1. Mining & Mineral ResourcesChapter 16, Section 2: Mineral Exploration & Mining Standards: SEV4a, b, e

2. What are the steps in harvestingminerals? Prospecting- finding placeswhere ores occur Mine exploration &development- learn whetherore can be extractedeconomically Mining- extract ore fromground Extraction- separate oreminerals from other mined rock Smelting & refining- extractpure mineral from ore mineral(get the good stuff out of wasterock) Transportation- carrymineral to market Marketing & sales- findbuyers & sell the mineral 3. How do we know where mineraldeposits are located? Airplanes can carry instruments thatdetect 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 areMiddle picture- short wavelengths usedtaken, 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 containtheir content & gradevaluable minerals. Red indicates quartz Test holes are drilled to create a 3Destimate of the extent of the ore This will tell the driller if the amountand grade of ore is high enough towarrant the cost of opening a mine.How Much Does a Mine Cost? 4. 3 Types of MiningA. Subsurface miningB. Surface miningC. Placer mining 5. A. What is subsurface mining? Mining of ore deposits 50mor more below Earthssurface. (This is as long asan Olympic size pool) 3 types of subsurfacemining:1. Room & Pillar mining2. Longwall mining3. Solution mining 6. 1. Room & Pillar Mining Coal & Salt can be mined thisway Rooms are cut into a coalseam. Coal seam is a long,wide, layer of coal. The walls of the room act aspillars to prevent collapse. After all rooms of coalremoved, the pillars are takendown starting with farthestaway. 7. 2. Longwall mining A shearer machine movesback and forth along thecoal seam. Sheared coal drops onto aconveyor belt and exits themine Hydraulic roof supportsare used to preventcollapse 8. 3. Solution Mining Potash, salt, sulfur are solublein 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. B. What is surface mining? Used when ore deposits arelocated close to Earthssurface 3 types1. Open Pit Mining2. Quarrying3. Solar Evaporation 10. 1. Open Pit Mining Soil & rock (overburden) areremoved 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 heapleaching ponds where mineral isremoved 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. 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. 2. Quarrying Open pit mine that is usedto harvest Granite MarbleGranite quarry in Elberton, GA Sand Gravel Crushed rock (aggregates)LaFarge Granite Clay Quarry in Gypsum Douglasville, GA Talc 13. 3. Solar Evaporation Place sea water intoshallow ponds Water evaporates andleaves crystallized saltbehind 30% of worlds saltproduced this way Used largely in developingcountries 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. C. What is placer mining? Rock with minerals weathers &disintegrates Minerals carried by water instreams As streams bend, the water slows,minerals fall out of slower waterand accumulate as placer deposits Can also occur along coastlinewhere waves keep minerals frommoving out to sea. Use dredging to remove minerals Bucket system that scoopssediment with minerals frombottom of body of water. Minerals are separated fromsedimentScoop placer deposits in bucket,deposit on barge, barge takes torefinery for separation. 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 copperCopper can be extracted thru smelting (top)OR thru heap leaching (bottom).