The Mechanical Handling and Storing of Material

664 THE MECHANICAL HANDLING OF MATERIAL are provided with slides which may be opened or closed forjthe purpose of filling either the upper or lower bins. The same spouts also serve to ventilate the lower bins. Coal brought by rail or by wagon is carried by subterranean shoots provided with cut off valves to the lower strand of the gravity bucket conveyor. To lessen the danger of combustion it is perhaps above all things necessary to keep the height of the layer within certain limits, but another excellent means of combating this risk is to provide means of turning over the coal and clearing the bins whenever desirable. The contents of the upper bins are discharged into railway trucks or carts and wagons by means of slides and shoots which are provided with valves, while the lower bins are discharged by a gravity bucket conveyor either direct or via the upper bins. For turning over the coal from the upper to the lower bins the slides communicating with the two may be used. The turning over, however, must not be repeated too often, on account of the breakage caused to the coal. Fig. 940. Ore-handling Plant of the Wheeling and Lake Erie Railroad, Huron. The temperature of the bins is exactly recorded from time to time by thermometers, which give the maximum temperature, the former being enclosed in iron pipes which descend into the coal. The low cost at which the handling of the coal may be effected is, of course, the most essential feature in this system of storage. Another important point in this installation, in which it differs from any of its predecessors (including the 30,000 ton store of the Danish Coal Co., of Copenhagen), is its accessibility from all sides. Except for the necessary gangways, which of course take up a little room, the whole of the stores have been utilised for storage purposes. When the upper bins have been cleared they may gradually be filled from the lower, and this operation, carried out at a minimum of expense, has the undoubted advantage of aerating and cooling the coal. The Mechanically Equipped Ore Pile, as in use by the Wheeling and Lake Erie Railroad. Huron, Ohio, is illustrated in Fig. 940, which shows four stacking machines. They are built by the Wellman Seaver-Morgan Co., are rope operated and