1.2 Extraction of rocks and minerals from the Earth

Question 1

Prospecting:

Answer 1

a process of searching for minerals by examining the surface of the rocks

Question 2

Remote sensing

Answer 2

• a process in which information is gathered about the Earth’s surface from above.
• Photographs of the area are taken from air
• The images are carefully analysed for mineral presence.
• Minerals can be identified because of their different colours
• Aerial photography can cover more ground than a person on the surface.

Question 3

Satellite signals:

Answer 3

• satellites send signals to the Earth’s surface and collect the reflected signals, indicating the presence of minerals.
• The unique radiation pattern is processed and analyzed by computers
• The system works in all weather conditions.
• The GPS gives the exact location.

Question 4

Geochemical

Answer 4

analyzing the chemical properties of rocks

Question 5

Geophysics

Answer 5

Seismic waves travel through Earth, bouncing off rock layers and returning to sensors that are on the surface. These waves record different patterns, revealing the minerals present in the layers below.

Question 6

Methods of Exploration for Minerals: (5)

Answer 6

1. Prospecting
2. Remote sensing
3. satellite signals
4. Geochemical
5. Geophysics

Question 7

Methods of extraction:

Answer 7

Surface mining
Sub-surface mining

Question 8

Surface mining includes

Answer 8

1. open-cast (open-pit, open-cut)
2. strip mining.

Question 9

Sub-surface mining includes

Answer 9

deep and shaft mining.

Question 10

What happens in surface mining (not steps)

Answer 10

Surface mining is a form of mining in which the soil and the rock covering the mineral deposits are removed.

Question 11

When is surface mining used?

Answer 11

This type of mining is used when a valuable deposit is located near the surface, often buried below a thick layer of overburden.

Question 12

Steps involved in open-cut mining (4)

Answer 12

1. The vegetation is removed
2. The rocks are broken and cut using explosives
3. The diggers are used to remove the loose rocks
4. The rocks are carried in trucks/ railway wagon

Question 13

When is sub-surface mining used?

used for gold and diamond

Answer 13

When mineral deposits are too
deep to be removed by surface mining

Question 14

Steps involved in sub-surface mining (4)

Answer 14

1. Sinking the vertical shaft down to the rocks containing minerals
2. Horizontal tunnels are dug down to the mineral layers
3. The loose rock is brought from the mines and piled up on the surface
4. the minerals are then transported away

Question 15

the factors that affect the decision to extract rocks and minerals (5)

Answer 15

1- The cost of exploration or extraction
2- geology
3- accessibility
4-environmental impact assessment
5- supply and demand

Question 16

The cost of exploration or extraction

Answer 16

The probable cost of extracting one tonne of ore

Deposits near the surface can be extracted
by open-pit mining. There are usually fewer technical difficulties to mining on a large scale using this method, which leads to a low extraction cost per tonne.

Deeper deposits can only be extracted by shaft mining. This is more costly to set up and maintain, so the cost per tonne will be higher than open-pit mining. Only deposits of high value can be mined economically in this way.

Question 17

geology

Answer 17

• The ore grade of the mineral
  If a mineral has a high ore grade or the size of the mineral is good they should consider extracting it

Question 18

accessibility

Answer 18

The accessibility of places where the mining operation will take place is important.:

• The climate tells whether the mining operation will be accessible or there will be obstructions
• transporation cost- Transporting the ore from the mine to processing plants can be difficult and expensive.

Question 19

 environmental impact assessment

Answer 19

• The mining company must be given a licence before extracting a deposit.
• For the license application to be approved, the company must have a plan to keep the
  loss of habitat minimal, and restoration of land proceeding with the completion of mining.
• The choice of site for mine waste should also be considered.

Question 20

Supply and demand:

Answer 20

• An increase in world demand for any mineral ore will elevate the prices.
• The profit from a working mine depends on changes in supply and demand.
• If the demand is too high, mines that were not profitable before become worth mining.
• If the demand falls, working mines may lose due to the transport and extraction expenses.