[Hoot Gibson]

Ty, Ive just always been told that major coal companies prefer surface mining because its cheaper and requires less workers.

In general, companies will always try to produce a product to maximize profits, and I am not disputing that fact. The point I try to make is that in many (and probably an increasing number) of cases, the conditions dictate the mining method. For example, if a block of coal reserves has an overburden depth of zero to 100 feet and it contains 6 feet of coal in seams ranging from 6 to 18 inches separated by 20 feet of shale partings, then it may be surface minable but it is not deep minable. The reason is that transporting, processing deep mined coal to remove rock is very expensive and there is a limit to the percentage of "rejects" that a coal preparation plant can economically remove.

Even if a coal seam is fairly clean, if the overburden is shallow enough to allow surface mining, then the roof conditions will often not allow the coal to be mined by underground methods. In other cases, thicker seams that underlie a seam lying higher on the hill may have been mined out previously. Subsidence caused by the previous mining sometimes renders the higher seam unminable by deep mining methods. Generally, if two seams are located within 20 feet in elevation of each other, only one of them may be deep mined - although much depends on the type of rock separating the seams.

The bottom line is that choosing a mining method is never as simple as surface mining opponents make it sound.