Earth's resources

Question 1

define the term ‘gangue mineral’

Answer 1

gangue minerals are such that have no economical value, or the impurities in or around a mineral. Is usually the waste rock around the mineral of economic interest.
e.g. sand, quartz, dirt, etc.

Question 2

define what a mineral deposit/ore body is.

Answer 2

A mineral deposit/ore body is defined as a volume of rock that contains one or more elements or minerals sufficiently above the average crustal abundance to be economically mined (a profit can be made if mined).

Question 3

List 4 reasons why we cannot accurately estimate how many reserves we have.

Answer 3

1. New discoveries
2. Don’t know how much we will use (usage fluctuates)
3. Unknown amount
4. New technologies to extract new materials

Question 4

Define what resources and reserves are.

Answer 4

Resources - What we currently know exists, but is not economical

Reserves - Materials that we can economically mine

Question 5

What is a hypothetical resource?

Answer 5

We are certain that the minerals are there but we aren’t 100% certain.

Question 6

How can we use more copper than we mine each year?
(Applies to more than copper)

Answer 6

Recycling the material.

Question 7

What does economic and not economic mean?

Answer 7

Economic
Can make a profit by mining the reserve.

Not economic
Cannot make a profit/is too expensive to mine.

Question 8

Can resources become reserves? How?

Answer 8

Yes they can. As other reserves are used up and the demand continues to grow, resources can become reserves.

Question 9

Give 4 reasons as to why renewable sources of energy don’t contribute to the global demand.

Answer 9

1. Low output of energy
2. Not as profitable
3. Still has environmental impact
4. Have to convince people (noise pollution)

Question 10

List 5 characteristics of a good placer deposit

Answer 10

1. High density
2. Insoluble
3. Resistance to abrasion (deform not shatter)
4. Little cleavage, minimal breakage or easy splitting
5. Hard, hardness scale 1-10, diamonds are 10.

Question 11

Name the four types of placer deposits and where they are found

Answer 11

1. Eluvial (Next to vein on hill side)
2. Colluvial (Down hill side, broken off of vein)
3. Marine (Along coast, going with the current)
4. Alluvial (River bed, inside of the bend or plunge pool)

Question 12

Explain the process of a magmatic chamber cooling and the accumulation of minerals

Answer 12

As the magma body rises through the mantle it cools, and minerals crystallise, forming layers of different minerals.

Layers are dependent on melting point and density (highest melting point cools first and begins sinking first, however denser minerals may still make it to the bottom first)

Question 13

Suggest a new use for an open cut mine

Answer 13

Fill in the open cut mine with the gangue minerals and waste materials, and use this open land (free of tall trees and buildings) as a solar plant. The existing power grid that once fed the mine could be converted to send the electricity the other way. Access roads around the mine can be used to maintain the solar plant.
Would save another (untouched) piece of land being disturbed.

Question 14

List the 4 stages of coal

Answer 14

1. Peat (Beginning of coal process, swamp vegetation compressed and buried by layers of sediment)
2. Lignite (Low ranking coal)
3. Bituminous (Medium ranking coal)
4. Anthracite (High ranking coal, up to 90% carbon, most reactive)

Question 15

What is meant by the ranking of coal?

Answer 15

The carbon percentage. If it has a high calorific value it gives off a lot of heat, therefore more valuable.

Question 16

What are volatiles and what do they do?

Answer 16

Volatiles are nitrogen, hydrogen and oxygen and are a part of the coal.
They allow for minimal ignition energy making it easier for it to burn.
The more the better.

Question 17

List 3 factors which affect the formation of coal

Answer 17

Pressure
Temperature
Time

Question 18

Major part of coal question is what?

Answer 18

A graph.
Think carefully about it, take your time to figure it out before answering.

Question 19

What does it mean to recontour an old mine?

Answer 19

To make it seem like the piece of land was never touched

Question 20

What does reclamation mean?

Answer 20

To give an old mine a new beneficial use

Question 21

What is the order of evaporites?

Answer 21

1. Calcium carbonate (least soluble)
2. Gypsum
3. Halite
4. Bittern salts (highest solubility)

Question 22

Where do evaporites form?

Answer 22

Hot arid climates, near the coast in enclosed gulfs or lagoons.

Question 23

How do evaporites form?

Answer 23

Abnormally high tides allow sea water to flood into the lagoon/gulf over the high embankments replenishing the water level VERY occasionally. The basin sinks, allows for more water, evaporates and that process repeats.

Question 24

List the two kinds of oil traps

Answer 24

Anticline and fault trap

Question 25

What is the order of the layers found in an oil trap?

Answer 25

Gas, oil, water - GOW

Question 26

What is meant by a rock being porous or pervious?

Give examples

Answer 26

Porous
Water flows through pores which are gaps between the particles

Pervious
Have cracks or faults so water and oil can flow directly through the rock

Rocks can be one or the other or both

Examples of pervious and porous rocks are limestone and sandstone (these can be both)

Impermeable and Impervious rocks are mudstone and clay, but these are sometimes porous.

Question 27

Describe an anticline trap

Answer 27

An arch in the rock layers which were originally laid down flat but the earth’s movement bent it into an arch. Oil and water moves its way through the permeable rock to the top where it is stopped by the cap rock.

Rock which holds the oil is known as the reservoir rock (mudstone and clay)

Question 28

Describe a fault trap

Answer 28

Movement from the earth causes a break in the sediment layers. A fault line is created and the oil and water rises through the permeable rock, to then be stopped by the cap rock.

Rock which holds the oil is known as the reservoir rock (mudstone and clay)