Unit 4 ch 16 s2 mineral exploration & mining


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  • Middle picture is the shearer scraping a coal seam.Bottom picture is the hydraulic roof support
  • Cyanide is very poisonous but does not accumulate in ecosystems like mercury which is probably why it is used.
  • This would make an awesome Transformer!
  • Small picture is talc quarry in France. For making talcum powder.
  • Unit 4 ch 16 s2 mineral exploration & mining

    1. 1. Mining & Mineral ResourcesChapter 16, Section 2: Mineral Exploration & Mining Standards: SEV4a, b, e
    2. 2. What are the steps in harvesting minerals? Prospecting- finding places where ores occur Mine exploration & development- learn whether ore can be extracted economically Mining- extract ore from ground Extraction- separate ore minerals from other mined rock Smelting & refining- extract pure mineral from ore mineral (get the good stuff out of waste rock) Transportation- carry mineral to market Marketing & sales- find buyers & sell the mineral
    3. 3. How do we know where mineral deposits are located? Airplanes can carry instruments that detect  Patterns of gravity Images of the Saline Valley in California.  Magnetism Left picture- red indicates trees, white  Radioactivity indicates snow Data is collected, satellite images are Middle picture- short wavelengths used taken, and a geologic map is created. to identify types of rocks Right picture- thermal infrared used to Rock samples are taken & analyzed for identify types of rocks that contain their content & grade valuable minerals. Red indicates quartz Test holes are drilled to create a 3D estimate of the extent of the ore This will tell the driller if the amount and grade of ore is high enough to warrant the cost of opening a mine. How Much Does a Mine Cost?
    4. 4. 3 Types of MiningA. Subsurface miningB. Surface miningC. Placer mining
    5. 5. A. What is subsurface mining? Mining of ore deposits 50m or more below Earth’s surface. (This is as long as an Olympic size pool) 3 types of subsurface mining: 1. Room & Pillar mining 2. Longwall mining 3. Solution mining
    6. 6. 1. Room & Pillar Mining Coal & Salt can be mined this way “Rooms” are cut into a coal seam. Coal seam is a long, wide, layer of coal. The “walls” of the room act as pillars to prevent collapse. After all rooms of coal removed, the pillars are taken down starting with farthest away.
    7. 7. 2. Longwall mining A shearer machine moves back and forth along the coal seam. Sheared coal drops onto a conveyor belt and exits the mine Hydraulic roof supports are used to prevent collapse
    8. 8. 3. Solution Mining Potash, salt, sulfur are soluble in water Hot water is injected into ore Ore is dissolved Removal of ore from water:  Compressed air pumped into dissolved ore and ore trapped in air bubbles that rise to surface… or…  Water evaporates from dissolved ore leaving ore behind.
    9. 9. B. What is surface mining? Used when ore deposits are located close to Earth’s surface 3 types 1. Open Pit Mining 2. Quarrying 3. Solar Evaporation
    10. 10. 1. Open Pit Mining Soil & rock (overburden) are removed from top of ore deposit  Use explosives or heavy machinery  AKA- mountain top removal Loaders remove the exposed coal Pit is then refilled with overburden & covered with soil. Some types of ore are taken to heap leaching ponds where mineral is removed from the ore rock.  Gold miners used to use mercury to extract gold but proved very poisonous to animals & plants  Now gold is extracted from ore rock using cyanide. Cyanide is also very poisonous. Bottom picture: Open pit gold mine with heap leaching cyanide ponds down below.
    11. 11. Machine used in open pit miningBucket Wheel Excavator- cost $184,400,000Takes 5 people to operate it, moves 10 meters per minute, power lines have to be removed whenmoving it.
    12. 12. 2. Quarrying Open pit mine that is used to harvest  Granite  Marble Granite quarry in Elberton, GA  Sand  Gravel  Crushed rock (aggregates) LaFarge Granite  Clay Quarry in  Gypsum Douglasville, GA  Talc
    13. 13. 3. Solar Evaporation  Place sea water into shallow ponds  Water evaporates and leaves crystallized salt behind  30% of world’s salt produced this way  Used largely in developing countries Salt evaporation ponds in San Francisco Bay. The beautiful colors are a result of harmless bacteria and brine shrimp that live among the salt. The colors vary depending on the “age” of the pond.
    14. 14. C. What is placer mining?  Rock with minerals weathers & disintegrates  Minerals carried by water in streams  As streams bend, the water slows, minerals fall out of slower water and accumulate as placer deposits  Can also occur along coastline where waves keep minerals from moving out to sea.  Use dredging to remove minerals  Bucket system that scoops sediment with minerals from bottom of body of water.  Minerals are separated from sediment Scoop placer deposits in bucket, deposit on barge, barge takes to refinery for separation.
    15. 15. How is mineral removed from ore? Smelting  Crushed ore heated to high temps.  Impurities are trapped by a material called flux & create slag that forms a layer on top of the melted metal which is easily removed (but toxic)  Purified molten metal falls to the bottom of the furnace and is harvested. Heap Leaching  Using chemicals to dissolve mineral from ore  Ex: cyanide used to remove gold  Ex: sulfuric acid used to remove copper Copper can be extracted thru smelting (top) OR thru heap leaching (bottom).
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