Coal mining: Comprehension Questions

1.  Underground mining is more dangerous because there can be movements that could destroy the mine and let many people die. But on the other hand, surface mining is on open air, not like underground mining that is underneath the ground.
2. In surface mining, they use trucks, large earth moving machines and bulldozers.
3. The tunnels are used for traveling throughout the mine, moving coal from place to place and allowing air to circulate in the mine.
4. A conveyor belt takes coal out of the mine.
5. There are three types of underground mines: slope, drift, and shaft. 

Slope:  When the coal seam is close to the surface but too deep to use
surface mining, a slope mine can be built. In a slope mine a tunnel
slants down from the surface to the coal seam.

Drift: A drift mine is built when the coal seam lies in the side of a hill or mountain. Drift mines may also be built in a surface mine that has become too deep.

Shaft: These mines may be 125 to 1,000 feet deep. A large hole, or shaft, is drilled down into the ground until it reaches the coal seam.

Glossary:

1. Dragline: a large machine used in the surface mining process to remove overburned, or layers of earth and rock, covering a coal seam.
2. Subbituminous: type of coal with lower sulphur content than other types and so is cleaner-burning found mainly in western states and of US and Alaska.
3. Overburned: layers of earth and rock covering a coal seam.
4. Drift mine: type of mine created to access coal buried deep underground, charecterized by an entrance that is horizontal tunnel into the sean of coal.
5. Deep mine: type of mine created to access coal buried deep underground, charecterized by a set of shafts dug straight down to the coal.