26 terms

ES Chapter 16 Mining and Mineral Resources

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Mineral
Naturally occurring, usually inorganic solid that has a characteristic chemical composition, an orderly internal structure, and a characteristic set of physical properties. Made up of atoms of a single element. Atoms that make up minerals are arranged in regular, repeating geometric patterns. The arrangements determine the physical properties of minerals. EX: Gold, silver, copper.
Compounds
Atoms of two or more elements chemically bonded together.
Native elements
Gold, silver, copper.
Alloys
When two or more metals combine. Important because they often combine the most desirable properties of the metals used to make them.
Gemstones
Nonmetallic minerals. Prized purely for their beauty, rarity, and durability. EX: Diamond, ruby, sapphire, emerald, aquamarine, topaz, and tourmaline.
Aluminum
...
Mineral exploration
1. Exploring rock for mineralization
2. Planes carrying instruments that identify patterns in gravity, magnetism, or radioactivity fly over and collect these data, as well as images and photographs of an area. These can be used to create a geological map of the surface.
3. Rock samples are taken from the area.
4. The samples are analyzed to determine ore grade
5. If the ore grade is high enough, the companies will drill test holes that help them estimate the three-dimensional extent of the ore. If the ore grade is high enough and the deposit extensive enough, the cost to open a mine may be warranted.
Ore grade
The metal content of an ore.
Subsurface mining
Ore deposits that are usually found 50m or more beneath the earth's surface are mined by this method.
Room and pillar mining
A common method of subsurface mining that is used to extract coal and salt.
Rooms
A network of entries. Between the rooms, pillars of coal are left standing in support of the roof. When the mining of the rooms are done, the pillars are then removed, beginning with the pillars at the farthest point in the mine.
Longwall mining
A machine called a shearer moves back and forth across the face of a coal seam. The wall of the seam called the longwall, may be more than 300m long. As coal is sheared from the face, it falls onto a conveyor. The conveyor transports the coal out of the mine. A row of hydraulic roof supports protects the miners and the equipment. As the shearer advances forward through the coal seam, the mine roof behind the hydraulic supports collapses.
Solution mining
Hot water is injected into the ore and dissolves it. Compressed air is then pumped into the dissolved ore, and air bubbles lift it to the surface.
Surface mining
When ore deposits are located close to the earth's surface.
Open-pit mining
A method that is often used to mine large qualities of near-surface ore. Coal and metals such as copper are mined using this method. The ore is mined downwards, layer by layer. First, explosives are used, if needed, to break up the ore. Then the ore is loaded into haul trucks. The haul trucks transport the ore from the mine. Some ores, such as gold ore, are taken to heap leaching pads. There the gold is extracted from the ore using chemicals.
Overburden
Rock that covered near-surface coal seams.
Surface coal mining
1. Remove and set aside the soil that covered the area.
2. The overburden is removed by heavy equipment in cuts.
3. The pit is refilled with the over burden and contoured.
4. The soul that has been set aside is now laid on top of the overburden.
Aggregates
Crushed rock. Main products of quarrying.
Quarrying
Building stones such as granite and marble are mined in quarries.
Solar Evaporation
Process of placing sea water, which is about 2.7% sodium chloride, into enormous shallow ponds. The sun evaporates the sea water which causes the sodium chloride concentrate to increase. When the concentration of sodium chloride reaches a little over 25 percent, salt crystals begin to form. Then the salt is harvested. A methods of salt production that is used in areas that that receive little rainfall and that have high evaporation rates. Has been used to produce salt for thousands of years.
Placer deposits
Minerals concentrated by wind and water into surface deposits. The most important are stream placers. Streams transport mineral grains to a point where they fall to the streambed and are concentrated. Concentrations occur at places where currents are weak and the dense mineral grains can no longer be carried in the water. May form along coastlines from heavy minerals that wash down to the ocean in streams. These heavy minerals are concentrated by wave action.
Dredge
A floating barge on which buckets fixed on a conveyor are used to excavate sediments in front of a dredge.
Smelting
Crushed ore is melted at high temperatures in furnaces to separate impurities from molten metal. In the furnace, material called a flux bonds with impurities and separates them from the molten metal. The molten metal falls to the bottom of the surface and is recovered.
Acid mine drainage
AMD. The contaminated water that results from this process.
Subsidence
The sinking of regions of the ground with little or no horizontal movement. Occurs when pillars that have been left standing in mines collapse or the mine roof or floor fails.
Reclamation
The process of returning land to its original or better condition after mining is completed.