OCR

Belting: The belting, which has no fabric carcass, uses wire rope only for reinforcement. These steel corns run in the length-wise direction only. The belt has a soft rubber abrasion resistant top cover, followed by an upper intermediate layer of wear and tear resistant synthetic rubber. The center section is a highly tear resistant synthetic rubber, which is bonded to the steel cords. The construction is symmetrical about the center line. There are several important features of this type of belting: 1. Crosswise strength is obtained from the laminated effect of the different types of rubber. This construction provides adequate strength for normal forces across the belt, and since the material is rubber, the belt has a very large degree of elongation or cushioning when subjected to severe impact loading. 2. The steel cords permit a working tension of 1876 lb per inch of width, and an ultimate strength of approximately eight times this value. This high strength without loss of flexibility makes it possible to maximize the length of the conveyor without prohibitive pulley diameters. The main conveyors (maximum length 2300 ft) have pulley diameters as follows: Drive pulley 49-1/4 in. Discharge pulley 39-9/16 in. Tune-up pulley 32-9/16 in. Snub pulley 25-13/16 in. The high degree of flexibility in the crosswise direction facilitates troughing, as at transfer points where the troughing is 50°. This type of troughing centrally positions the ore for its long descent. 3. Symmetrical construction of this fabricless steel cord belting makes it possible and practical to turn the belt over after wear has progressed through the top cover. It is also possible to retread the belt at the factory after both wear covers have been expended. 4. High strength of the bond, between steel cords and rubber, simpli- fies splicing. At a splice, tensile strength is transmitted in part through the cables, and in part through the bond between cables and rubber. In other words, there is no mechanical connection of cable ends. By staggering and overlapping the loose ends of cable at the splice, the number of rope ends appearing in any 15-3/4 in. section of the splice is only 25 percent. Drive Components: The conveyors as now installed have two pulley drives , and one of the drive pulleys has a double extended shaft. The second extension will accommodate the addition of another complete drive unit for