A mining method often used by strip-mine operators where the overburden is too thick to be removed economically. Large-diameter, spaced holes are drilled up to 200 ft (61 m) into the coalbed by an auger. Like a bit used for boring holes in wood, this consists of a cutting head with screwlike extensions. As the auger turns, the head breaks the coal and the screw carries it back into the open and dumps it on an elevating conveyor; this, in turn, carries the coal to an overhead bin or loads it directly into a truck. Auger mining is relatively inexpensive, and it is reported to recover 60% to 65% of the coal in the part of the bed where it is used.