The Mechanical Handling and Storing of Material

THE MECHANICAL HANDLING OF MATERIAL PICKING BELTS OR TABLES WITH OR WITHOUT LOWERING ENDS Picking belts or tables are used for removing stones and other impurities from coal Figs. 130 and 131. and other minerals. They have also a place in cement works, where they are used for the purpose of picking the clinkers over. Picking belts or tables in the form of ordinary band or Fig. 132. Cross Section of Wooden Slat Conveyor. steel plate conveyors have been described in the foregoing pages, so that it is not necessary to describe their construc- tion ; but it may be useful to set forth the manner in which these appliances and their accessories are used. In width, picking belts may vary from 3 to 5 ft.; 4 ft. 6 in. will be found a very suitable width if picking is to be done from both sides. A great diversity of material is used for picking belts : but canvas, india-rubber, or woven wire is seldom used, at least not for the heavy work of dealing with South Wales and other large coal, where a hard surface is absolutely essen- tial as well as substantial framework and carrying arrangements. A very important matter is the discharge of the coal from the belt. If a fall of any depth is permitted, breakage results, and to some extent the result of the previous