There are several methods for moving prepared coal from the mine face to the surface. In the early days of mining, the manual loading and transportation of coal can be done with Loading of coal into tubs. Now, we use SDL/LHD loading of coal & Belt conveyors for carrying coal over long distances. Side discharge loader (SDL) is one such machine that is designed to work in underground mines. They typically scoop coal from face and load runs into transportation types of equipment such as coal tubs, chains, or belt conveyors.