The Mechanical Handling and Storing of Material

ENDLESS ROPE AND CHAIN HAULAGE 257 got through a drift in the side of the mountains. In the older installation it was the practice when using rope haulage to convey the ordinary mining trucks to a raised position on the bank, and there transfer their contents into self-emptying trucks, which were then Fig. 372. Stops Built for Tubs Travelling in an Upward Direction. sible. The installation handles the taken by a second haulage installa- tion to the ore pockets for further treatment. It is obvious that this method could be much simplified by one haulage system, without transferring the load, by using the self-emptying trucks in the mine and conveying them in one opera- tion to the ore pockets. This has been done at Düdelingen, and the installation has been successfully at work since 1908. The mining authorities were rather reluctant to adopt this system, owing to the danger of any of the self-emptying trucks discharging their loads on the inclines underground, but the construction of the trucks makes such an accident almost impos- material in one unbroken operation from the face to the pockets, but there is a second haulage plant on similar lines, which takes the ore from the ore pockets to the blast furnace of the same company, a distance of 2J km., say 2 miles. The self-unloaders used are shown in Figs. 376 and 377, built on the Heckel principle. The capacity is about 2 tons of ore, and the weight of the trucks is nearly 1 ton. The wheels are of cast steel and fitted with roller bearings. The illustration explains the other details of construction. The opening of the side doors calls, however, for some little further description. The two doors are held closed by the catches and are opened by the lever Z», which, in order to release the catches 0, must make a downward movement (a similar catch with an upward move- ment might release the load by coming in contact with a piece of ore lying between the rails). The apparatus Fig. 373. Stop for Tubs Travelling in a Downward Direction. acts as follows : A pair of channel rails c are fixed in the centre of the track hinged at one end and raised at the other, but if not in use the raised portion can be lowered to bring it out of action. As soon as the truck approaches these channel rails c, a double pin in lever b engages with two channels and forces lever b down, which releases the doors. The ore pocket with its approach is shown in Fig. 378. This pocket is 330 ft. long, and has a capacity