The Physical Environment (AS); The Lithosphere (Complete)

Question 1

What is the lithosphere made up of and what does it include?

Answer 1

-Made up of solid crust & upper mantle
-Includes rocks, mineral resources & soils providing environmental resources & services important for human societies

Question 2

Mineral resources; what are the major uses and global annual production/t of the metals- iron, aluminium and copper?

Answer 2

Iron- 1700m, major uses; buildings (girders, steel reinforced concrete), transport (ships, road vehicles) & appliance cases (cookers, fridges)
Aluminium- 53m, major uses; packaging foils, vehicles, widow frames
Copper- 19m, major uses; electric cables, water pipes

Question 3

Mineral resources; what are the major uses and global annual production/t of the metals- zinc, lead and titanium?

Answer 3

Zinc- 14m, major uses; steel protection (galvanising), batteries, alloys (brass)
Lead- 9m, major uses; lead-acid batteries, construction (roof/window flashing), radiation shielding
Titanium- 6m, major uses; white pigments in paint/plastic/paper, aircraft & spacecraft (as aluminium alloys)

Question 4

Mineral resources; what are the major uses and global annual production/t of the metals- nickel, tin and uranium?

Answer 4

Nickel- 2.1m, major uses; metal alloys to increase tensile strength, eg jet engine turbines
Tin- 360,000, major uses; solder, rust prevention in tin plated steel food cans, glass manufacturer
Uranium- 66,000, major uses; nuclear fuel for power stations

Question 5

Mineral resources; what are the major uses and global annual production/t of the metals- cadmium, lanthanum and neodymium?

Answer 5

Cadmium- 25,000, major uses; rechargeable batteries
Lanthanum- 25,000, major uses; batteries for hybrid vehicles, sponge-alloy hydrogen store
Neodymium- 25,000, major uses; magnets (electric motors, lasers)

Question 6

Mineral resources; what are the major uses and global annual production/t of the metals- cerium, yttrium and gold?

Answer 6

Cerium- 50,000, major uses; catalytic converters, diesels additives to increase combustion efficiency, LCD screens
Yttrium- 10,000, major uses; LED lights
Gold- 2500, major uses; coins, jewellery, electrical conductors

Question 7

Mineral resources; what are the major uses and global annual production/t of the metals- mercury, indium, gallium and platinum?

Answer 7

Mercury- 2000, major uses; fluorescent lamps, thermometers
Indium- 710, major uses; electronics (transistors, semiconductors)
Gallium- 440, major uses; electronics (LED lights, photovoltaic solar panels)
Platinum- 220, major uses; vehicle catalytic converters, catalyst in chemical industry

Question 8

Mineral resources- what are the major uses and global annual production/t of the industrial minerals/construction minerals- aggregates, limestone and sodium chloride?

Answer 8

Aggregates (sand,gravel)- 40b, major uses; concrete, building mortar, glass
Limestone- 600m, major uses; cement, crushed for road surfacing & rail-track ballast, building blocks
Salt (sodium chloride)- 290m, major uses; source of chlorine for manufacture of paper, plastics, water sterilisation. De-icing roads, food additive.

Question 9

Mineral resources- what are the major uses and global annual production/t of the industrial minerals/construction minerals- gypsum, sulfur and kaolin?

Answer 9

Gypsum (china clay)- 180m, major uses; building plaster, food additive
Sulfur- 75m, major uses; sulfuric acid manufacture to make phosphate fertilisers, pest control
Kaolin (from china clay)- 26m, major uses; filler & coating for paper, ceramics (porcelain), filler (paint, cosmetics, toothpaste)

Question 10

What are the metals used in the different mobile phone components?

Answer 10

-Case; magnesium, titanium, chromium
-Electronics; aluminium, antimony, gallium, mercury,zirconium, silver, platinum
-Battery; manganese, cobalt, nickel, cadmium, terbium, dysprosium, erbium, thulium, ytterbium, lutetium
-Speaker & vibration unit; iron, tungsten, neodymium
-Screen; silicon, cerium, indium

Question 11

What are igneous processes and what can they produce?

Answer 11

-Processes by which rocks and minerals are created by cooling and hardening of magma or molten lava
-They can produce exploitable mineral deposits

Question 12

Hydrothermal deposition: what is the process of fractional crystallisation?

Answer 12

-Igneous intrusions - rocks formed from magma that cools & solidifies within Earth’s crust.
-They produce pressurised superheated water at high temps that dissolves many minerals from surrounding rocks.
-These mineral-rich solutions travel along fissures away from igneous batholith, cooling as they do so dissolved minerals crystallise and come out of solution.
-They do this in order of their solubility: least soluble crystallising first.

Question 13

Hydrothermal deposition: how does exploitation become possible for minerals that can’t be?

Answer 13

-Process of fractional crystallisation starts w/ mixture of minerals that couldn’t have been exploited.
-Once minerals become separated & deposited, soon after batholith formed, later exploitation became possible.

Question 14

What are the metal ores deposited by hydrothermal processes?

Answer 14

Tin, copper, lead, silver, gold and arsenic.

Question 15

How do metamorphic processes create exploitable mineral deposits?

Answer 15

-Igneous processes & tectonic movements of crustal plates can alter existing rocks w/ high temps & pressure, w/out melting them producing metamorphic rocks.
-High temps & extreme pressure can change limestone → marble.
-Extreme pressure can change mudstone → slate

Question 16

How do sedimentary processes create exploitable mineral deposits?

Answer 16

-Cause minerals to settle & build up to produce layers of deposited sediment.
-The deposition & subsequent concentration at Earth’s surface & within bodies of water → creates sedimentary rocks & minerals.

Question 17

How do Proterozoic marine sediments create exploitable mineral deposits?

Answer 17

-Include iron ore deposits, eg haematite & magnetite
-Formed when dissolved iron compounds became oxidised by oxygen released by photosynthesis; making iron oxide deposits.
-Occurred mainly between 2.5 and 1.8 billion years ago

Question 18

How do alluvial deposits create exploitable mineral deposits?

Answer 18

-Involve materials that were carried & separated by flowing water.
-ability of water to carry solids depends upon velocity of water & density of solids
-materials exploited from alluvial deposits include gold, diamonds, tin, ore, gravel, sand, clay

Question 19

How do evaporites create exploitable mineral deposits?

Answer 19

-lf bay of ancient sea became isolated, water may have evaporated leaving crystallised minerals, eg halite (sodium chloride)
-evaporites also form in inland seas in desert areas as water from inflowing river evaporates

Question 20

How does secondary enrichment create exploitable mineral deposits?

Answer 20

-Many economically important metals can form minerals soluble/ insoluble depending on conditions, esp availability of oxygen.
-May be transported in solution, by moving water & then deposited as their oxidation state changes.

Question 21

How do biological sediments create exploitable mineral deposits? + examples

Answer 21

-Processes where living organisms form mineral deposits.
-Often concentrate minerals that can be deposited in sedimentary rocks

-shells of marine organisms; produce limestone & chalk
-terrestrial vegetation; produce coal
-marine organisms; produce crude oil & natural gas

Question 22

Why does the rate of mineral exploitation not match the quantity of exploitable deposits existing?

Answer 22

-# of exploitable deposits existing in the crust of every mineral = much greater than we could realistically use
-Most deposits are in inaccessible places, or at purities too low for current economic exploitation

Question 23

What does Lasky’s principle state and what does it involve?

Answer 23

-States that: in general, as the purity of a mineral decreases, the # of mineral present ↑ exponentially.
-so → major problem w/ future mineral supplies isn’t quantity that exists but need to develop methods to exploit low-grade deposits
-to help w/ estimates of future availability it’s important to predict which deposits are likely to become exploitable in future + when
-involves many estimates & uncertainties

Question 24

What can mineral deposits in the crust be categorised by?

Answer 24

According to whether the technology exists to exploit them and whether this exploitation would be economically viable

Question 25

Why is mineral exploitation a long/difficult process?

Answer 25

-Takes a long time to prepare a mine before any of the mineral can actually be extracted
-Preparation includes gaining detailed info on mineral to be mined
-The methods providing this info are expensive, esp trial drilling
-So deposits not exploited in near future = may be investigated w/ cheaper methods providing less detailed info.
-More thorough exploratory investigations would be carried out nearer time exploitation may take place

Question 26

What does stock (also called resource base) include?

Answer 26

-Includes all material existing in lithosphere
-Includes mineral that can be exploited now, which will be exploitable when prices ↑/ new technologies develop, that which will never be technologically/economically exploitable

Question 27

What does resource include?

Answer 27

-Larger than reserve as includes all material theoretically available for exploitation; includes deposits (the reserves) plus those that can’t be exploited now, but w/ realistic increases in price/new technologies could be extracted in future
-Resources that are deep, low grade, in a difficult chem form, or in locations currently protected, could all become usable in future

Question 28

What do reserves include?

Answer 28

-Amount of resource that can be exploited now, economically, using existing technology
-While size of resource= finite, quantity counted in reserve can change
-Eg if market price for resource increases/new extraction technologies become economically viable—> reserves will increase. If market prices fall, reserves may decrease

Question 29

What are the different categories of mineral reserves and their descriptions?

Answer 29

-Inferred reserves; presence of mineral that can be predicted from knowledge of geological structures present, not enough known to estimate amount that can be economically extracted

-Probable reserves; sufficient info about deposit known, so # of mineral that can be economically extracted can be estimated w/ sufficient accuracy that further exploitation—> justified

-Proven reserves; sufficient exploration carried out, incl trial drilling, to accurately estimate # of mineral that can be economically extracted

Question 30

What are some factors that limit the viability of exploitation?

Answer 30

-Absence of technology to exploit deposits
-Financial cost of exploitation may be too great
-Environmental impact of exploitation may be unacceptable

Question 31

What is remote sensing and when can it be done?

Answer 31

-Involves any technique giving info w/out taking direct samples
-Can be done at different distances from deposits, collecting data on range of scales: satellite/aircraft/ground-based surveys

Question 32

Are large scale surveys cost effective and why?

Answer 32

-Can be more expensive but often v cost effective
-Provide lots of info at relatively low cost per unit surveyed area

Question 33

Survey techniques; what is IR spectroscopy?

Answer 33

Different minerals emit IR at different wavelengths, these can be used to identify them

Question 34

Survey techniques; what is gravimetry?

Answer 34

-Gravimeters detect variations in gravity due to variations in density & mass
-Igneous rocks= often more dense than sedimentary deposits

Question 35

Survey techniques; what is magnetometry?

Answer 35

Magnetometers detect rocks more magnetic, eg iron ore magnetite & ores of tungsten & cobalt

Question 36

Survey techniques; what are seismic surveys?

Answer 36

-Involve sound waves produced by controlled explosions/seismic vibrator on surface
-Echoes can give info about depth, density & shape of rock strata

Question 37

Survey techniques; what is resistivity?

Answer 37

-Measurement of difficulty w/ which electricity passes through material
-In general, sedimentary rocks have lower resistivities than igneous rocks bc; have higher water contents

Question 38

Survey techniques; what is trial drilling?

Answer 38

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

Question 39

Survey techniques; what is chemical analysis?

Answer 39

Laboratory tests confirm chemical composition & purity of minerals in rock samples

Question 40

How does ore purity affect mining viability?

Answer 40

-Affects financial costs of exploitation & environmental impacts of mining
-If ore grade= low; more rock needs to be mined, more waste materials (spoil) made, more energy needed for mining & processing, more pollution generated

Question 41

How does chemical form affect mining viability?

Answer 41

-Affects ease of chemical extraction of metal
-Eg, aluminium can be extracted from bauxite (aluminium oxide) but not from clay (alumino-silicates); more abundant

Question 42

How does overburden and hydrology affect mining viability?

Answer 42

-Overburden= rock lying above mineral deposit. Loose overburden may increase landslide risk, so sides of mine void may have to be landscaped at more gentle gradient;
-May increase overall area of mine
-Higher precipitation/impermeable rocks below may increase drainage costs

Question 43

How does depth affect mining viability?

Answer 43

-Costs rise rapidly as depth increases
-If depth= x2, cost much more than x2
-Sides of mine cant be vertical bc risk of collapse, so # of rock needing to be removed to reach mineral rises rapidly as depth increases
-As depth increases, # of water flowing into mine from surface runoff/groundwater also rises, increasing pumping costs significantly

Question 44

How does cut-off ore grade (COOG) affect mining viability?

Answer 44

Mining → has to be economically profitable = must be balance between production costs & income
Lowest ore purity that can be mined economically w/ existing technology = cut-off ore grade (COOG), this changes as technology improves & market prices fluctuate
Mineral reserves include deposits above COOG

Question 45

How do changes in market value and technology impact the COOG?

Answer 45

Higher market value; COOG decreases
Lower market value; COOG increases
Improved extraction technology; COOG decreases
Higher energy costs; COOG increases

Question 46

How do transport costs affect mining viability?

Answer 46

These are affected by distance to market, ease of bulk transport, presence of suitable existing transport infrastructure & whether the bulk of mineral has been reduced by processing

Question 47

How do market economics affect mining viability?

Answer 47

-Market demand & sale value of minerals control economic viability of exploiting specific mineral deposit
-Market price → controlled by demand for mineral, how much is produced & costs of extraction & processing
-lamount that can be supplied increases relatively slowly as mines = developed but demand can ↑ and ↓ quickly
-When demand & supply don’t match prices can fluctuate widely. Uncertainty makes production of future markets very important
-exploiting deposits in regions w/ existing mining activities produces benefits by having access to existing infrastructure for transport & energy, equipment supplies & trained workforce.

Question 48

How does mineral exploitation impact land take?

Answer 48

-Can cause conflicts w/ other local land uses
-Minerals can only be exploited where they were deposited; makes land conflicts more likely as there’s limited location choice
-Land area required to access mineral= larger than area of mine void (hole) itself
-Land is required for associated buildings, access routes, overburden/spoil dumping & possibly buffer zone between mine & neighbouring area
-Open cast mining—> more habitat loss than deep mining

Question 49

How does mineral exploitation cause habitat loss and how can this be counteracted?

Answer 49

-Loss of species where mineral is extracted= unavoidable as surface habitat needs to be removed
-Removing wildlife by capturing animals & transplanting plants to move them to unthreatened habitats—> attempted but rarely successful. Some species cannot be caught/found easily, others have unknown or hard to recreate habitat requirements
-Habitat restoration/new habitat creation when mining has ended is often carried out, eg wetland nature reserve in mine void. Many countries, eg UK—> this is a requirement in order to gain permission for mine
-Approx 25% sand & gravel used in UK is dredged from seabed. To reduce damage to benthic (living on ocean floor) organisms, dredging is often undertaken where strong currents move sediments around so few organisms found here

Question 50

How does mineral exploitation cause loss of amenity and how is this counteracted?

Answer 50

-Mining changes landscape, can create aesthetic problems for local communities
-Effects may be reduced by landscaping & tree planting
-Mine closes—> can be turned into community resource so long term amenity value may be > area before mining took place?

Question 51

How does mineral exploitation create dust and how is this counteracted?

Answer 51

-Blasting & vehicle movements creates dust—> lifted into atmosphere
-Water sprays—> used to limit dust by making dust particles heavier so they settle & by wetting them so they clump together

Question 52

How does mineral exploitation cause noise problems and how can this be counteracted?

Answer 52

-Mine vehicles & rock blasting= main sources of noise
-Embankments/‘baffle mounds’ built around mine help absorb + deflect noise
-Blasting in mines—> doesn’t usually take place day & night but can be disturbing to local communities, esp if unexpected. an be counteracted by basting at set times

Question 53

How does mineral exploitation cause turbid drainage water and how can this be counteracted?

Answer 53

-Suspended soil particles in mine drainage water—> reduces light penetration into rivers & lakes
-Sediments can cover & kill plants & animals
-Turbidity of drainage can be reduced—> using sedimentation lagoons, water stands still for long enough for solids to sink, so outflow water= low turbidity

Question 54

What is spoil and what does it include?

Answer 54

Solid waste material left behind by mining, can include overburden material, unwanted material extracted w/ mined mineral & solid wastes from chemical processing of mineral.

Question 55

What problems can spoil disposal create and how can this be counteracted?

Answer 55

-Aesthetics: spoil heaps can damage scenic beauty of area. Landscaping—> spoil heaps looks more natural, blend in w/ surrounding area
-Stability; lack of surface compaction—> reduces surface stability, cause erosion. This can be reduced by landscaping to reducing gradients, adding soil, nutrients & planting w/ trees/other vegetation. If spoil heap= waterlogged: may become unstable—> landslides. Eg= Aberfan, S Wales, 1966
-Leachate; rainwater percolating through soil can dissolve toxic metals & sulfides—> produces acidic leachate solutions. Toxic metals normally insoluble when inside rocks may be dissolved= become mobile
Many toxic metals—> more soluble under acidic conditions. To manage= mine drainage water can be passed through filer bed of crushed limestone to immobilise metal, prevent from carrying to river

Question 56

In what ways can mine sites be restored?

Answer 56

-New uses may be found for sites previously used for mining & mineral processing → use depends on its location, access, topography & any residual issues like spoil heaps w/ toxic wastes
-Many sand, gravel & clay pits have been flooded & developed as wetland wildlife reserves
-Urban development on mine sites may be possible if ground = stable. If metal wastes are present, site may be more suitable for industrial use than housing
-Agricultural use may be possible is landscape isn’t too steep/ uneven, no toxic materials are present & soil = sufficiently fertile.

Question 57

What have been some improvements made in exploratory techniques within mining?

Answer 57

-Better remote sensing image resolution; newer satellites may carry improved sensors → generate greater number of image pixels
Multispectral sensors detect greater range of wavelengths of visible + infrared light, giving more detailed info on mineral composition of Earth’s surface

-Portable field equipment; lab techniques have become smaller, more portable as electronic components become lighter, more powerful batteries developed & energy consumption ↓
This equipment is available for infrared spectroscopy, X-ray fluorescence & radiation detection: save time as results available immediately, no need to wait for lab results to be received

Question 58

What have been some improvements made in exploitation methods within mining?

Answer 58

-Mechanisation; deep mining
Using machines allows mining underground, where it may be too hot /dangerous for people
-Open-cast mining;
Larger machinery in open-cast mines allows overburden & minerals to be extracted more quickly & cost-effective. Excavators; 13,000t+, trucks; carry up to 300t. Machinery of this size allowed deeper open-cast mines to be developed w/ mines 600m+ in depth being possible for more valuable minerals.

Question 59

What is the normal method of extracting a metal from its ore and why does this need to be replaced?

Answer 59

-Smelting it; chemical reduction at high temperatures
-Amount of energy needed increases rapidly as ore purity declines
-So, economically viable exploitation may only be possible if new methods can be developed, not relying on high temperatures/energy inputs

Question 60

What is bioleaching and what are some examples of this technique?

Answer 60

-Use of living organisms to extract metals from their ore, eg;
-Acidophilic bacteria can be used to extract metals like copper, zinc, lead & gold from low grade sources. Bacteria oxidises sulfide ores, make sulfuric acid, dissolving the metals
-Aspergillus fungi can be grown on scrap metal components, fly ash from incinerators & catlytic converters. Fungi make acid that dissolve metals like nickel, copper, lead & tin
-Metals in solution made by bio leaching can be separated by electrolysis/carbon filters

Question 61

What is phytomining and how is it carried out?

Answer 61

-Some plants absorb metals ions from soil/water & concentrate them in their leaves
-Can be used as method of decontaminating polluted sites & commercial extraction of metals
-Once plants have absorbed metals, vegetation= harvested & incinerated
-Concentrated metals in ash can be dissolved w/ acids, then separated by electrolysis

Question 62

What is iron displacement and how is this carried out?

Answer 62

-Iron= more reactive metal than copper & will displace copper ions from solution
-Solid iron go—> solution as copper ions are deposited as solid copper metal; can be collected

Question 63

What is leachate collection and how are metals extracted this way?

Answer 63

-Rainwater percolating through spoil heaps dissolves soluble metal ions
-Draining leachate can be recirculated through soil heaps to increase conc of metal ions in solution
-When conc= high enough, metals can be extracted from solution via electrolysis

Question 64

Why are rare earth metals important and how can they be exploited?

Answer 64

-Used in small amounts in many important applications, especially electrical/electronic appliances; smartphones, wind turbines
-Exploitable deposits on land= limited, mainly found in China
-Chemical application= complicated, produces large amounts of toxic wastes
-New techniques developed like bacterial absorption (dissolved ions of rare earth metals become more conc as absorb onto cell surfaces of bacteria, eg Bacillus subtilis. Metals can be separated by washing them off bacteria w/ acidic solutions, w/ diff metals being washed off at specific pHs
-Deep sea sediments—> relatively high conc of rare earth metals, incl gadolinium, lutetium, etc. There’s currently no viable method for exploiting these deposits; but may be developed as demand for rare earth metals increases

Question 65

What is polymer absorption and how can it be used to extract metals?

Answer 65

-Metal ions dissolved in seawater will absorb—> surface of some polymers, can be collected
-Synthetic polymers can be used, so can natural (eg lignin from wood)
-^Method is being developed to extract uranium, may give low-energy method of producing fuel for nuclear power industry

Question 66

What are polymetallic nodules and how can they be exploited despite previously being inaccessible?

Answer 66

-Also called manganese nodules; metal-rich nodules found on seabed of many oceans. Most= up to 5-10cm in diameter, found at depths of 4000-5000cm
-Origins not fully understood, may have been formed by chemical precipitation of metals around small solid object, eg marine organism. Contain about 30% manganese w/ smaller amounts of iron, nickel, copper, etc.
-Large scale exploitation= expensive, requires international agreement on ownership of seabed & resources

Question 67

What are the environmental impacts of recovering polymetallic nodules?

Answer 67

-Will disturb seabed, kill benthic organisms living there
-Separating nodules from seabed sediments—> increase turbidity of water w/ unknown consequences
-Re-deposition of sediments= likely to kill filter feeders + cover & kill benthic organisms

Question 68

Where do material wastes come from and how can they be recycled?

Answer 68

-Pre-consumer wastes; eg waste trimmings made by cutting/stamping machines
-Post-consumer wastes; eg discarded consumer products
Most materials in domestic waste can be recycled if separated. Most effective when undertaken by public before collection, as prevents reduction in quality due to mixing of wastes, eg paper & food waste

Question 69

How is transport a problem within recycling schemes?

Answer 69

-Extraction of aluminium ores involves bulk resources where bulk transport can be used to create major economies of scale & lower until cost.
-Recycling may involve collection & transport of smaller quantities of materials; more expensive, bulk transport not possible.
-Recycling materials= lighter than OG raw materials

Question 70

How are Labour costs a problem within recycling schemes?

Answer 70

-Processing smaller quantities of materials increases labour costs.
-Recycling work doesn’t usually require level of skills/training extraction requires, so labour costs= lower

Question 71

How is separation a problem within recycling schemes?

Answer 71

Alloys of mixed metals can’t be easily separated so recycled aluminium alloys can’t be used where pure aluminium is needed

Question 72

How is identification a problem within recycling schemes?

Answer 72

It is intensive & slow work to identify composition of recycled materials where composition is important for reuse

Question 73

How are energy costs a problem within recycling schemes?

Answer 73

Recycling aluminium saves energy needed for extraction of aluminium of bauxite but saving may be exceeded by energy used for transport of smaller quantities quantities—> collected

Question 74

How is public cooperation a problem within recycling schemes?

Answer 74

Successful post-consumer recycling schemes require public cooperation to separate wastes

Question 75

How are waste losses a problem within recycling schemes?

Answer 75

Not all used materials can be recycled, some= unavoidably lost where litter is discarded/placed in general waste for landfill

Question 76

Why is the Cradle to Cradle design used and what does it involve?

Answer 76

-If lifetime of minerals in use can be extended, need to exploit reserves= reduced
-Involves design of products so materials used are able to be reused at end of useful lives
-Includes easy separation of components & identification of materials