Last minute geology

Rock examples
1. Igneous
  1. Intrusive- granite, quartz
  2. Extrusive- Pumice, basalt
2. Sedimentary
  1. conglomerate
  2. sandstone
  3. mudstone
3. Metamorphic
  1. limestone=marble
  2. siltstone=slate
Exploration methods
1. The search for the rocks containing the minerals, oil or coal
2. Aerial methods
  1. Magnetic surveys
    1. Iron, nickel, cobalt change magnetic field
    2. Magnetometers- detect change
    3. 'magnetic anomaly'
  2. Gravity surveys
    1. Gravimeters- detect changes in gravitational pull
    2. Dense r&m affect pull
  3. Electromagnetic surveys
    1. detects good electric conductors
    2. Magnetic field sent from transmitter(plane)
      1. MF makes tiny eddy currents in minerals
        Eddies make own magnetic field(secondary field)
        Receiver detects SF
    3. copper sulfide, lead sulfide, zinc sulfide, gold, silver
3. On-site methods
  1. Seismic survey
    1. Shock wave into ground
    2. record reflecting sound waves
    3. geophones, detect sound waves
    4. structure of Earth's crust 35-60km deep
      1. help understand how minerals form
    5. help predict where minerals are
  2. Geochemical surveys
    1. Geochemistry
    2. samples from surface/drill holes in rock- see amount of mineral
    3. core sample- rock removed
    4. water above/below indicator of minerals
      1. groundwater dissolves minerals
        detects diamonds, gold, uranium, copper
4. Satellite images
  1. make images using light rays we can't see
  2. sensors detect radiation- near-infrared, shortwave-infrared, thermal-infrared
  3. help see features images with normal light don't show
5. Geological maps
  1. show ore bodies from above&side
  2. side view- 'cross-section'
  3. help us decide how to best mine the ore
Mining
1. type of mineral geology of the area cost & mineral value
2. Surface Mining
  1. cheapest if near surface
  2. open-cut mine/ large pit
  3. ore removed by machines with large shovels, giant drills called augers and drag lines
3. Underground mining
  1. ore is deep, fairly concentrated, small space/narrow veins
  2. Vertical shafts
    1. horizontal shaft into ore
      1. hoist lifts it to surface
  3. Steady slope/decline
    1. ore driven out by vehicle
    2. 15 degrees
  4. inside mountain- adit- horizontal tunnels
4. Dredging
  1. minerals heavier than sand
  2. dig pit- fill with water= lake
    1. boat sucks up sand using hoses
      1. separated then sand & water piped back in
5. Leach mining
  1. minerals dissolved in fluid injected
  2. holes drilled into rock
    1. 'leach solution' is pumped into the ore
      1. dissolved ore solution pumped to the surface
  3. solution which will dissolve the ore= 'leach solution'
6. Petroleum wells
  1. Petroleum- liquide & gas- trapped within sedimentary rock layers
  2. bore narrow holes into rock
  3. Derrick- steel tower to support drilling equipment
  4. hole drilled until oil/gas found or give up
  5. clay, chemicals, water pumped through drill pipe- keep cool
  6. When found
    1. drill & pipe removed
    2. metal casing (hollow tube lowered into hole and cemented in place
    3. System of pipes and valves -'wellhead'- separates into storage tanks
    4. pumps, water/steam/gas injected to increase pressure/oil flow
  7. Rigs
    1. rest on seafloor, float wires attached, boats
    2. pumped through pipelines on seafloor to factories
    3. floating ships link to well, onboard treatment/storage
    4. flammable- disaster risk high

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	Created by emjaza almost 11 years ago