Mineral resources and exploitation

• What is the lithosphere?

  The lithosphere is the rigid outer layer of the Earth, consisting of the crust and the uppermost part of the mantle.
• Lithosphere provides resources and services

  1. Physical resources
  2. Biogeochemical cycles
  3. Soil
• What is a mineral?

  A chemical compound with a specific chemical formula.
• What is a rock?

  A mixture of minerals.
• What is an ore?

  A rock that has enough mineral deposit to be exploited commercially.
• Unsustainable exploitation of the lithospheres resources can result in:

  1. Exhaustion of reserves
  2. increased production of harmful wastes
  3. Land degradation
  4. Lower quality of life for current and future generations
• Igneous rocks - produced by solidification of molten magma
• Sedimentary rocks - produced by the deposition of sediments
• Metamorphic rock - produced by intense heat and pressure.
• Two types of Igneous rocks

  1. Intrusive rocks - magma cools and solidifies slowly below the earth's surface
  2. Extrusive rocks - lava cools and solidifies quickly on the earths surface
• Batholith is a large, intrusive igneous body that is composed of a solidified molten magma.
• Hydrothermal deposition

  1. Hot mineral solutions flow across fissures away from batholith
  2. Different minerals have different solubilities
  3. Minerals are separated by fractional crystallisation at the temperature they become insoluble.

  
• high temperatures and extreme pressure can turn limestone into marble
• Extreme pressure can turn mudstone to slate
• Granite can be turned into Gneiss
• What does lasky's principle state?

  As ore purity of a deposit decreases, there is a logarithmic increase in the amount of material that is included.
• What is meant by the term stock?

  All material that exists in the lithosphere
• What is a resource?

  All materials that can be exploited now and in the future due technological advances.
• What is a reserve?

  Proportion of a resource that can be economically exploited with existing technology.
• Ore purity - the purer the ore the cheaper it is to extract the metal from it.
• The purity of the ore can affect the area of the mine that can be economically exploited.
• What is meant by cut-off ore grade?

  The lowest purity that can be economically mined at current market prices.

  
• Increase in market value means a decrease in cut-off ore grade, and an increase in reserves.
• Increase in mining costs means an increase in cut off ore grade and a decrease in reserves.
• Improvement in mining technology means a decrease in cut-off ore grade and an increase in reserves.
• Decrease in market value would mean an increase in cut-off ore grade and a decrease in reserves.
• Satellite surveys

  1. Infrared surveys - different minerals emit different infrared radiation
  2. Gravimetry - gravimeters detect different variations in density and mass.
• Aerial surveys

  1. Magnetronomy - Magnetometers detect rocks that are more magnetic
• Surface based surveys

  1. Seismic surveys - involve sound waves produced by explosions that can echo and show depth, density and shape of a rock
  2. Resistivity - Measurement of difficulty electricity passes through the rock.
  3. Trial drilling - Most expensive technique that gives scientists a rock sample.
  4. chemical analysis - laboratory tests confirm chemical composition.
• Ore purity:

  • Lower ore purity means more rock has to be mined
• Chemical form:

  • Chemical form affects ease of extraction
• Hydrology and overburden:

  • As depth increases, more water flows in and pumping it out is expensive
  • Rock above (overburden) increases
• Shape:

  • If the reserve is concentrated, the cost of extraction will be less
  • If deposits are dispersed, it will be more expensive
• Depth:

  • Deeper the reserve, the more costly
• Economic viability:

  • Market prices needs to be high enough to economically mine.
• Transport costs:

  • Are there existing suitable transport structures
• Environmental impacts of mineral exploitation

  1. Spoil disposal
  2. Land take
  3. Traffic congestion
  4. Amenity loss
  5. Habitat loss
  6. Flooding
  7. Noise pollution
  8. Subsidence
  9. Exploration
  10. Air and water pollution