A2 Economic Deposits, Extraction and Processing

Question 1

Ore

Answer 1

the rock containing valuable metal(s) that is economic to mine.

Question 2

Resource

Answer 2

a useful and valuable natural material.

Question 3

Mineral resources

Answer 3

can be metallic and non- metallic or industrial minerals.

Question 4

Reserves

Answer 4

the amount of the resource that can be extracted at a profit using existing technology.

Question 5

Ore deposit

Answer 5

an accumulation of metal that may be economic to mine.

Question 6

Average crustal abundance

Answer 6

describes the amount of metal in ‘average’ continental crust.

Question 7

Concentration factor

Answer 7

the amount by which the metal is concentrated to make an ore deposit.

Question 8

Ore mineral

Answer 8

a mineral containing valuable metal(s).

Question 9

Gangue mineral

Answer 9

a low-value waste mineral.

Question 10

Grade

Answer 10

refers to the concentration of valuable mineral within an ore.

Question 11

Cut-off grade

Answer 11

the grade below which it is uneconomical to mine.

Question 12

Secondary enrichment

Answer 12

occurs when metals are leached from within surface rocks and precipitated just below the water table.

Question 13

Chemical weathering

Answer 13

the in situ breakdown of rocks at the Earth’s surface due to chemical reactions.

Question 14

Leaching

Answer 14

where ions are dissolved from rocks and carried downwards in solution.

Question 15

Gossan

Answer 15

an insoluble cap of iron oxides at the surface of a mineral vein.

Question 16

Oxidising

Answer 16

describes oxygen-rich conditions, allowing elements to combine with oxygen to form oxides.

Question 17

Reducing

Answer 17

describes oxygen-poor, anoxic conditions.

Question 18

Enriched deposit

Answer 18

a zone of high-grade ore just below the water table, formed by secondary enrichment.

Question 19

Porphyry

Answer 19

a large igneous intrusion with a porphyritic texture.

Question 20

Dredging

Answer 20

where material is scraped or sucked from the river or sea bed.

Question 21

Hydraulic mining

Answer 21

the use of high-pressure water jets to dislodge material.

Question 22

Geophysical anomaly

Answer 22

a departure from the normal value and may be positive or negative.

Question 23

Geochemical anomaly

Answer 23

a concentration of a metal above its normal background value.

Question 24

Dispersion

Answer 24

occurs when small amounts of metals are spread out around the ore deposit by the surface processes of weathering, erosion and transport.

Question 25

Catastrophic dilution

Answer 25

occurs where tributaries meet and water and sediment from other sources are added.

Question 26

Geographical Information System (GIS)

Answer 26

a computer application used to store, view and analyse spatial information, especially maps.

Question 27

Sustainability

Answer 27

using a resource so that it is not depleted or harmful to the environment, supporting a long-term balance in ecological and other systems.

Question 28

Non-renewable resources

Answer 28

do not renew themselves at a sufficient rate for sustainable economic extraction within a human lifetime.

Question 29

Open cast

Answer 29

extraction is mining from surface quarries.

Question 30

Shafts

Answer 30

vertical openings to an underground mine.

Question 31

Stope

Answer 31

the void left when the ore has been extracted from an underground mine.

Question 32

Flotation tailings

Answer 32

the waste rock fragments which do not attach to bubbles in the froth flotation process.

Question 33

Leachate

Answer 33

the liquid that drains or leaches from a landfill site.

Question 34

Pollution plumes

Answer 34

are zones of contamination, usually into an aquifer or water source. This can be from various sources, including leachate from landfill sites.

Question 35

Transuranic elements

Answer 35

have atomic numbers greater than 92, the atomic number of uranium. These are unstable and decay radioactively into daughter elements.

Question 36

Carbon sequestration

Answer 36

a process where CO2 is removed from the atmosphere and held in an alternative form, either solid or liquid.

Question 37

Open cast mining

Answer 37

also called open pit mining, surface mining technique, common technique, cheap, large volumes of material quickly, massive habitat destruction

Question 38

Stope mining

Answer 38

vertical or diagonal shaft, horizontal stopes (voids) directly into the ore body. Sometimes require roof supports depending on rock strength. More specialized equipment required, ventilation, water pumping. Far less habitat destruction that open cast.

Question 39

Longwall retreat mining

Answer 39

Ore body/coal seam exposed. A circular cutting tool, shearer, moves along the face. Ore material deposited onto a conveyer. Machinery and roof supports move forward towards the face. Area behind the supports is allowed to collapse.

Question 40

Kriging technique

Answer 40

A geostatistical computer model that creates a 3D block model of the deposit based on probabilities

Question 41

Downhole logging

Answer 41

Drilled borehole. Cameras and/or instruments collect geophysical data and samples for geochemical analysis.

Question 42

Geophysical survey techniques

Answer 42

Gravimetry, Magnetic, Electromagnetic, Resistivity

Question 43

Geochemical survey techniques

Answer 43

Stream sediments, Water, Soil, Vegetation

Question 44

Life cycle of a mine - 5 steps

Question 45

in situ leaching

Question 46

heap leaching

Question 47

froth flotation

Question 48

Formation of acid mine drainage

Question 49

Reducing AMD at source

Question 50

AMD diversion

Question 51

AMD active treatment

Question 52

AMD passive treatment

Question 53

Smelting of iron ore