Topic 1: Rocks and Minerals

• How are igneous rocks formed?

  2 types/ examples

  From the solidification of lava

  INTRUSIVE: when magma cools and crystallises slowly within the Earth’s crust (granite).

  EXTRUSIVE: when lava solidifies on the Earth’s surface (basalt).
• How is sedimentary rocks formed?


  Rocks formed by the compression and consolidation of layers of mud, sand, silt and living organisms such as chalk, limestone and clay.
• Use of rocks and minerals:

  • Source of soils for agriculture
  • Building materials
  • Provide industrial metals and fuels
  • Precious stones for jewelry
• The rock cycle:

  • Rocks are constantly changed and recycled through weathering
  • Physical, chemical, and biological forces break down rocks into sediments
  • Sediments are transported by erosion and can form new sedimentary rocks
  • Heat and pressure can turn rocks into metamorphic rocks or melt them into magma
  • Magma can solidify to form new igneous rocks
• Extraction of rocks and minerals:

  • Two main methods: surface mining and subsurface mining
  • Surface mining: removes overburden to access ore body, uses heavy machinery
  • Subsurface mining: removes minerals through underground methods like declines, shafts, and adits
• Types of mining:

  • Surface (Open pit mining): easier access, large areas of land damaged, produces waste rock
  • Surface (Strip mining): easy access to minerals, impacts large areas of land, produces waste rock
  • Subsurface (Drift mining): access to seams from sloping tunnels, technically complex
• Factors affecting extraction:

  • Opencast/open-pit mining
  • Deep mining/shaft mining
  • Exploration
  • Geology
  • Accessibility
  • Environmental impact assessment
  • Supply and demand
• Impact of rock and mineral extraction:

  • Environmental, economic, and social impacts
  • Loss of habitat
  • Pollution (noise, water, land, air, visual)
  • Waste management
  • Employment opportunities
  • Economic improvements
  • Infrastructure development
• Managing the impact:

  • Strategies for restoring landscapes
  • Safe disposal of mining waste
  • Land restoration techniques
  • Creating lakes and nature reserves
  • Using sites as landfill
• Sustainable use of rocks and minerals:

  • Sustainable resource and development
  • Strategies for sustainable use
  • Increased efficiency in extraction and use
  • Recycling rocks and minerals
  • Legislation
• Adits provide access to seams from sloping tunnels, which is less costly than making shafts
• Majority of overburden is left in place in adits
• Sub-surface mining methods include shaft mining, which reaches minerals not accessible by other methods
• Shaft mining has less impact on the surface ecosystem but still produces waste heaps
• Shaft mining is the most expensive method and carries risks such as tunnel/shaft collapse, poisonous gases, underground fires, and explosions
• Surveying techniques are used to determine the geology of underlying rock in mineral exploration
• Factors affecting mining of rocks and minerals include expenses, geology, climate, environmental impact, supply and demand, and location suitability
• Economic impacts of rock and mineral extraction include the multiplier effect and trickledown effect
• In mineral 'greenfield' exploration, surveying techniques like detecting radiation, measuring magnetism, and remote sensing are commonly used to identify mineral deposits
• Environmental impacts of rock and mineral extraction include habitat and biodiversity loss, Pollution-air,noise,visual,water- and soil erosion and sedimentation
• Methods to manage the impact of rock and mineral extraction:

  remediation

  tailing ponds for mineral waste restoration reclamation/reuse
• How are metamorphic rock formed?

  The Earth’s movements can cause existing igneous and sedimentary rocks to be heated up and put under great pressure. 

  This can cause a chemical change in their minerals and the formation of new metamorphosed rocks (slate from shale / marble from limestone).