AS The Lithosphere Flashcards
Alluvial deposits
a sedimentary process which produces deposits of valuable materials formed due to being carried and separated to to flowing water, deposition depends on the density of the solids and the velocity of the water, eg gold, diamonds, tin
Bioleaching
A method of using bacteria to dissolve metals from low grade ores.
Biological sediments
a sedimentary process which produces mineral deposits formed from living organisms eg coal, limestone
Cradle to Cradle design
designing products so that materials can be reused at the end of the life of the product.
Cut-off ore grade
The lowest purity of a mineral that can be exploited economically.
Evaporites
a sedimentary process which produces valuable deposits formed from the evaporation of water leaving crystallised salts, eg sodium chloride
Gravimetry
A geological exploration technique that detects changes in the force of gravity. Used in mineral exploitation to identify dense deposits
Hydrothermal deposition
the igneous process which produces valuable deposits. Valuable metals are deposited from hot mineral-rich solutions when intrusions of magma heat ground water, minerals are deposited at different temperatures as the water moves away from the hot magma (fractional crystallisation) along veins. Eg silver, gold, lead, tin
Iron displacement
A method used to process metal ores by using a more reactive metal (iron) to reduce (remove oxygen) from the valuable metal such as copper which will the come out of solution an can be collected
Lasky’s principle
The theoretical model stating that, as the purity of available mineral deposits declines in a linear fashion, there is a logarithmic increase in the amount of the material present.
Lithosphere
The relatively hard outer layer of the Earth comprising the crust and upper layer of the mantle. It is the source of mineral resources such as metal ores and affects soil formation and properties.
Magnetometry
A method of detecting mineral deposits based on their magnetism.
Metamorphic processes
Geological processes that change the form of a rock with heat and/or pressure, but without melting it. Eg slate from shale, marble from limestone
Overburden
The soil and rock above a mineral deposit that must be removed to provide access.
Phytomining
A method used to extract metals that have been absorbed and concentrated by plants. It can be used as a method to exploit low purity metal deposits or decontaminate polluted areas.
Bioleaching
the use of living organisms to extract metals from their ores
Polymetallic nodules or manganese nodules
metal rich nodules found on the seabed approx 5-10 cm in diameter. They contain manganese, iron, nickel, copper, cobalt and titanium. Exploitation may become viable in the future if the value of these materials rises or the mining methods become cheaper.
Proterozoic marine sediments
a sedimentary process which includes the iron oxide deposits produced by the reaction of dissolved iron minerals with the oxygen produced by photosynthesis. This occurred in the early Proterozoic era and delayed the build-up of oxygen in the atmosphere.
Trial drilling
an expensive method of surveying where samples can actually be obtained and undergo chemical analysis to determine chemical composition and purity
IR spectroscopy
a survey technique which identifies different minerals by the different wavelengths that infrared is emitted from them
Reserve
the amount of the resources that can be exploited now, economically using existing technology
Resistivity
A method of predicting the mineral composition of mineral deposits underground using the ease with which they conduct electricity.
Resource
includes all of the material that could be theoretically exploited, includes the reserve and the material that could be obtained but not at profit. If value rises or extraction costs fall, some of the resource may become the reserve in the future
Secondary enrichment
a sedimentary process which produces deposits of metals that oxidise at the surface, percolate down through the ground and are precipitated below the water table when they reduce (lose oxygen) in anaerobic conditions and come out of solution
Seismic surveys
These use sound waves produced at the surface that reflect off underground geological structures to determine the depth and shape of the rock structures. The reflected sound waves are detected by geophones at the surface.
Stock
this includes all of the resource that exist in the lithosphere including the reserve, the resource and the material that we know exists but cannot ever be extracted.
What would decrease the cut off ore grade?
decreased cost of extraction, increased market value
What would increase the cut off ore grade?
increased cost of extraction, decreased market value
Impacts of mining
Habitat loss, Dust, Increased turbidity, Noise, Spoil disposal, Acid mine drainage
Barriers to recycling
Transport costs, labour costs, difficulty identifying and separating materials, public cooperation
Factors affecting mine viability
Ore purity, Overburden, Hydrology (eg above or below the water table), Depth, Transport costs, Labour costs, Energy costs, Market demand and value
