Surface Mining.

Surface Mining.

1. Strip Mining.

Strip Mining is used when coal is near the surface of when the overburden is unstable. As mining progresses, the overburden is placed in the previous mine cavity. The mining is done in long, narrow strips. The waste, dirt, and rock that they take off of the top of the next strip is to put on top of the last one. Explosives are put in holes and blasted. The sizes of the chunks usually matter, considering, the miners want to be able to move the larger pieces with machinery. Advantages include easier, faster work. Most of the time, bigger quantities. Disadvantages are it ends up hurting the areas around the strip mining. The rock, trees, gravel, vegetation, etc... is dumped into the mine or areas around the mine. When it rains, the rain floods the mine, travelling to water sources and contaminates the water. To reclaim land, mining companies need to fix the land how it was before hand. Different mineral ores and coal is mined this way. 

2. Contour Mining.

Contour mining is a type of surface mining that follows the contour of a hill or mountain leaving terraces in the mountainside. This method is often used in areas that has steep terrain. The limitations of contour mining are both economical and technical. When the operation reaches a predetermined stripping ratio, it is not profitable to continue(disadvantage). Depending on the equipment available, it may not be technically feasible to exceed a certain height of high wall(disadvantage). At this point, it is possible to produce more coal with the augering method in which spiral drills bore tunnels into highwall laterally from the bench to extract coal without removing the overburden. This method could highly benefit states with such mountainous ranges(advantage). 




3. Mountaintop Removal. 
Tops of hills are removes to access horizontal  coal seams. Overburden is pushed to areas between high elevators. Following reclamation, the original contour is not restored. This is the most controversial mining method(advantage). This method of mining usually leaves mountain tops to flat plateaus. Many ecosystems and habitats are largely damaged and possibly permanently damaged. This method could cover up or stop flowing streams which could disrupt other actions being used with the stream.  


Hyperlink to access more knowledge on this subject.


Photocredits:
(Strip Mining) library.thinkquest.org
(Contour Mining) contourmining.com
(Mountaintop Removal) mountainroadshow.com