Advantages: cheap and easy
Disadvantages- tunnels collapse
Shaft Mining- common method of accessing coal with elevators, deeper than 1000 feat below the surface
advantages: ventilation is okay, cheap
disadvantages: drilling the holes and charging them poses a huge risk
Room and Pillar Mining- half of coal left behind to support roof, Disadvantage: pillars put pressure on adjacent pillars leading to roof collapse. Roof falls are a constant danger.
advantages: high degree of flexibility, process is repititous.
disadvantages: cost of maintenance is very high
Continuous Mining- Machines usedwith drift mining or pillar mining, one miner operates the machine, varieties of machines used since 1940's. Paired with conveyor systems to transport coal out of the mine.
advantages: constant flow of caol out of mine, uses less workers.
disadvantages: sometimes the machines arent alway productive, then one loses money to pay for the machines to run without results
Long Wall Mining- highly effecient, huge machines support roof with hydraulics and once the coal os removed, the machine retreats and roof caves in.
advantages: can gather a lot more coal
disadvantages: more dust is generated at a dangerous rate
http://library.thinkquest.org/05aug/00461/shaft.htm
No comments:
Post a Comment