1. Rocks, Minerals, Mining

2. Rocks and the Rock Cycle
The rock cycle is the constant formation and destruction of rock The rock cycle recycles scarce minerals and elements

3. Rocks
Rocks are any solid mass of mineral or mineral-like matter occurring naturally as part of our planet
Types of Rocks
Igneous rock is formed by the crystallization of molten magma
Intrusive form within the earth
Extrusive form when magma cools above the earth’s surface

4. Rocks
Types of Rocks
Sedimentary rock is formed from the weathered products of preexisting rocks that have been transported, deposited, compacted, and cemented.
Metamorphic rock is formed by the alteration of pre-existing rock deep within Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids.

5. Rock Cycle

6. Rock Cycle Energy That Drives the Rock Cycle
Processes driven by heat from the Earth’s interior are responsible for forming both igneous rock and metamorphic rock
Weathering and the movement of weathered materials are external processes powered by energy from the sun.
External processes produce sedimentary rocks

11. Minerals Definition of a Mineral Naturally occurring Solid substance
Orderly crystalline structure
Definite chemical composition
Generally considered inorganic

12. Minerals How Minerals Form Crystallization from magma Precipitation
Pressure and temperature
Hydrothermal solutions

17. Weathering & erosion

18. Physical Weathering The mechanical breakdown of rocks and minerals
Can be caused by:
Water, wind, temperature variations
Biological agents such as roots
Bottom line: more surface area for chemical weathering

19. Chemical Weathering
Breakdown caused by chemical rxns, and/or dissolving of elements from rocks
Can be caused by:
Naturally occurring acids
Lichens produce acid to break down rock
Anthropogenic: acid rain

20. Erosion The physical removal of rock fragments (sediment, soil, etc)
A result of 2 mechanisms:
Physical: wind, water, ice
Biological; burrowing animals
Erosion is a natural process

21. Distribution of mineral resources

23. Surface Mining Strip mining:
Removal of “strips” of soil and rock to expose ore
Large volume of material is removed, resource extracted and the tailings are returned

25. Surface Mining Open-pit mining:
Creation of a large pit; resource close to sfc, but extends
Copper mines
Mountaintop removal
Uses explosives to remove the entire top of a mountain
Tailings are often deposited in lower elevations (rivers and streams)

28. Surface Mining Placer Mining
Process of looking for minerals in river sediments
California gold rush

29. Subsurface Mining If mineral resource is more than 100m below sfc
Begins with horizontal tunnel
Vertical shafts are drilled
Deepest mines on earth – 3.5 km

30. Mining Safety and the Environment
Soil erosion
Waterway damage
Habitat fragmentation
Pollution from tailings
Groundwater & stream damage (mountaintop)
Placer mining uses toxic metals (Hg)
Acid mine drainage (pumped out of tunnels)

31. Mining Safety and the Environment
Subsurface mining is dangerous
Explosions
Accidental burial
Fires
Respiratory diseases (e.g. black lung disease)

32. Mining Legislation Mining Law of 1872
Regulate mining of Ag, Cu, Au ores and fuels on federal lands
Written to encourage development and settlement of west
Surface Mining Control & Reclamation Act of 1977
Mandate: minimal disturbance of land during mining and reclaimed after