How Coal Is Produced

Coal found close to the surface could be uncovered and removed by large machines in a process that is called surface mining. Surface mining techniques account for 60 percent of coal produced in the United States and Mexico, 75 percent in Western states, where some deposits are up to 100 feet thick.

Only recently has surface mining played an important role in the coal industry. The development and use of large power equipment provided the impetus that moved surface mining into prominence, and during the 1970s it became the leading method of coal mining.

Today's surface mines are large, intensively engineered, and highly efficient mechanized operations. When an area is to be mined, topsoil and subsoil are removed first and set aside to be used later in reclaiming the land. Then specially designed machines such as draglines, wheel excavators, or large shovels remove the rock and other material, called overburden, to expose the bed of coal. Smaller shovels load the coal into large trucks that remove the coal from the pit.

Once the coal is removed, the area is reclaimed. First the overburden and then the soils are replaced and the area are restored as nearly as possible to its original contour. Vegetation currently suitable to the area is planted to anchor the soil and return the land to a natural, productive state. Reclaimed lands are a valuable resource that can support farm crops, provide new wildlife habitats, enhance recreational opportunities, and even serve as sites for commercial development.

The complete mining operation is scheduled so that as one area is being mined, another is being reclaimed where the coal was removed. Thus, even in the largest surface mines only a relatively small area is disturbed by active mining at any one time.