1. Minerals and Rock Resources

2. Pegmatite, a very coarse-grained (many over 2 cm) plutonic rock, may yield large, valuable crystals.

3. What is a mineral ore?
Minerals resources usually occur in the Earth’s crust in relatively low concentrations
At these low concentrations, the minerals are almost impossible to extract from the surrounding rocks
In some regions, geological processes have increased the concentration of the minerals
Geological processes include: crystal settling in magma chamber, Kimberlite pipe formation, hydrothermal deposition, evaporation, sedimentary sorting, and leaching /weathering
An ore deposit– rock in which a valuable or useful metal occurs to be economic to mine

4. The Difference Between Rock and Ore: Ore deposits are extreme local enrichments of metal

5. How do you determine how “good” an ore deposit is?
Concentration Factor (CF): CF = Cm/Cmc
Cm = Concentration of the metal in the ore deposit
Cmc = Concentration of the metal in average continental crust
The higher the CF - the richer the ore

6. Concentration Factor Example with chalcopyrite (CuFeS2)
Chalcopyrite is a Copper Ore because it contains more Cu than ordinary crust
Abundance of metal in ore
5 Kg Cu/1000 kg rock=0.485%
Earth’s crust is % Cu, so the concentration factor of this ore deposit is:
0.485% Cu in ore/0.0058% Cu in crust=83.6
(This is 83.6 times more Cu in the chalcopyrite ore than there is in ordinary crust)

7. Approximate Concentration Factors of Selected Metals Necessary before Mining is Economically Feasible

8. Concentration Factors
Minimum concentration factor necessary for economic feasibility is subject to change based on:
Changes in mineral demand
Changes in the price or value of the mineral
If price and demand go up, then rocks with lower concentration factors can be mined

9. Examples of Metals obtained from Ores
Aluminum or Iron – appliances and vehicles
Metals for conductors or semi-conductors
Gems, gold, and silver – jewelry
Lead from galena
Copper from malachite and azurite
Zinc from sphalerite
Many other metals found in rocks

10. Household uses of mineral resources

11. Cost Factors Concentration Factor (CF)
World demand and many market factors
Energy cost
Human/labor cost
Distance to processing or market
Environmental cost - remediation

12. Distribution or ore deposits
Globally, very un-even distribution of ore deposits
Some countries have plenty – export nations
Some countries have none – import nations
Un-even distribution of ore deposit is reason wars are fought

13. Proportions of world reserves of some non-fuel minerals controlled by various nations.

14. Distribution of copper and molybdenum deposits

15. Distribution of base and precious metal deposits
Associated with present
and past subduction zones
and zones of hydrothermal
activity

16. How are mineral ores formed?
Igneous, sedimentary, and metamorphic processes create minerals/rocks
More rarely: igneous, sedimentary, and metamorphic processes create mineral ores by concentration minerals though various processes

17. Types of Mineral Deposits
Igneous Rocks and Magmatic Deposits
Pegmatite: Coarse-grained igneous intrusions
Kimberlite: occurs as pipelike intrusive bodies that originated in the mantle
Igneous rock that is ultramafic (containing very little silica)
Kimberlite represents the world's principal source of diamonds.
Hydrothermal Ores
hydrothermal
Relationship to Plate Margins
Sedimentary Deposits
Banded iron formation (خامات الحديد الطباقية)
Evaporite
Other low-temperature ore-forming processes
Placers
Metamorphic Deposits

18. Pegmatite, a very coarse-grained (many over 2 cm) plutonic rock, may yield large, valuable crystals.
Feldspars are common in Pegmatite (feldspars are used in ceramic industry)
Examples of rarer minerals mined from Pegmatite include tourmaline and berl

19. Igneous- Crystal Settling
Dense minerals settle to the bottom of magma chamber
(Chromium, Platinum, Nickel, Copper, Gold, Magnetite)
Less dense minerals may float to the top

20. Igneous- Disseminated deposits
Disseminated deposits: Mineralized fluid from cooling pluton invades and saturates permeable rock surrounding pluton)
Kimberlite pipes
Long, thin pipeline bodies of igneous rock that originate km deep in mantle
Rapid, explosive rise of magma through crust, punches circular hole and creates a tuff ring
Magma carries pieces of mantle rock (Kimberlite) to surface and sometimes diamonds

21. Hydrothermal Ores
Magmas have water and other fluids dissolved in or associated with them
During the later stages of crystallization, the fluids may escape from the cooling magma, seeping through crakes and pores in the surrounding rocks, carrying with them dissolved salts, gases, and metals.
These warm fluids can leach additional metals from the rocks through which they pass
In time, the fluids cool and deposit their dissolved minerals, creating a hydrothermal ore deposit

22. Hydrothermal Ores
A great variety of metals occur in hydrothermal deposits such as copper, lead, zinc, gold, silver, platinum, uranium, and others

23. Igneous-Hydrothermal deposits
Groundwater flows through rocks heated by igneous magmas
• Heated groundwater dissolves metals, gases, salts from magma and leaches additional metals from rocks it passes through such as copper, lead, zinc, gold, silver, platinum

25. Hydrothermal ore deposits form in various ways
(A) Ore deposition in veins around a magma chamber. Less-concentrated ore is disseminated through the rock as fluids seep outward from magma.
(B) Hydrothermal sulfides permeate (fill, saturate) this basaltic rock. (C) Sulfides can be deposited by hydrothermal circulation around a spreading ridge.

26. Sulfur deposition around a fumarole, Kilauea, Hawaii.
Because sulfur is a common
constituent of magmatic gases
and fluids, the ore minerals are
frequently sulfides
For example, the lead in lead
ore deposits is found in galena
(PbS); zinc, in sphalerite (ZnS);
and copper, in a variety of copper
and copper-iron sulfides (CuFeS2,
CuS, Cu2S, and others)

27. Black smoker is a name given to hydrothermal vents that emit dark clouds
of suspended sulfide minerals.

28. Effects of hydrothermal activity along the East Pacific Rise
Effects of hydrothermal activity along the East Pacific Rise. (A) “The Spire” black smoker vent along the Mid-Atlantic Ridge. Sulfide-rich fluid gushes out of the hot, fresh seafloor rocks at 365oC (nearly 700oF). (B) Sulfides are also being deposited in Red Sea muds.
Sulfide mineral cloud

29. Plate tectonics and ore deposits
Hydrothermal and igneous ore deposits are especially common near plate boundaries

30. Sedimentary- Banded iron formation
Banded iron formation is
layered sedimentary iron
ores
Iron rich layers (predominantly
hematite or magnetite) alternate
(exchange) with silicate-or
carbonate-rich layers

31. Sedimentary- Evaporite Deposits
Form from precipitation of salts (halite, gypsum, borax, etc.) in shallow marine basins or saline lakes

32. Sedimentary- Evaporite Deposits
Rock salt (halite)

33. Other low temperature ore forming processes- Placer Deposits (المتابر)
Streams often deposit sediments well sorted by size and density
The sorting action can effectively concentrate certain weathering-resistant, dense minerals in places along the stream channel
Placer deposits are an accumulation of alluvium containing valuable minerals which are formed by deposition of dense mineral phases in a trap site
When heavy, stable minerals are freed from their matrix by weathering processes, they are slowly washed downslope into streams that quickly winnow the lighter matrix. Thus the heavy minerals become concentrated in stream, beach, and lag (residual) gravels and constitute workable ore deposits.
Minerals that form placer deposits include gold, platinum, cassiterite, magnetite, chromite, ilmenite, rutile, native copper, zircon, monazite, and various gemstones.

34. Other low temperature ore forming processes- - Placer Deposits
(B) Since placer deposits typically occur as loose gravels, mining them can be relatively easy; here, water flowing from a giant nozzle washes gold-bearing gravels to sluices, in the Yukon, Canada

35. Metamorphic deposits
The mineralogical changes caused by the heat or pressure also can produce economic deposits
Graphite (consists of carbon) is usually mined from metamorphic deposits. Graphite is formed by the metamorphism of coal
Asbestos is a general term applied to a group of fibrous silicates that are formed by metamorphism of igneous rocks rich in ferromagnesian minerals, with the addition of water.

36. Mineral and Rock Resources-Examples What is a mineral resource?
A mineral is a naturally occurring, inorganic, homogenous solid with a definite crystalline structure and chemical composition.
A mineral resource is any mineral that we are interested in mining (gold, silver, copper, iron) for human use.

37. Classification of Mineral and Rock Resources (انواع المصادر المعدنية)
Mineral resources are classified into Metallic and Non-Metallic
Metallic mineral resources
Abundant metals – iron, aluminum
Scarce metals: copper, lead, zinc, nickel, cobalt,
Precious metals: gold, silver, or platinum
Non-metallic mineral and rock resources
Sulfur
Halite (rock salt)
Phosphate rock & potassium-rich potash
Feldspar, quartz, diamond, pumice, garnet, corundum – sulfides, lime (calcium carbonate), sulfur, clay, gypsum
Rocks ( e.g. marble, cut granite, crushed stone, sand and gravel)

38. Per-capita consumption of mineral and rock resources in the United States (2002)

39. Per-capita aluminum consumption in more- and less-developed countries.

40. Mineral Supply and Demand
Global demand is always growing
Growth in worldwide demand is about 2% per year: pre-World War II
About 10 % per year: World War II to mid-1970’s
Demand is fluctuating now
U.S. Mineral Production and Consumption
See Figure 12.11, Table 12.1, and Figure 12.13
U.S. population is only 4.5% of the world, yet we use 30% of its mineral resources.

42. United States share of global consumption of selected materials.

43. World Mineral Supply and Demand
World demand is always fluctuating
Commodities do not follow fluctuating trends
Mineral reserves eventual will be depleted
Import/export relationships will fluctuate
Technology often allows more access to difficult or low grade ore deposits
Future mineral-resource shortages will occur and cause international tension

45. Minerals for the Future: Some Options Considered
Consider controlling consumption rates
Reduce the consumption rates
Hold these consumption rates steady
Carefully consider the facts:
Globally the less developed nations are striving to achieve comparable standards of living as the technologically advanced countries enjoy
Countries that have the fastest-growing populations are not well endowed with mineral deposits and are the less developed countries of the world!

47. Prospecting and Exploration
Geochemical Sampling
Electrical Sounding Ground-Penetrating Radar
Seismic Methods
Reflection - Detailed but Expensive
Refraction - Cheap but Not Detailed
Core Sampling and Well Logging
Satellite and Aerial Photography
Remote Sensing
Geological Mapping
Magnetic Mapping
Gravity Mapping
Radioactivity Mapping

48. New Methods in Mineral Exploration
Fact: the economically easy and profitable deposits are being depleted
Geophysics is a useful aid to locating new deposits
Rocks and minerals vary in density, and in magnetic and electrical properties, so changes in rock types or distribution below the earth’s surface can cause small variations in gravitational or magnetic field measured at the surface, as well as in the electrical conductivity of the rocks
Gravity survey
Magnetic survey
Electrical property survey
Geochemical survey and prospecting is an increasingly popular exploration tool
Remote sensing is expanding into exploration strategies

49. Groundwater sampling can detect trace metals in concentrations as low as a few parts per trillion, even low-solubility metals like gold can thus be detected down the flow path from an ore deposit, and mapping anomalies helps locate it.

50. Remote Sensing Sophisticated but valuable exploration tools
Useful to detect, record, and analyze energy emitted off the earth
Aerial photography
Satellites
Space shuttle, and other manned missions
Remote sensing is backed up by ‘ground truth’ activities
old fashioned geologic mapping
Advances in the geological sciences are directed toward intigration of remote sensing, geochemistry, and geophysics

51. Remote Sensing

52. Landsat satellite images may reveal details of the geology that will aid in mineral exploration. Vegetation, also sensitive to geology, may enhance the image. (A) View of South Africa, dry season. (B) Same view, rainy season. Recognizable geologic feature include a granite pluton (round feature at top left, which is approximately 27km, and folded layers of sedimentary rock (below).

53. Data from the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) make prospecting much simpler. The left-hand image of Cuprite, Nevada, in true color, reveals little about mineral distribution. Central image reveals distribution of hydroxide, carbonate, and sulfate minerals, some associated with gold in the region. Right image distinguishes among different iron-bearing minerals, refining understanding of geology.

54. Marine Mineral Resources
The sea may provide partial solutions to some mineral shortages
Sea water contains abundant dissolved minerals (halite, or sodium chloride) and many useful element such as copper and gold
Most extraction techniques currently used are energy intensive and expensive
Hydrothermal ore deposits along seafloor spreading ridges are a possible source of many materials
Currently, they are too deep - of limited benefit. However, the metal-rich muds of the Red Sea contain sufficient concentrations of such metals as copper, lead, and zinc
The marine mineral resource having the greatest potential for exploitation in the near future is manganese nodules
Manganese nodules are widely distributed on the ocean floors; a promising solution.
Manganese nodules are lumps to about 10 cm in diameter, composed mostly of manganese minerals. They also contain lesser amount of copper, nickel, cobalt, platinum, and other metals.
Many political, environmental, and legal obstacles must be overcome before they can be mined

55. Manganese nodules on the floor of the northeast Atlantic Ocean.

56. Conservation of Mineral Resources
Overall need for mineral resources is growing – must reduce this expansion
Alternatives: Some mineral resources may be substituted by other, more abundant resources
Plastics replacing automobile parts
The most effective way to extend mineral resources may be through Recycling – many metals are successfully recycled
More recycling is required
Not all commodities are easy to recycle
Measures to reduce demand must be the key

57. Growth in consumption of nonfuel organic (mainly plastic) and inorganic (mineral) materials.

59. Impacts of Mining Activities
Mining and mineral processing activities have the potential to produce adverse impacts on the environment.
Very stressful to the environment
Must be carefully planned
Must be safe to miners and their neighbors
Must be contained – water and air pollution is a major problem

60. Problems of Mining Safety Mine Wastes Pollution Dust Noise
Economic Impact
"Boom and Bust" Cycles
Environmental Problems
Exploration
Construction and Operation
Waste Disposal
Sulfur (H2 SO4 )

61. Impacts of Mining Activities
Mining and mineral processing activities have the potential to produce adverse impacts on the environment.
Impacts on the land
Impacts of the air
Impacts on the water

62. Sub-surface mining activities sometimes affect the earth’s surface
Sub-surface mining activities sometimes affect the earth’s surface. Collapse of land surface over old abandoned copper mine in Arizona.

63. The world’s largest open-pit mine: Bingham Canyon, Utah.

64. Spoil banks, rainbow coal strip mine, Sweetwater County, Wyoming.

65. Strip-mining and land reclamation –Revegetation of un-graded spoils at Indian Head mine is slow.

66. Strip-mining and land reclamation: Reclaimed portion of Indian Head mine one year after seeding.

67. Impacts on air Increase amounts of dust and soil in the atmosphere
Emission of gases during the process of smelting and chemical treatment of ore depositions such as Carbon oxides, Nitrogen oxides, Sulfur oxides, Organic matter

68. Sulfur
Present in sulfide ores, pyrite or organic sulfur in coal, organic sulfur in petroleum
Smelting or burning create SO2
2SO2 + O2  2SO3
H2 O + SO3  H2 SO4

69. Sulfuric Acid Contributor to Acid Rain
Neutralized by carbonates and mafic igneous rocks
Worst in granitic bedrock
Weakens tailings piles, slopes, dams
Acidifies surface water
Contributes to dissolved metals

70. Mineral Processing Mineral extraction is environmental hazardous
Processing generally involves finely crushing or grinding the ore
The fine waste material is placed in tailings
Tailings: The piles of crushed waste rock created as a by-product of mineral processing
The tailings are exposed to wind and weather
Rapid weathering of the tailings may leach out harmful elements such as mercury, arsenic, cadmium, or uranium
The surface and subsurface water systems are too often contaminated
Chemicals used in ore extraction must be controlled and not just dumped because they are often hazardous. For example, cyanide is commonly used to extract gold from its ore
Smelting to extract metals from ores may release arsenic, lead, mercury, and other potentially toxic elements along with exhaust gases and ash

71. As the Bingham Canyon mine is approached, huge tailings piles are silhouetted against the mountains

72. Impacts of water
The waste water coming from the mines and ore treatment stations contain metals such as Cd, Cu, Pb, Ni, Hg, etc
These water also contain organic compounds and hazardous acids
Drinking water and surface water pollution