Waterjet mining. Worker observing a waterjet cutter cutting out blocks of sandstone in a quarry. The cutting mechanism is mounted on rails (lower centre) allowing horizontal movement. The runner (at right) allows vertical movement. These cutters use jets of water mixed with abrasives (such as silica sand or garnet). The water is compressed in a reservoir and when it is released it enters a chamber where it is mixed with the abrasives. It will then exit the nozzle at a pressure 1200 times that of atmospheric pressure. These cutters can cut 3 cubic metres of sandstone per hour with high precision. Photographed at Carriere de Rothbach, Alsace, France.