Minerals Elements 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.
Minerals General 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. Superfund
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 CrFe, 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.
Mining Surface Mining: Extraction of surface minerals. Subsurface Mining: Extraction of sub surface minerals.
Mining Surface 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.
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? Recycling Conservation Ocean mining? Dematerialization Change mineral requirements
Dematerialization The 1 st electronic calculator/computer was built at the University of Pennsylvania in 1946. It weighed 27 metric tons (30 tons), occupied 167m 2 of floor space, & required 6 full time technicians to operate it.