Mining and Mineral Resources

B. Describe the different types of mining and associated processes

a. First step: Find an ore deposit!Companies use instruments that measure gravity, magnetism, and radioactivity and pictures from satellites and planes

b. Next: Take samples

c. Determine how much ore is present

d. Open a mine ??

A mineral deposit must have 100 to 1000 times the concentration of the mineral than ordinary rocks do to be feasible to mine!

Surface mining

• Main Types of Surface Mining– Strip Mining

• Removal of large strips of overlying rock and soil to reveal coal.

– Open-Pit Mining• Removal of rock and soil creating a vast pit where coal can

be extracted.– Mountaintop Removal Mining

• Removal of mountain tops with explosives. Land made flat after reclamation.

– Highwall Mining• A continuous miner cuts holes horizontally into the coal

formation.

1. Room-and-pillar mining.

Gigantic areas are excavated and

small areas remain untouched to hold

up the ceiling

2. Longwall MiningIn this type of mining, a machine moves along the face of rock and shears off the stone onto a conveyer

Hydraulic arms hold up the ceiling until the machine moves forward then the ceiling collapses

3. Solution Mining

Hot water is used to dissolve the ores

and bubbles lift it to the surface

B3. Describe three methods of surface mining

1. Strip mining

This mining occurs when the ore is near the surface

and layers of rock covering it, called

overburden, can be stripped away by

machines

2. Quarrying

Method of

cutting larger

sections of rock out of

the ground

Granite, limestone, and marble

3. Solar Evaporation

This is done by placing seawater into enormous shallow ponds, the sun then evaporates the water and leaves the sodium chloride behind.

B4. Define placer deposit, and explain how placer deposits form.

Placer deposits are minerals concentrated by wind and water into surface locations

Areas of the river where the current

slows collect more dense minerals like

gold and silver

Where does the coal go after it leaves the mine?

• The coal is shipped by train or barge to its destination.

• The coal may be refined before shipping– Washing with water or a chemical bath to remove some

impurities

• When the coal arrives at the power plant, it is pulverized into a heavy powder that is suitable for burning.

How is coal used at a power plant?

B5. Describe the steps that take place in smelting an ore.

1.The ore is mined and then melted at a smelter~ 1000-3000 degrees in furnaces

2.A material called flux is added which bonds to the useless minerals (slag) and floats to the surface

3.The valuable mineral sinks to the bottom and then poured off and cooled to form ingots

pollution

C. Describe the environmental impacts of mining and what we can do to change

them.

1. Air and Noise Pollution

2. Water Pollution

Acid mine drainage

Can kill fish, other aquatic animals and plants for hundreds of miles downstream

3. Displacement of wildlife

Mining, especially open-pit, disrupts

huge areas of land

4. Erosion and sedimentation

Large piles of excess rock

called tailings litter large areas near the mine

Some tailing piles are so large that they fill valleys!!

5. Soil degradation

Soil removed by the mining process is often

damaged and not used in the reclaiming process.

The reclaiming process returns

the land to nearly its original condition once

mining has ceased

6. Subsidence

This collapsing occurs at ground level when the tunnels or rooms below

ground cave in and the layers of rock above collapse into

the vacated space

7. Underground mine fires

Usually in coal mines or seams, coal catches fire from

lightning or chemical reactions. These may burn for

centuries!!

Coal seamsSmoke from coal seam fire

Coal seam on fire

C2. Name four federal laws that relate to mining and reclaiming mined land

Mining operations are governed by these laws:

1. Clean Water Act

2. Safe Drinking Water Act

These acts protect water

quality

3. Comprehensive Response Compensation and Liability Act

This act prevents hazardous wastes

from being released

4. Endangered Specie Act Protects endangered plants

and animals

C3. Define the term “reclamation”

Reclamation is a process that returns the land to pre-mining conditions

Most of the time, when the mining company is done with it, the pit is used as a landfill.  A landfill is used as a dump to get rid of our garbage.  When it is filled with garbage, it is covered over with layers of dirt.  After the garbage rots a long time, the land can be used again. 

Some times the crater is filled with water – a lake is born.

C4. Describe two ways in which state governments regulate mining

1. States regulate mining through a permitting process

2. States assess fines for

noncompliance