chapter 16

Chapter 16

Minerals: A nonrenewable

resource

MineralsElements or compounds that occur naturally within the Earth’s crust.Ex- Al, Cu, Mg, Zn, Fe, S, K, P

Sulfides: mineral compounds that contain sulfur in addition to other elements.Oxides: mineral compounds that contain

oxygen in addition to other elements.

MineralsGeneral mining law (1872) encouraged settlement in

western states. Settlers could stake mining

claims on federal land. .

Recently, a Canadian company (ASARCO) paid almost nothing for land worth billions $$$$. (The land has large Cu and Ag

deposits)

http://www.asarco.com/AMDC/home.html

General mining law (1872) has no provisions for:

• Environmental protection•Replacement of topsoil/plants

•Clean-up of tailings•Profit sharing with taxpayers

As a result 19,000km (11,800 mi) of streams totally lifeless.

General mining law (1872)More than 50 of the 100,000 to 500,000 abandoned mines

in the US are designated Superfund sites.

In 2000…

• Congress voted to tighten up on Mining act of 1872.

• George Bush has worked to weaken this legislation…jobs??

Rocks: Naturally formed aggregates (mixtures of minerals).

Ores: contain proportionally large amounts of particular minerals that

can profitably mined.High grade ores: contain large

amount of minerals.Low grade ores: contain relatively

small amounts of minerals.

Metals: minerals that are malleable, lustrous, and good conductors (heat

& electricity).

Nonmetals: minerals that are nonmalleable (brittle), dull, and poor

conductors (heat & electricity).

There are 4 ways in which mineral deposits are

formed…• Magmatic concentration• Hydrothermal processes• Sedimentation• Evaporation

Magmatic Concentration: results in minerals that are malleable, lustrous,

and good conductors (heat & electricity).

As Magma cools it solidifies and separates into layers with the heavier Fe & Mg (Magnesium oxides) rocks

settling towards the bottom.examples: Fe, Cu, Ni, and Cr

Hydrothermal Processes• These processes involve groundwater that has been

heated in the earth.• Water (Polar molecule) is the universal solvent. This

water seeps through cracks and fissures and dissolves certain minerals.

• The dissolving properties of water are better if Cl and F are present. Cl and F often react to create salts. Salts are soluble in water but when salts react with Sufur, metal sulfides are produced and are not soluble in water. These materials are then deposited.

• These processes deposit Au, Ag, Cu, Pb, & Zn.

Sedimentation

• Weathered particles form sediments that are deposited on riverbanks, deltas, & the sea floor.

• Sedimentation has created important deposits of Fe, Mn, P, S, Cu and other minerals.

Evaporation

• Liquid water becomes gaseous and leaves minerals that were in solution behind in the remaining water.

• NaCl (Salt), borax (Sodium borate), K salts, & gypsum have been found in large quantities in rock layers.

MiningSurface Mining: Extraction of

surface minerals.

Subsurface Mining: Extraction of sub surface

minerals.

MiningSurface Mining: more common due

to decreased cost of mineral removal.

Two types: Open-pit mining: Quarries

Strip mining: (strips & spoil banks)

Subsurface Mining:Shaft mines create vertical shafts to

access the ore.Slope mines: create a slanted passage to access minerals.

Processing minerals:

Smelting: Mineral ores are melted at high temperatures to help separate

impurities from liquid (molten) metals.

Blast Furnace

Environmental Issues which result from Mining:

• Destruction of land (22 million acres)• Removal of water from aquifer• Destruction of water quality…tailings (Acid mine drainage)Ex.- Copper Basin in Tennessee

Surface Mining Control and Reclamation Act of 1977

• Requires coal mines to reclaim “derelict” lands

• Makes no provisions for other types of mines

US and Canada have 5% of the world’s population, but consume 25% of its metals.

Mineral Reserves vs.Mineral Resources?

Estimates vary widely!!

Minerals in Antarctica

• Antarctic Treaty of 1961 limits activity to peaceful, scientific work.

• In 1989, the treaty was amended with the Madrid Protocol…No exploration for the next 50 years

How can we preserve or increase our mineral

holdings?

RecyclingConservation

Ocean mining?DematerializationChange mineral

requirements

Dematerialization

The 1st electronic calculator/computerwas built at the University of Pennsylvania in 1946.It weighed 27 metric tons (30 tons), occupied 167m2 of floor space, & required 6 full time technicians to operate it.

What are the 3R’s that promote What are the 3R’s that promote sustainable manufacturing?sustainable manufacturing?