The Litosphere

Question 1

What are igneous processes?

Answer 1

Rocks and minerals are created by the cooling and hardening of magma or molten lava

Question 2

What is hydrothermal deposition?

Answer 2

Igneous instructions are rocks formed from magma a that cools and solidifies within the earths crust
- producing superheated pressurised water at high temperatures that dissolved minerals from surrounding rocks
- these rich solutions travel along fissures away from the igneous batholith, cooling as they do
- they cool in over of their solubility, least soluble crystallising first = fractional crystallisation
E.g. tin, copper, lead, silver, gold

Question 3

What are metamorphic processes?

Answer 3

Tectonic movements of crustal plates can alter existing ricks with high temperatures and pressure, without melting them produce metamorphic rocks
E.g. limestone to marble and mudstone to slate

Question 4

What are sedimentary processes?

Answer 4

Cause minerals to settle and build up to produce layers of deposited sediment, this deposition and subsequent cementing at the earths surface and within bodies of water creates sedimentary rocks and minerals

Question 5

What are Proterozoic marine sediments?

Answer 5

Iron ore deposited such as hematite and magnetite
- formed when dissolved iron compounds became oxidised by the oxygen released by photosynthesis, producing insoluble iron oxide deposits
- occurred 2.5-1.8 billion years ago

Question 6

What are alluvial deposits?

Answer 6

Minerals that were carried and separated by flowing water
- order of deposition is density dependent = most dense first
- order of deposition by particle size

Question 7

What are evaporites?

Answer 7

If a bay of an ancient sea became isolate, then the water may have evaporated leaving crystallised minerals such as sodium chloride behind

Question 8

What is secondary enrichment?

Answer 8

Minerals dissolve in rainwater and as they are moved and deposited their oxidation states can change

Question 9

What are biological sediments?

Answer 9

Where living organisms form mineral deposits, these processes often concentrate minerals that can be deposited in sedimentary rocks
E.g. shells of marine organism = limestone and chalk, terrestrial vegetation = coal, marine organisms = crude oil and gas

Question 10

What is Lasky’s principle?

Answer 10

In general as the purity of a mineral decreases the amount of the mineral present increases exponentially
- the actual problem is not the quantity of minerals that exists but the technology to mine lower quality ore

Question 12

What is stock?

Answer 12

All the material that exists in the lithosphere, including the mineral that can be exploited now, all the minerals which will be exploitable if prices rise or new technology is developed and could be extracted in the future, and all minerals that will never be exploited.

Question 13

What is resource?

Answer 13

Resource is larger then the reserves as it includes all the materials that is theoretically exploitable, includes all resources that are currently extractable and those that could be extracted in the future

Question 14

What is reserve?

Answer 14

The amount of the resource that can be exploited now, economically using existing technology
- if market price increases, or new technology is available then the reserve will increase.

Question 15

What are inferred reserves?

Answer 15

Presence of a mineral can be predicted from knowledge or the geological structures but not enough is known to know the exact amount that can be economically extracted

Question 16

What is a probable reserve?

Answer 16

Sufficient information about the deposit is known, amount that is economically extractable is estimated with decent accuracy

Question 17

What is a proven reserve?

Answer 17

Sufficient exploration has been carried out, including trial drilling to accurately estimate the amount of the mineral that can be economically extracted

Question 18

What is IR spectroscopy?

Answer 18

Different materials emit infrared radiation at different wavelengths and these can be used to identify them

Question 19

What is gravimetry?

Answer 19

Gravimeters detect variations in gravity caused by variations in density and mass
E.g. igneous rock = more dense than sedimentary

Question 20

What is magnetometry?

Answer 20

Detect rocks that are more magnetic such as iron ore magnetite and ores of tungsten and colbalt

Question 21

What are seismic surveys?

Answer 21

Involve sound waves produced by controlled explosions, or a seismic vibrator on the surface, echos can give information about the depth, density and shape of the rock strata

Question 22

What is resistivity?

Answer 22

Measurement of the difficulty with which electricity passes through a material
E.g. sedimentary rocks have lower resistiveness than igneous rocks due to higher water content

Question 23

What is trial drilling?

Answer 23

Most expensive technique per sampling site but it is the only method that actually produces samples of the rocks underground

Question 24

What is chemical analysis?

Answer 24

Lab tests confirm the chemical compositions and purity if the minerals in the rock

Question 25

How does ore purity affect mining viability?

Answer 25

If ore grade is low then:
- more rock has to be mined
- more waste materials will be produced
- more energy will be needed for mining and processing
- more pollution generated

Question 26

How does chemical form affect mining viability?

Answer 26

Affects the ease of the chemical extraction of the metal E.g. Al can be extracted from bauxite but not from clay

Question 27

How does overburden and hydrology affect mining viability?

Answer 27

Overburden = rock that lies above a mineral deposit - hard overburden may need blasting = expensive - loose overburden may cause landslides Higher precipitation or impermeable rocks below may increase drainage costs

Question 28

How does depth affect mining viability?

Answer 28

Costs rise rapidly as the depth increases - if the depth is doubled then the cost much more than doubles - sides of mines cannot be vertical due to landslides - as depth increases, the amount of water that flows into the mine from surface runoff or groundwater also rises, increasing pumping costs significantly

Question 29

How does cut-off ore grade affect mining viability?

Answer 29

The lowest ore purity that can be mined economically using existing technology = COG Higher market value = COOG decreases Lower market value = COOG increases Improved technology = COOG decreases Higher energy costs = COOG increases

Question 30

How does transport costs affect mining viability?

Answer 30

Ease of bulk transport, the presence of a suitable existing transport infrastructure and whether the bulk of the mineral has been reduced by processing. Affected by distance to market

Question 31

How can market economics affect mining viability?

Answer 31

Market price is controlled by the demand for the mineral, how much is produced and the costs of extraction and processing When demand and supply do not match prices can fluctuate widely

Question 32

How is land take an environmental impact of mineral exploitation?

Answer 32

Mineral extraction may cause conflicts with other land users

Question 33

How is habitat loss an environmental impact of mineral exploitation?

Answer 33

- loss of species where the mineral Is to be extracted is unavoidable as the surface habitat must be removed - removing wildlife and plants and rehoming them has proved to be unsuccessful in many cases - restoration after mining may be a requirement in some countries e.g. UK

Question 34

How is loss of amenity an environmental impact of mineral exploitation?

Answer 34

Mining changes the landscape and can create aesthetic problems - reduced by landscaping and tree planting

Question 35

How is dust an environmental impact of mineral exploitation?

Answer 35

Blasting and vehicle moments creates dust which is lifted into the atmosphere - water sprays can be sued to limit the dust by making dust particle heavier so they settle and clump together

Question 36

How is noise an environmental impact of mineral exploitation?

Answer 36

Mine vehicles and rock blasting are the two main sources of noise - embankments and baffle mounds can be built to absorb and deflect noise - disturbance limited by blasting at set times of the day so the noise is predictable and during the day

Question 37

How is turbid drainage water an environmental impact of mineral exploitation?

Answer 37

Suspended solid particles in mine drainage water can reduce light penetration into rivers and lakes and can cover and kill plants and animals - sedimentation lagoons can help where the sediment settles and the low turbid water is drained

Question 38

How is spoil disposal an environmental impact of mineral exploitation?

Answer 38

Solid waste material left behind by mining, overburden and unwanted material and can cause may problems: - aesthetics = spoil heaps damage scenic beauty, landscaping can help - stability = lack of compaction = landslides e.g. Aberfan school in 1966, can be prevented will slopped mining, plating trees - leachate = rainwater percolating through spoil can dissolve toxic metals and sulfides that produce acidic leachate = pass through a filter bed of crushed limestone to immobilise the metal

Question 39

What is mine site restoration?

Answer 39

New uses may be found for sites that have been used for mining E.g. sand, gravel and clay pits are flooded and developed as wetland wildlife reserves

Question 40

How can better remote sensing image resolution increase further mineral supplies?

Answer 40

Newer satellites may carry out improved sensors which generate greater numbers of image pixels Multispectral sensors detect a greater range of wavelength of visible and IR light, providing more detailed information of mineral composition

Question 41

How can portable field equipment increase future mineral supplies?

Answer 41

Lab equipment becoming smaller and more portable as electronic components have become lighter, more powerful batteries developed and energy consumption reduced - saves time and results are available immediately

Question 42

How is improvements in mechanisation increasing future mineral supplies?

Answer 42

Deep mining = machines allows mining where it may be too hot or dangerous for people;e Open-cast mining = larger machinery in open-cast mines allows overburden and minerals to be extracted more quickly and cost-effectively

Question 43

How can low grade deposits be exploited by bioleaching?

Answer 43

Use if living organisms to extract metals from their ores: - Acidophilic bacteria can be used to extract metals such as copper, zinc and gold form low grade sources, the bacteria oxides sulfide ores and produce sulfuric acid which dissolves the metals - metals in solution can be separated by electrolysis or by using carbon filters

Question 44

How can low grade deposits be extracted using phytomining?

Answer 44

Some plants absorb metal ions from, soil or water and concentrate them in their leaves, this can be used as a method of decontaminating polluted sites and as a method or commercial extraction of metals - vegetation is harvested and metals are collected from the ashes with acid and then electrolysis

Question 45

How can low grade ore deposits be extracted using iron displacement?

Answer 45

Iron is a more reactive metal then copper and will displace copper ions from solution, solid iron goes into solution as the coper ions are deposited as solid copper metal which can be collected

Question 46

How can low grade deposits be extracted using leachate collection?

Answer 46

Rainwater percolating through spoil heaps dissolves soluble metal ions - draining the leachate can be recirculated through the spoil to increase the concentration of metal ions in solution - when the concentration is high enough the metals can be extracted by electrolysis

Question 47

How can low grade deposits be extracted by rare earth metals?

Answer 47

Used in small amounts in many important applications: leaching, solvent extraction, and separation techniques to produce a mixture of rare earth salts, followed by purification and metal production

Question 48

How can low grade deposits be extracted by polymer adsorption?

Answer 48

Metal ions dissolved in seawater will adsorb onto the surface of some polymers and can be collected later

Question 49

What are poly metallic nodules?

Answer 49

Metal-rich nodules found on the seabed of many of the earths oceans - may have been formed by chemical precipitation of metals around a small solid object such sad the shell of a marine organism - large scale exploitation is expensive and previously inaccessible

Question 50

What are the environmental impacts of polymetallic nodules?

Answer 50

- recovering nodules will disturb the seabed and kill benthic species - separating nodules from the seabed will increase turbidity of the water - re-deposition of the sediments is likely to kill filter feeders also covering and killing benthic organisms

Question 51

What is pre-consumer waste?

Answer 51

The waste trimmings produced by cutting or stamping machines

Question 52

What is post-consumer waste?

Answer 52

Discarded consumer products - most waste can be recycled if separated,

Question 53

What are the problems with recycling schemes?

Answer 53

- transport = expensive and bulk transport is not always available - labour costs = processing smaller quantities increases labour costs - separation = alloys not easily separated - identification = labour intensive to work out the composition - energy costs - public cooperation - waste losses = not all materials can be recycled

Question 54

What is cradle to cradle design?

Answer 54

If the lifetime of the minerals in used can be extended then the need to exploit reserves will be reduced Cradle - cradle design involves the design of products so that the materials used are able to be reused and identified