Mining and Mineral Resources

Minerals and Mineral ResourcesObjectives1. Define the term mineral.2. Explain the difference between a

metal and a nonmetal, and give two examples of each.

3. Describe three processes by which ore minerals form.

•A lot of what you use comes from minerals

•Minerals are mined so can harm the environment

•Resources will not last indefinitely

•What is a mineral?–A naturally occurring, usually inorganic solid that has a characteristic chemical composition, and orderly internal structure, and a characteristic set of physical properties

Table 1. Average Composition of the Crust

Element (Symbol) Weight percent Oxygen (O) 46.Silicon (Si) 27.7 Aluminum (Al) 8.1Iron (Fe) 5.0 Calcium (Ca) 3.6 Sodium (Na) 2.8 Potassium (K) 2.6Magnesium (Mg) 2.1 98.5

–Atoms are arranged in regular repeating patterns

–Most are compounds but some exist as native compounds (gold, silver, copper, …)

•Ore Mineral–Minerals that are valuable and economical to extract•Mining process removed the valuable minerals and the gangue (no commercial value) from the host rock

Common Elements and Their Ore Minerals

Aluminum Gibbsite, boehmite, bauxite

Beryllium Beryl

Chromium Chromite

Copper Bornite, cuprite, chalcocie, chalcoprite

Iron Goethite, hematite, magnetite, siderite

Lead Galena

Manganese Psilomelane, pyrolusite

Mercury Cinnabar

Molybdenum Molybdenite

Nickel Pentlandite

Silver Acanthite

Tin Cassiterite

Titanium Ilmenite, rutile

Uranium Carnotite, urainite

Zinc sphalerite

•Types of Minerals–Metallic

•Conduct electricity, shiny, opaque

–Nonmetallic•Good insulators, shiny or dull surfaces, and transparent or translucent

•Mineral Formation–Depends on the environment determine type of mineral•Metallic min. form below ground when magna cools and hardens

•Hydrothermal Solution. Hot water under ground brings flow through cracks in rocks, dissolving minerals they come in contact; minerals crystallize out and fill cracks. Deposits become veins

•Evaporites. Rivers and streams dissolve salts and carry them to seas and lakes. When the water evaporates the salt is left behind

Uses of important Metallic and Nonmetallic ElementsAl Cans, foil, windows, doors, siding, autos,

aircraft

Cu Cables, wires, electrical, plumbing, coins

Au Computers, communication, spacecraft, dentistry, jewelry

Fe Steel

Lead Batteries, ammunition, glass, ceramics

Si Computer chips, glass, ceramics

Ag Photography, electrical, mirrors, chemistry

Su Sulfuric acid, gun powder, rubber

Ti Jet engines, aircraft, spacecraft, missiles, pigments

Zn Steel coatings, brass, rubber, paints

Mineral Exploration and MiningObjectives1. Describe the manner in which mining

companies explore for new mineral deposits.

2. Describe three methods of subsurface mining.

3. Describe two methods of surface mining.

4. Define placer deposit, and explain how placer deposits form.

5. Describe the steps that take place in smelting an ore.

•Mineral Exploration–Mining companies won’t mine unless the minerals deposit is 100-1000x the concentration of the ordinary rock

•Use instruments that identify gravity, magnetism, radioactivity

•Aircraft, satellites, aerial photos

•Types of Mining–Subsurface mining – mining 50 m or more below the surface•Longwall mining- uses a rotating shearer to remove mineral

http://technology.infomine.com/openpitmine/images

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• http://www.comalco.com/freedom.aspx?pid=260

•Solution mining – hot water is injected into the ore and dissolves it

–Surface Mining•Open pit mining•Surface coal mining•Quarrying•Solar evaporation

–Placer Mining•Surface deposits concentrated by wind and water–Along coastlines–Mined by dredging

–Undersea Mining

–Smelting•Crushed ore is melted at high temperatures in furnace to separate impurities from molten rock

Mining Regulations and Mine ReclamationObjectives1. Describe seven important

potential environmental consequences of mining.

2. Name four federal laws that relate to mining and reclaiming mined land.

3. Define the term reclamation. 4. Describe two ways in which state

governments regulate mining.

•Environmental Impacts or consequences of Mining–Air and noise pollution–Water contamination

•Acid mine drainage – when oxygen and water react with minerals to form sulfuric acid

–Erosion and sedimentation

–Soil degradation •Acidified soil

•Subsidence•Underground mine fires

•Mining Regulations and Reclamation–Mines are regulated by state and federal laws•Clean Water Act•Comprehensive Response Compensation and Liability Act

•Endangered Species Act

–Reclamation – the process of returning land to its original or better condition after mining is completed•Surface Mining Control and Reclamation Act of 1977

–State Regulation of Mining•permits