Mountaintop removal is a surface mining practice in which up to 800 feet of the top of a mountain is removed by blasting, and the material is placed in a nearby valley, in order to get access to thin seams of coal in the mountain. The coal is then removed by a dragline excavator, and the mountaintop is restored or, more usually, a variance is granted that allows the mining company to develop the site for another use. This practice is increasingly common in the eastern United States coalfields.