The New Student's Reference Work/Steam-Shovel and Dredge

Steam-Shovel and Dredge, a machine, worked with crane and steam-power attached, mounted on wheels for running on rails, and used for excavating clay, sand, gravel or other soil in railroad or other cuttings; also used for river-dredging, the deepening of canals etc. by a suction-process. The steam-shovel in use for heavy work has a boom, usually made of strong steel-girders, with a powerful thrusting-engine for giving ample scooping-force to the shovel, the latter generally being provided with heavy, pointed teeth for excavating loose rock. The bottom of the shovel or bucket is hinged, so that, when filled and raised, its contents are released by pulling a latch-cord and dumping the load into cart, car or other vehicle for removal. The thrusting of the shovel, as well as the hoisting and dumping, is the work of the attached engine, working along the movable crane. With a 2½ or 3 cubic-yards' shovel about 2,400 cubic yards of sand and 600 of loose rock can be excavated in ten hours. For dredging river-bottoms and delivering the mud or other material on shore, machines with belt-conveyors are used, different in pattern and varying in capacity and rapidity in work. Some varieties deliver to the shore or to a scow alongside by gravity, by means of an extensible sheet-iron trough or sipper-shovel of large dimensions.