Strip Mining

Minerals located at or beneath the Earth's surface have long been used for building materials, energy sources, and a wide variety of products to further human development. There are numerous methods for mining these materials. Strip mining is one such method, which has proven to be efficient, economical, and, at the same time, controversial.

Strip mining is part of a broader category of mining techniques known as surface mining. These techniques, such as open-pit mining, quarrying, or high wall mining, involve moving massive amounts of earth from above the desired material. The rock, soil, and other material that cover the minerals are known as overburden. Each type of surface mining has methods in place to remove the overburden and, in some instances, to reclaim the site after mining operations are complete. Other than surface mining, rock and minerals are extracted from the Earth through underground mining, whereby shafts are dug into the seams, where valuable material is mined and then brought to the surface.

Most societies have engaged in extracting resources from the Earth for hundreds if not thousands of years. However, modern strip mining can trace its roots to the Industrial Revolution and the development of steam-powered, earth-moving equipment capable of removing large amounts of overburden. These early machines have evolved into massive excavators, such as draglines and bucket wheels, which rank among the largest machines ever built. Today, the United States and Germany, two of the most prolific strip-mining nations, lead the way in developing the technology for the machinery and infrastructure to facilitate these macroscale mining operations.

Strip mining occurs in numerous regions other than the United States and Germany. Resources are extracted by strip mining throughout Canada, India, China, Russia, Indonesia, South America, and Africa, among other locales. Energy resources such as coal and oil shale are often extracted through strip mining, as also other resources such as copper and iron ore. Strip-mining techniques are used worldwide for several reasons. Strip mining is highly economical because it requires far fewer workers than underground mining and because it generally is a shorter-term investment, [Page 2702]allowing mining companies to move more quickly onto other operations. Also, strip mining is safer for workers than underground mining because of the hazards associated with the latter, such as cave-ins, explosions, and respiratory problems such as black lung disease.

Traditionally, there have been two types of strip mining. The first is suited for flatter mine sites and is known as area stripping. This method places the extracted overburden from the strip currently being mined into the neighboring strip mined previously. The second version is termed contour stripping and is applied to areas that are hillier. Both methods are used in extracting coal, the mineral most associated with strip mining. For years, strip mining of coal in the United States was confined to the flatter areas of the Midwest and West, most notably the Powder River Basin of Wyoming. Mining companies in coal-rich Appalachia were not able to take advantage of the economical methods associated with strip mining until the development of a different type of strip mining called mountaintop removal.

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