Open pit mining is also another form of surface mining that resembles 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.