Surface mining is a method of mining used to extract minerals and metals which are near the surface of the Earth. There are three basic types of surface mining: open pit mining, strip mining, and quarry mining. These methods are much more economical than underground mining, yet they can have a more significant impact on the surrounding environment unless efforts are taken to reclaim the land. Open pit mining involves excavation which looks like a terrace. Cuts are made into the ground, and the area at that depth is worked around the circumference of the mine. Once the minerals and waste have been removed from the ledge, called a bench, the excavation moves down a level and work begins again. This type of surface mining, also known as hard rock mining, is typically employed to extract metal ores, like copper, gold, iron, and aluminum, and other minerals. Strip mining is a form of surface mining that is primarily used for coal excavation. The rock and dirt covering the ore is removed one strip at a time. Once the ore has been taken from the first strip, a second strip is cut next to it, and the waste from the second strip is used to back fill the first. This goes on until the ore is exhausted, and then the waste from the first strip is used to fill in the last.