Incoming material such as coal and raw ore are stored in large outdoor piles. The large quantities of material are essential to have on hand for production and may include several weeks of supply. How the material is transported into the area varies with the mine and can create different challenges. Material is often handled with conveyor belt systems that transport it into a large holding area. It could be deposited directly underneath a stationary stacker system into a large pile, or it could be spread over an area with the use of a radial stacker system.