Mineral resources Flashcards
Define mineral
- a solid, naturally occurring inorganic substance with a definite chemical structure
Define resource
- a source of supply or support
What is a sedimentary rock
- a rock that has formed through the deposition and solidification of sediment, limestone and chalk
What is a metamorphic rock
- started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary or earlier metamorphic form
What is an igneous rock
- types of rocks that are formed when molten rock cools to a solid state
Proterozoic marine
- iron ions were present in oceans in solution
- iron ions react with O2 to form iron oxides
- iron oxides form deposits on ocean floors
Describe how alluvial deposits can separate and concentrate valuable metals and minerals
- rivers with high energy and velocity carry lots of sediment
- as energy and velocity decrease, sediments drop out of suspension and are deposited
Explain the process of secondary enrichment
- metal ores are exposed at the surface
- exposed to oxygen and water
- metal oxidises and goes into solution
- water perculates downwards until it reaches the water table
- metal reduces
- metal precipitates
- copper is concentrated just below the water table
Explain how evaporites form
- sea levels decrease
- temporary lakes may also form
- water contains salts
- water evaporates
- salt precipitates and deposits on land
Explain how biological deposits can form sedimentary rocks
- they are remains of living organisms
- over time, remains lithify
- e.g coal - formed from terrestrial vegetation
Explain how granite batholiths are formed
- large volume of magma that moves up through the earth’s crust, but doesn’t reach the surface
- cools and solidifies in the crust to form granite
- associated with tectonic plate movement
Explain how hydrothermal metal ores are deposited
- via hydrothermal deposition
- hot magma rises through lithosphere
- water in surrounding rocks become superheated
- metals and minerals go into solution
- how water moves away from magma along fractures
- water cools
- metals and minerals precipitate out of solution at different temperatures
Explain how slate is formed
- formed from shale
- undergoes heat and pressure
- becomes slate by changing
Explain how marble is formed
- formed from limestone
- undergoes heat and pressure
- becomes marble by changing
Define reserve
- the amount of the resource that is economically viable and can be exploited with today’s existing technology and prices
Define stock
- all of the material on the lithosphere that exists
How might a reserve increase
- develop new technology
- increase value
- cost of labour decrease
How might reserves decrease
- problems with equipment supple
- increase labour, equipment and energy cost
- decrease value
What is lasky’s principle
- as purity of a mineral decreases the amount of the mineral increases exponentially
Define cut off ore grade
- the grade of material that has been set by a mining company as the minimum grade that can be extracted to make a profit
Why might the cut off ore grade change over time or from place to place
- deeper deposits - harder to extract
- decrease value - increase cut off grade
- increase value - decrease cut off ore grade