
© Jim Reichard
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23. 12-23
Open Pit Mining: BIF
a: © Jim Reichard; b: © Jim Wark/Airphoto
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24. 12-24
Strip Mine
a: © Glow Images; b: © West Virginia Office of Miner’s Health, Safety, and Training
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25. 12-25
Underground Mining
(inset): © Digital Vision/Punchstock
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26. 12-26
Hydraulic mining
California Geological Survey Library
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27. 12-27
Mining & Processing of Minerals (2)
Mineral processing
• Physical separation
• Smelting
• Leaching
(top): Courtesy of Barrick Gold Corporation; (bottom left): © Doug Sherman/Geofile; (bottom right): Southern Peru
Earthquake Geo-Engineering, Extreme Event Reconnaissance (GEER) team
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28. 12-28
Disseminated copper deposits (1)
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29. 12-29
Disseminated copper deposits (2)
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30. 12-30
Supply of Mineral Resources (1)
• Meeting future demand
• Recycling
• Reusing
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31. 12-31
Supply of Mineral Resources (2)
TABLE 12.4 World mineral production and projected life of estimated reserves.
Reserves represent mineral deposits that are economical to extract under current
conditions.
Mineral
Production
(thousands of metric
tons)
Reserves (thousands
of metric tons)
Estimated Life of
Reserves (years)
Iron ore 3,320,000 190,000,000 57
Aluminum ore
(bauxite)
274,000 28,000,000 102
Phosphate rock 223,000 69,000,000 309
Gypsum 258,000 not available not available
Chromium 27,000 >480,000 >18
Copper 18,700 720,000 39
Manganese 18,000 620,000 34
Zinc 13,400 200,000 15
Copyright © McGraw-Hill Education. Permission required for reproduction or display.

32. 12-32
Supply of Mineral Resources (3)
TABLE 12.4 World mineral production and projected life of estimated reserves.
Reserves represent mineral deposits that are economical to extract under current
conditions.
Mineral
Production
(thousands of metric
tons)
Reserves (thousands
of metric tons)
Estimated Life of
Reserves (years)
Titanium
concentrates
6,090 790,000 130
Lead 4,710 89,000 19
Nickel 2,530 79,000 31
Tin 294 4,800 16
Cobalt 124 7,100 57
Silver 27 570 21
Gold 3.0 56 19
Platinum group 0.39 66 171
Source: Data from U.S. Geological Survey Mineral Commodity Summaries, 2016.
Copyright © McGraw-Hill Education. Permission required for reproduction or display.

33. 12-33
Environmental Impacts & Mitigation (1)
• General Mining Act 1872
• Clean Air Act 1970
• Clean Water Act 1972
b: US Environmental Protection Agency
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34. 12-34
Environmental Impacts & Mitigation (2)
Heavy metals and acid drainage
A Silverton, Colorado B Jerome, Arizona
a: Philip L. Verplanck, USGS; b: © Jim Wark/Airphoto
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35. 12-35
Environmental Impacts & Mitigation (3)
• Processing of ores
• Collapse and subsidence
• Abandon mine hazards USGS
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36. 12-36
Abandoned mine
© Doug Paddock
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37. 12-37
Remediation of acid mine
drainage
© IntraSearch Inc
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38. Appendix of Image Long
Descriptions

39. Underground Halite Mine Long Description
Mineral resources include a variety of different rocks and minerals. This underground mine is in a
layered sedimentary deposit composed almost entirely of the mineral halite. Finely ground halite is
used as common table salt, whereas coarsely ground halite (inset), called rock salt, is used for de-
icing roadways in the winter.
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40. Mohs Long Description
A graph comparing the quantitative and qualitative hardness of common minerals illustrates the vast
difference in hardness between diamond and the next hardest mineral, corundum. Diamonds are well
known as gemstones, but their greatest use is in cutting tools (B), where their extraordinary hardness
allows humans to cut through any type of material.
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41. Resources & Reserves Long Description
Mineral resources that have been identified and are profitable to mine are called reserves. Those
believed to exist in areas of known deposits but yet to be discovered are considered hypothetical
resources; all other mineral resources are speculative.
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42. Geology of Mineral Resources (1) Long Description
Diamonds form in the upper mantle under conditions of high temperature and pressure, and are then
carried to the surface by magma. Near the surface the highly pressurized magma explodes violently,
creating a pipe-shaped crater. Diamonds are found in the volcanic rocks filling the crater, in ejected
material, and in nearby stream gravels.
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43. Intrusive Deposits Long Description
Dense minerals that crystallize early in the cooling process can settle to the bottom of a magma
chamber and form a layered ore deposit (A). The photo (B) shows layers of chromium-rich minerals
that are part of a layered intrusion in Bushveld, South Africa.
In the later stages of cooling, a magma chamber consists mostly of mineral crystals, with the
remaining magma residing between the crystals. This residual magma is enriched with certain
elements that can form valuable mineral deposits if injected into surrounding rocks, forming small
intrusive bodies called pegmatites.
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44. Hydrothermal Deposits Long Description
Vein and disseminated deposits result when hot, mineral-rich fluids chemically react with minerals in
an igneous intrusion and surrounding rocks, and then transfer elements within a zone around the
igneous intrusion. The photo shows a vein deposit containing valuable tungsten and tin minerals in a
Portuguese mine.
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45. Massive Sulfide Deposits Long Description
Massive sulfide deposits (A) form when hydrothermal fluids discharge from mid-oceanic ridges and
then mix with cool seawater. Here metallic ions bond with sulfur, forming sulfide minerals that
eventually accumulate on the seafloor. Note how heat convection pulls cold seawater into the ridge,
where it reacts chemically with basalt to form hydrothermal fluids. Photo (B) shows sulfide minerals
precipitating as hydrothermal fluids escape from vents on the seafloor.
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46. Geology of Mineral Resources (2) Long Description
Slate (A) forms when shale undergoes regional metamorphism. Because slate breaks into thin sheets
that are hard and durable, it has long been used for roofing shingles (B) and flooring tiles.
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47. Contact Metamorphism Long Description
A diagram shows magmatic heat and hydrothermal fluids that commonly create a zone of altered
rocks surrounding an intrusion in which ore minerals are deposited. Some rock types are more
reactive than others, and thus have wider alteration zones and accumulate different types of minerals.
A photograph shows a marble alteration zone surrounding a basaltic intrusion into limestone beds in
Glacier Park, Montana.
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48. Placer Deposits Long Description
Stream placers form when weathering liberates valuable minerals from a primary ore deposit; erosion
then carries the minerals to a stream where they become concentrated through hydraulic sorting. By
following traces of gold in the sediment upstream through the drainage system, prospectors could
sometimes locate the primary deposit, referred to as the mother lode.
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49. Asbestos Long Description
Photograph taken with an electron microscope showing needle-like fibers of the asbestos mineral
called anthophyllite. Asbestos fibers can easily become lodged in lung and stomach tissue, but cannot
be broken down chemically, leading to scarring of the lungs and fatal lung and stomach cancers.
Photo showing World War II British firefighters training in asbestos suits.
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50. Weathering of hydrothermal veins Long Description
The weathering of hydrothermal veins causes sulfide minerals to break down, allowing water to carry
metallic ions downward, where they recombine to form more stable minerals. This commonly results
in two enriched ore deposits, one in the oxidized zone above the water table and the other in the
reduced zone below, where oxygen levels are low. A low-grade deposit of residual iron minerals lies
at the surface, which helps prospectors locate the underlying enriched zones.
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51. Evaporate deposits (1) Long Description
A map shows both marine and freshwater evaporite deposits in the United States. A pie chart shows
marine deposits consist chiefly of salts based on chloride and sulfate ions, which are the dominant
negatively charged ions in seawater.
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52. Evaporate deposits (2) Long Description
Evaporite deposits form when surface-water bodies undergo evaporation, increasing salinity to the
point where dissolved salts precipitate and fall to the bottom to form layers of salt. Around 400 million
years ago a restricted inland sea over much of the present state of Michigan underwent subsidence
and intense evaporation, resulting in thick evaporite and reef limestone deposits that are currently
being mined.
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53. Evaporate deposits (3) Long Description
Satellite photo of the Great Salt Lake in Utah. This lake (shown in black) represents the remains of a
large body of freshwater that once occupied a series of tectonic valleys. White indicates areas where
the lake has completely evaporated, leaving vast salt deposits on the now exposed lake bed.
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54. 1880s Gold mine Long Description
Photo shows the trace of a gold-bearing hydrothermal vein that was mined in the late 1800s in
Central City, Colorado. Mining began as a surface operation, but later developed into an underground
mine as the ore body was followed into the subsurface. Note the piles of mine tailings (waste
material) along the trace of the vein.
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55. Open Pit Mining: BIF Long Description
Banded iron deposits (A) are believed to have formed between 2.6 and 1.8 billion years ago when
free oxygen became abundant in the atmosphere. Photo showing gray bands of the iron mineral
hematite separated byalternating layers of red, fine-grained chert (SiO2)—note that the layers have
been deformed since they were deposited. Photo (B) shows a large open-pit iron mine in the Upper
Peninsula of Michigan.
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56. Strip Mine Long Description
Photo (A) showing a strip mine in Illinois where a layer of sedimentary overburden is being removed
by a spinning bucket excavator and crane. Layers are also commonly scraped up by a large bucket
(B) that is pulledalong the ground, and then dumped into large trucks.
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57. Underground Mining Long Description
Underground mining involves blasting shafts and horizontal tunnels to access mineral deposits.
Although safety has greatly improved, surface mining is generally preferred over underground mining
as it presents fewer hazards and lower operating costs.
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58. Hydraulic mining Long Description
Hydraulic mining was developed to facilitate the removal of gold-bearing placers from terraces. An
elevated flume was used to collect water from upstream, which was then forced through nozzles to
create a high-pressure stream. The sediment on the terraces was washed into sluices where the gold
was separated hydraulically. Photo from 1890 showing hydraulic mining in Nevada County, California,
in apparent violation of the 1884 ban of the practice.
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59. Mining & Processing of Minerals (2) Long Description
Cross-sectional view of a cyanide heap-leaching system for extracting heavy metals from crushed ore.
Applied to a pile of ore, a cyanide solution percolates and chemically dissolves metallic ions from the
ore minerals. Leachate collected from the bottom of the pile is sent to a processing plant where the
metals are chemically removed. A synthetic liner is used to keep cyanide from escaping into the
environment.
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60. Disseminated copper deposits (1) Long Description
Disseminated copper deposits are unevenly distributed around the world because they are associated
with igneous intrusions and tied to plate tectonics. Note how some of these deposits closely
correspond to the convergent plate boundaries along the Pacific coasts of North and South America.
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61. Disseminated copper deposits (2) Long Description
List of selected mineral resources and the percentage of each that the United States imports (green
denotes strategic minerals). Some minerals are imported simply because it is less expensive than
mining existing U.S. deposits.
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62. Supply of Mineral Resources (1) Long Description
Growth in the yearly consumption of minerals and other materials in the United States from 1900 to
2006. Note the correlation between economic activity and resource consumption.
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63. Environmental Impacts & Mitigation (1) Long Description
(B), causing health and safety concerns. After 4 days, the plume had passed the nearby city of
Durango and pollutant levels soon returned to normal. Concerns remain about the heavy metals that
precipitated out of the water and accumulated on the riverbed.
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64. Environmental Impacts & Mitigation (2) Long Description
Leachate draining from underground mines and from beneath tailings is commonly highly acidic and
laden with heavy metals due to the chemical interaction of water and sulfide minerals. Dissolved iron
quickly precipitates to form iron oxides, giving impacted streambeds a characteristic reddish or
yellowish color (A), whereas a bluish or greenish color from copper precipitates (B) is less common.
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65. Environmental Impacts & Mitigation (3) Long Description
Aerial photo showing numerous pits on the land surface that were caused by the collapse of shallow
underground coal mines in Wyoming.
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66. Abandoned mine Long Description
Abandoned mines, such as the vertical shaft shown here at a long-abandoned site in New Jersey,
pose deadly hazards to humans and animals. Note that the fence was erected by state officials at
taxpayers’ expense.
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67. Remediation of acid mine drainage Long Description
Remediation of acid mine drainage includes neutralizing the acid by letting it first react with crushed
limestone, followed by having the leachate flow through a series of constructed wetlands where
dissolved oxygen is removed. Here heavy metals are removed via plant uptake and by precipitation
under the reducing conditions.
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