Transcript 1. ore
The Formation, Mining, and Use of Minerals Chapter 2 Section 3 Pages 12 - 17 Vocabulary: 1. ore 2. reclamation Where Do Minerals Form? P. 12 -13 Minerals form in a variety of environments in the Earth’s crust. The environment in which a mineral forms determines the mineral’s properties. Minerals can form in: 1. evaporating salt water: when a body of salt water dries up, minerals such as gypsum and halite are left behind. 2. metamorphic rocks: when changes in pressure, temperature, or chemical makeup change a rock, metamorphism takes place. Examples include garnet and hemitite. 3. limestones: surface water and ground water carry dissolved materials into lakes and seas, where they crystallize on the bottom. Examples include calcite and dolomite. 4. hot-water solutions: groundwater works its way downward and is heated by magma. It reacts with hot water minerals to form a hot liquid solution. Minerals crystallize out of this. Examples include gold, copper and pyrite. 5. pegmatites: as magma moves upward, it can form teardrop-shaped bodies. These become really large and can form minerals that qualify as gemstones such as topaz and tourmaline. 6. plutons: as magma rises upward through the crust, it sometimes stops moving before it reaches the surface and cools slowly. Mica, feldspar, magnetite, and quartz are examples of minerals formed in this environment. Mining p. 14 -15 1. ore – a natural material whose concentration of economically valuable minerals is high enough for the material to be mined profitably. Ore, a mineral deposit large enough and pure enough to be mined for a profit, can be taken from the Earth in two ways; surface mining and subsurface mining. Surface Mining Subsurface Minng Surface Mining When mineral deposits are located at or near the surface of the Earth, surface mining methods are used to remove the minerals. Surface mines can include open pits, surface coal mines and quarries. Open Pits: Explosives are used as ore is mined downward, layer by layer to break up the ore. Ore, such a gold or copper, is then loaded onto to truck and hauled from the mine for processing. Surface Coal Mines: These are often called strip mines because the coal is removed in strips that may be a wide as 50 meters and as long as 1 kilometer. Quarries: Quarries are open pits that are used to mind building stone, crushed rock, sand, and gravel. In open pit mines, the ore is mined downward in layers. The stair-step excavation of the walls keeps the sides of the mine from collapsing. Giant haul trucks are used to transport ore from the mine. Haul Truck Subsurface Mining Subsurface mining methods are used when mineral deposits are located too deep with in the Earth to be surfaced mined. Subsurface mining often requires that passageways be dug into the Earth to reach the ore. These passageways may be dug horizontally or, if the minerals are deep within the Earth, vertically. Subsurface mining is the removal of minerals of other materials from deep within the Earth. Passageways must be dug underground to reach the ore. Machines such as continuous mining machines are used to mine ore in subsurface mines. 2. reclamation – the process of returning land to its original condition after mining is completed. Responsible Mining p. 15 This area in Colorado has gone through the process of reclamation, restoring what was once an open-pit mine to this area. Mining can destroy or disturb the habitats of plants and animals. Waste products from mining may also get into water sources. The process by which land used for mining is returned to its original state or better is called reclamation. Reclamation of mined public and private land has been required by law since the mid 1970’s. The Use of Minerals p. 16 - 17 Some minerals are of major economic importance. Mineral Copper Uses electrical wire Diamond Jewelry, cutting Tools, drill bits Gold Jewelry, computers Halite Nutrition, highway de-icer Quartz Glass, computer chips Silver Photography, jewelry Gypsum Wallboard, cement Galena Batteries, ammunition Metallic minerals have shiny surfaces, do not let light pass through them, and are good conductors of heat and electricity. They can be strong and do not rust. Examples include gold, silver and copper. Nonmetallic minerals have shiny or dull surfaces, may let light pass through them, and are good insulators of electricity. Examples include gypsum and quartz. Gemstones are also nonmetallic. They are valued for their beauty and rarity rather than usefulness. Color is the most important characteristic of a gemstone. They must also be durable. Quiz Time! 1. How can mining cause water pollution? The waste products from a mine can put pollution into rivers, lakes, and groundwater. 2. _______ is the process of returning land to its original condition after mining is completed. reclamation 3. ______ is the term used to describe a mineral deposit that is large enough and pure enough to be mined for profit. ore 4. Which of the following conditions is NOT important in the formation of minerals? A. presence of groundwater B. evaporation C. volcanic activity D. wind D 5. What are the two main types of mining and how are they different. Surface mining – used when mineral deposits are located at or near the surface of the Earth. Subsurface mining – used when mineral deposits are located too deep within the Earth to be surfaced mined.