Before award-winning reclamation
can be planted, the coal must first be mined. However, before coal can be removed
from the ground, the topsoil and dirt above the coal has to be removed. The topsoil
is removed using scrapers. Generally, the topsoil is removed AHEAD of the pit
and carried around BEHIND the pit and placed on reclaimed areas (or backfill).
The dirt which lays on top of the coal (or overburden) follows the same
pattern. The overburden is approximately 120 feet thick and is excavated in three,
40-foot benches. (Just click to see and hear a shovel loading a truck. 5,976
kb.)
After the overburden has been removed, it is carried around behind the
pit and placed in the spot where coal was removed. Now, the coal is exposed
and can be dug out. The coal is first blasted to make it easier to remove it.
(Click to see and hear a real coal blast! 1,267kb)
Mine
trucks used in the Wyoming coal industry get bigger and bigger.
To the left and right are photographs of a Liebherr 360 ton (327 metric ton) haul truck. This unit is powered by a 2750 horse power engine and weighs 443,000 pounds empty. (These photographs are courtesy of Liebherr Mining Equipment Company.
