Mineral Resources and Environment

Mineral Resources – elements, compounds, minerals, or rocks concentrated in a form that can be extracted to obtain a usable commodity

Reserves – that portion of a resource that is identified and currently available (i.e. from which usable materials can be legally and economically extracted at the time of evaluation).

Minerals and Human Use

Categories:

1. Metal Production & Technology

2. Building Materials

3. Minerals for Chemical Industry

4. Minerals for Agriculture

Mineral Products in a Typical Home

Building materials Sand, gravel, stone, brick (clay), cement, steel, aluminum, asphalt, glass

Plumbing and wiring materials Iron and steel, copper, brass, lead, cement, asbestos, glass, tile, plastic

Insulating materials Rock, wool, fiberglass, gypsum

Paint and wallpaper Mineral pigments (such as iron, zinc, and titanium) and fillers (talc and asbestos)

Plastic floor tiles, other plastics Mineral fillers and pigments, petroleum products

Appliances Iron, copper, and many rare metals

Furniture Synthetic fibers from coal and petroleum ; steel springs; wood

Clothing Natural fibers grown with mineral fertilizers; synthetic fibers

Food Grown with mineral fertilizers; processed and packaged

Drugs and cosmetics Mineral chemicals

Other items Windows, screens, light bulbs, porcelain fixtures, china, utensils, jewelry: all made from mineral resources

Mineral Depletion CurvesBasic problem w/ availability of resources is not exhaustion, but cost of maintaining adequate reserves. At some pt., cost of mining exceeds value of the resource.

Options: find more, find a substitute, recycle/reuse what we have, use less and increase efficiency of use, do without

Choice depends on: Economics, Social factors, Environmental factors

Hypothetical Depletion Curves:

1. Rapid consumption‑‑the most common pattern except for precious metals (PGM)

2. Consumption with conservation

3. Consumption, conservation, and recycling

U.S. per Capita Consumption

• Crushed Stone

• Sand and gravel

• Salt

• Gypsum

• Phosphate

• Potash

• Iron

• Aluminum

• Zinc

• Lead

• Copper

• 4.6 tons

• 3.2 tons

• 396 pds

• 206 pds

• 374 pds

• 48 pds

• 570 pds

• 48 pds

• 11 pds

• 11 pds

• 20 pds

Rates of Use Fe and Na‑‑very high, about 1 billion tpy

N,S,K, and Ca‑mod high as fertilizers‑‑10 to 100 mtpy

Zn, Cu, Al, and Pb‑‑3 to 10 mtpy

Au and Ag about 10,000 tpy

Reliance on ImportsArsenic 100% Chile, France, Mexico

Bauxite 100% Australia, Guinea, Jamaica

Columbium 100% Brazil, Canada, Germany

Graphite 100% Mexico, China, Brazil

Manganese 100% S. Africa, France, Gabon

Mica 100% India, Belgium, Brazil

Strontium 100% Mexico, Spain, Germany

Thallium 100% Belgium, Japan, UK

Gems 98% Israel, Belgium, India

Platinum 94% S. Africa, UK, FSU

Geology of Mineral Resources

• Aspects and processes of the geologic cycle are responsible for producing local concentrations of minerals

• Genesis of Common Mineral Resources

– Plate tectonics and minerals

– Mobilization of elements at convergent boundaries due to partial melting (Hg in volcanic rocks)

• Concentration

– Ore = rock body containing valuable elements/metals that can be extracted

– Concentration factor = ratio of necessary concentration (in ore) for profitable mining to average concentration in Earth’s crust

Plate Tectonics and Minerals•Plate boundaries are related to origin of iron, gold, copper, and mercury ore deposits

•Metallic ore deposits & divergent plate boundaries: circulation of water through fractured, basaltic rock concentrates metallic sulfides as precipitates

•Convergent plate boundaries concentrate metallic ores through partial melting of oceanic lithosphere at a subduction zone – high P & T releases metals from melts, concentrating them.

Mercury Deposits Example

Geology of Mineral Resources

•Igneous processes

–Kimberlite – diamond xtals in coarse grained igneous rock, originally formed at high P (deep) and have been moved to surface

–Crystal settling

–Late magmatic

–Hydrothermal (hot water) ore deposits

•Metamorphic processes

–Contact metamorphism

–Regional metamorphism

Geology of Mineral Resources

• Sedimentary processes

– Processes

• Transport

• Separation by size, shape, and density

– Materials

• Sand and gravel‑old rivers, beaches, and glacial deposit

• Placer deposits‑gold and diamonds; separated by density from running water and on beaches

• Evaporites‑‑seas that are separated or in internal drainage basins

– Marine (K and Na, gyp, anhydrite)

– Non‑marine (CO3, sulfates, borate, nitrate, I, and Br)

– Brines (Br, I, CaCl2, Mg)

– Salt domes‑‑for salt, sulfur, and oil; potential sites for radioactive waste