The Lithosphere - Mineral Resources - Physical

Question 1

What is hydrothermal Deposition?

Answer 1

1) Rainwater percolates soil.
2) Water heated (100 degrees c+) but no evaporation (high pressure).
3) Minerals from magma dissolve in super-hot water.
4) Water moves away from hot magma - as it cools minerals crystallise out of solution (in veins).

Can form: Tin, copper, lead, silver, gold etc.

Question 2

What are metamorphic processes?

Answer 2

Igneous processes and tectonic movements of crustal plates can alter existing rocks. Produces metamorphic rocks.

Need to know:
Limestone turns to marble under high temps and pressure.
Mudstone turns to slate under high pressure.

Question 3

What are proterozoic marine sediments?

Answer 3

Dissolved iron compounds become oxidised (O2 formed from photosynthesising bacteria 2.5-1.8 billion years ago). Produces insoluble iron oxide deposits.

Can also form haematite and magentite.

Question 4

What are alluvial deposits?

Answer 4

Materials that were carried and separated by flowing water. Depends on velocity of water and density of solids.

Gold, diamond, tin ore, gravel, clay.

Question 5

What are evaporites?

Answer 5

Bay of ancient sea becomes isolated = water evaporates, leaving crystallised minerals. Also form from rivers.

Halite (sodium chloride).

Question 6

What are biological sediments?

Answer 6

Living organisms form mineral deposits. Often concentrate minerals that can be deposited in sedimentary rocks.

Limestone/chalk (shells of marine organisms).
Coal (terrestrial vegetation).
Crude oil / natural gas (marine organisms)

Question 7

What is a resource?

Answer 7

The potential materials that are available to be exploited.

Question 8

What is a reserve?

Answer 8

The part of the resource that is currently available to be exploited (based on current technology and market price).

Question 9

What is the cut off ore grade?

Answer 9

The lowest purity that can be mined economically at current market price.

Question 10

What is Lasky’s Principle?

Answer 10

As the linear purity of a deposit decreases, there is an exponential increase in the amount of the material that is included.

Question 11

How would the ‘cut-off ore grade’ change if market prices rise?

Answer 11

It would drop (lower) as even though it’ll take more energy to extract, it’s worth it due to the increase in price.

Question 12

What is remote sensing and what are its advantages?

Answer 12

Using any technique to gain information without gaining direct samples.

+ Less time consuming.
+ Works out cheaper.

Question 13

What is IR spectroscopy? (remote sensing)

Answer 13

Different minerals emit Ir radiation at different wavelengths.

Question 14

What is gravimetry? (remote sensing)

Answer 14

Gravimeters detect variations in gravity caused by variation in density and mass (igneous rocks more dense).

Question 15

What is magnetometry? (remote sensing)

Answer 15

Magnetometers detect magnetic rocks such as ores of cobalt.

Question 16

What are seismic surveys? (remote sensing)

Answer 16

Involve waves produced by controlled explosions, or a seismic vibrator on the surface. Gives info about depth, density, and shape.

Question 17

What is resistivity? (remote sensing)

Answer 17

Measuring difficulty with which electricity passes through a material.

Question 18

What are the setbacks of remote sensing?

Answer 18

These can be unreliable sometimes - at some point you’ll have to go out and actually find them + measure it.

Question 19

What are the 2 non remote sensing techniques but are needed alongside remote sensing?

Answer 19

Trial drilling - Digging out a sample core from the ground. Very expensive but produces physical samples of rock.

Chemical Analysis - Laboratory tests confirm chemical composition and purity of minerals in rock samples.

Question 20

Mine viability: Ore purity

Answer 20

Purity of ore affects financial costs of exploitation and environmental impacts.
If low = more rock mined, more waste, more energy needed, more pollution.

Question 21

Mine viability: Chemical form

Answer 21

Affects ease of chemical extraction of metal.

Question 22

Mine viability: Overburden and hydrology

Answer 22

Hard overburden may require blasting = increases damages and cost.
Loose overburden may increase landslide risk.
Higher precipitation will increase drainage costs.

Question 23

Mine viability: Depth

Answer 23

Cost rises rapidly as depth increases. Sides of mine cannot be vertical (it’ll collapse), so amount of waste removed increases as you reach mineral.
More pumping will be needed (when rains) = more cost.

Question 24

Mine viability: Economic viability

Answer 24

Has to be economically profitable - The Cut-Off Ore Grade (COOG).

Question 25

Mine viability: Transport costs

Answer 25

Affected by distance to market, ease of bulk transport, presence of suitable existing transport infrastructure etc

Question 26

Mine viability: Market economics

Answer 26

Market demand and sale value of minerals control the economic viability of exploiting a specific mineral deposit. Demand can rise and fall quickly.

Question 27

Why is the land that is leftover from mining operations often unsuitable for agriculture?

Answer 27

• Previous toxic metals contaminate the soil = plants would die or become toxic to eat.
• Water sources could be contaminated.
• It’s quite steep (slopes), won’t get a tractor up them.
• Will be rocky, unfertile, not much soil for planting.

Question 28

How do sedimentation lagoons reduce environmental problems?

Answer 28

Acts as a place for all the particles and sediments to go so they can settle - reduces the turbidity of water.

Question 29

How does tree planting on spoil heaps reduce environmental problems?

Answer 29

Helps soil heaps to blend in with their surroundings and reduces erosion.

Question 30

How do baffle mounds reduce environmental problems?

Answer 30

Helps absorb and reflect noise and thus reduces the noise.

Question 31

How does water spraying reduce environmental problems?

Answer 31

Makes dust particles heavier so they settle. Limits dust.

Question 32

How can the pH of a mine drainage water be measured?

Answer 32

A calibrated pH meter.

Question 33

What are some environmental issues of mining?

Answer 33

• Noise.
• Spoil heaps destroy the view (look unnatural).
• Dust can enter atmosphere and smother plants and animals (also bad to breathe in).
• Sedimentation (increases water turbidity and can smother and kill plants and animals).

Question 34

Methods to improve the future of mineral supplies: Increased exploration.

Answer 34

1) Remote sensing e.g. improved satellites detecting greater range of IR and visible light.

2) Portable field equipment - saves time as reduces need for laboratory analysis.

Question 35

Methods to improve the future of mineral supplies: Improved mechanisation.

Answer 35

Mines can be mechanised (e.g. lifts) to make exploration quicker.

Question 36

Methods of extracting low grade ores: Polymer absorption.

Answer 36

Metal ions dissolved in seawater absorb onto surface of a polymer - synthetic or natural (e.g. wood and chitin).

Question 37

Methods of extracting low grade ores: Leachate Collection.

Answer 37

Water drains through spoil heap - dissolved minerals/metals extracted by hydrolysis.

Question 38

Methods of extracting low grade ores: Bioleaching.

Answer 38

Extracting minerals/metals using organisms (like bacteria).

Question 39

Methods of extracting low grade ores: Phytomining.

Answer 39

Extracting metals/minerals taken up by plants (through oxidation).

Question 40

Methods of extracting low grade ores: Iron displacement.

Answer 40

Iron displaces copper, can be extracted with electrolysis.

Question 41

The extraction of rare earth metals.

Answer 41

• Can be used in electronic appliances.
• Chemical separation of these are difficult and produces toxic waste.
• Bacterial absorption can be used where dissolved ions from solution become more concentrate in bacteria - washed off bacteria in acidic solution.
• Different metals wash off at different pH’s.

Question 42

Extracting previously unavailable deposits: Polymetallic Nodules

Answer 42

• These are metal-rich nodules found on seabed around 4-5km down.
• Thought to have formed by chemical precipitation of metals around a small solid object.
• Contain about 30% manganese, with small amounts of iron, nickel. copper, cobalt, titanium.

Question 43

What are the disadvantages of polymetallic nodules?

Answer 43

• Large scale exploitation will be expensive.
• Land may be owned and thus none of this allowed.
• Disturbance of seabed = loss of benthic (bottom-dwelling) organisms.
• Increased turbidity.
• Sediment that is redeposited may cover and kill filter feeder = no food for the larger organisms.

Question 44

How can the waste generated from new resources be reduced?

Answer 44

• Improving extraction efficiency.
• Use of offcuts.
• Reduced material use in manufacture.
• Replacing scarce materials with more abundant or more easily recyclable versions (substitution).

Question 45

What are the issues with recycling aluminium?

Answer 45

• Not all used materials can be recycled.
• Energy used to transport and recycle must be less than needed to extract it.
• It will be less energy efficient if only small quantities are used.
• Alloys are not easily separated = recycled alloys cannot be used where pure aluminium is needed.
• Public recycling schemes require cooperation.

Question 46

What is the cradle to cradle design concept?

Answer 46

Involves design of products where the materials can be easily removed at the end of their lives, e.g. easily removable metal plating or screws.