2 16.1 Minerals and Mineral Resource A. What is a Mineral?Mineral is a naturally occurring, inorganic solid that has a characteristic chemical composition and physical properties.The atoms of minerals are arranged in regular repeating geometric patterns.Native elements are minerals made of only elements (gold, silver and copper)Most minerals are compounds
4 B. Ore MineralsOre minerals are minerals that are valuable and economical to extract.Gangue minerals are minerals that have no commercial value1. Metallic MineralsMetals conduct electricity, have shiny services and are opaqueValuable metallic minerals are native elements such as gold, silver and copper.2. Nonmetallic MineralsNonmetals tend to be good insulators, have shiny or dull surfaces and may allow light to pass through them.Nonmetallic minerals can be native elements or compounds.
6 C. How do Ore Minerals Form? The types of minerals that form depend on the environment in which they form1. Hydrothermal SolutionsHydrothermal solutions are hot subsurface waters that contain dissolved minerals.As they flow through cracks in rocks they dissolve mineralsNew minerals crystallized out of the solutions then fill fractures to form ore deposits called veins2. EvaporitesWater in the seas or lakes evaporates deposits of salts are left behindEvaporates form in arid regions where rates of evaporation are highInclude rock salt and gypsum.
8 D. Mineral Resources and their Uses Some metals can be pounded or pressed into various shapes or stretched very thinlySome are good conductors of heat and electricityAlloys are formed when two or more metals are combinedNonmetals are most widely used minerals in the worldGemstones are nonmetallic minerals prized purely for their beauty, rarity, or durability.
9 Stop here and complete 16.1 active reading worksheet
10 19.2 Mineral exploration and Mining A. Mineral Exploration1st step in finding an ore deposit is exploring rock for mineralization.Planes carry instruments that identify patterns in the land2nd step rock samples are taken from the areas and analyzed to determine ore grade
11 B. Subsurface MiningSubsurface mining is how ore deposits beneath Earth’s surface.Room-and-pillar mining is a common method used to extract coal and salt.Networks of entries (rooms) are cut into a horizontal layer of coal.Between each room is a pillar of coal left to support t the roof.When mining is complete the pillars of coal are removed.
12 1. Longwall MiningLongwall mining is a more efficient way to remove coal form a subsurface seam.A machine (shearer) moves back and forth across the face of a coal seam.The coal is sheared from the surface and falls on a conveyor then transported out of the mine.2. Solution MiningSoluble mineral ores can be removed by solution mining.Hot water is injected into the oar and dissolves it.Compressed air is pumped into the dissolved ore and lifts it to the surface.
13 C. Surface MiningSurface mining methods used when ore deposits are located close to Earth’s surface.Open-pit mining is often used to mine large quantities of near-surfaceOre is mined downward, layer by layer.
14 1. Surface Coal MiningOverburden is rock that covers near-surface coal seams1st step is to remove and set aside the soil2nd overburden is removed by heavy equipments.3rd loaders enter the pit and remove the exposed coal4th once coal is removed the pit is filled with overburden, contoured and covered with the soil
15 2. QuarryingBuilding stones (granite and marble) are mined in quarries.Aggregates (sand, gravel, and crushed rock) are the main products of quarrying.
16 3. Solar EvaporationSolar evaporation is the process of placing sea water into enormous shallow ponds.Sun evaporates the water and increases the concentration of sodium chlorideThis method of salt production is used in areas that receive little rainfall and have high evaporation rates.Solar evaporation is used largely in developing countries and 30% of worlds salt comes from solar evaporation.
17 D. Placer MiningPlacer deposits are minerals that are concentrated by wind and water into surface deposits.Streams transport mineral grains to a point where they fall to the streambed and are concentrated.Stream placers often occur at bends in rivers where the current slows.Gold, diamonds and other heavy minerals are mined by dredging.
18 E. SmeltingSmelting is where crushed ore is melted at high temperatures in furnaces to separate impurities from molten metal.Flux bonds with impurities and separates them from the molten metalMolten metal falls to the bottom of the furnace and is recovered.The Slag (impurities)form a layer on the topGases (sulfur dioxide) are captured so they do not enter the environment
19 F. Undersea Mining Ocean floor contains significant mineral resources Cost and great waters depths at which minerals are found are two reasons undersea mining has not been successful.
21 Stop here and complete the 16.2 active reading worksheet.
22 16.3 Mining Regulations and Mine Reclamation Because of environmental impacts of mining, it is the most heavily regulated industries in the US.Reclaiming the land or returning it to its original condition after mining is a part of every surface coal mining operation.A. The Environmental Impacts of MiningBillions of dollars are spent to clean up abandoned mines.
23 1. Air and Noise Pollution At surface coal mines dust is produced by removing, loading, hauling and dumping soil and overburden.Dust is also produced when ore is blasted apartNoise is created by equipment and blastingMost surface mines are not located near urban populationsRegulations in US forbid mining operations to allow dust or noise t exit the area being mined
24 2. Water ContaminationWater resources can be negatively impacted by miningContainments can wash into streams where they can harm or kill aquatic lifeMinerals that contain a lot of sulfur and react with water to produce dilute sulfuric acid.
25 3. Displacement of wildlife Removing soil from a surface mine site strips away all plant life.With the removal of plants animals will leave the areaWhen the soil is returned to the site different plants and animals may establish themselves.Dredging disturbs river bottoms and destroys aquatic plant live.Disturbance of a riverbed can cause sediments to contaminate a river for up to 10 km
26 4. Erosion and Sedimentation Excess rock from mines is dumped into large piles called dumps.Running water erodes unprotected dumps and may harm water quality and aquatic life5. Soil DegradationSoil at a mine is removed from the uppermost layer downwardIf soils is not removed and stored in separate layers the soil may be nutrient poor when it is reclaimed.Soil rich in sulfur once exposed t water and oxygen release acid.If acidified soil is returned to the mine site it may be difficult for plants to grow.
27 6. SubsidenceSubsidence is the sinking of regions of ground with little or no horizontal movement.Can occur when pillars in a mind collapse or the mine roof or floor failsBuildings, houses, roads, bridges, underground pipelines and utilities may be damaged7. Underground Mine FiresFires in underground coal seams are one of the most serious environmental consequences of coal miningLighting, forest fires and burning trash can cause coal-seams fires.These fires are hard to put out and often left to burn out (which may take decades).They release smoke and gasses that can cause respiratory problems.
28 B. Mining Regulation and Reclamation Mines in US are regulated by federal and state lawsMining company must comply with Clean Water Act and the Safe Drinking Water Act.All mining operations must comply with the Endangered Species Act.
29 1. ReclamationReclamation is the process of returning land to its original or better conditions after mining is completed.The Surface Mining control and Reclamation Act of 1977 (SMCRA) create a program for the regulation of surface coal mining.The act set standards that minimize the effects of coal mining on environment
30 2. State Regulation of Mining Mining companies must obtain permits before miningA bond forfeiture program is where a company must post a funds (a bond) before mining project beginsThe states use the funds to reclaim the sit if the company does not reclaim the site according to the standards.State agencies are responsible for inspecting mines to ensure compliance with environmental regulations.Pennsylvania has large projects to reclaim abandoned mine lands.
31 Stop here and complete 16.3 active reading worksheet.