Trucks Tramline A prime example of this is the hydraulic pressure packing system. Faced with continuous electrical prob- lems from the electrical control system and leaks and failures from the hydraulic piping, Cassiar staff re- designed and simplified the electrical circuit and had a solid manifold built for the hydraulic circuit on which are mounted all the control solenoids (Fig. 3). This type of change, together with the use of new lining materials in heavy wear points, different types of belts, etc., is beginning to result in very noticeable improvements in the operation. Power Plant One of the important parts of Cassiar’s operation is its powerplant. Without it we would have no electricity or steam heat in the plant, the mine or the townsite. The powerplant started in 1952 as a small log cabin housing two small diesel generators of 50-kw capacity. By the mid 60’s, the plant had grown to an 80-ft (24.4-m) by 82-ft (25-m) Butler building housing eight 2300-volt diesel generators with a total capacity of 3673 kw. Power was then distributed to the mill, plant and townsite via four 2300-volt feeders. The mining shovels and drills, being either diesel powered or having separate diesel generators, were not con- nected to the powerplant system. There was, however, FIGURE 5 — 1400-kw generator in the powerhouse. Shovels a 13.8-kv overhead line with step-up and step-down transformers to supply mine auxiliary power and the crushing plant. Ten years later, the power consumption at the site has risen from 1964’s output of 14 x 10° kw hours to the present 43.3 x 10° kw hours, with a projected in- crease of 12.9 x 10° kw hours/year due to a new plant in 1978. To keep up with this, the size of the diesel generating units has had to be changed and an extra bay added to the building. There are now nine units installed, with a total rated capacity of 11,672 kw. Only one of these dates back to 1964. (Table 1 and Fig. 4.) All units generate at 2300 volts and feed onto an ITE switchboard, with feeders supplying the mine, mill, townsite and powerplant auxiliaries. It is a simple statement to say that additional en- gines have been installed to cope with a threefold in- crease in power. However, many other changes have had to be made to cope with the increased installations. A new control room, new crane and lube systems have been installed over the past 18 months. Within the next few months, a new engine cooling system will be commissioned, using forced-draught cooling towers in a closed-loop system. The present system, one that has been in use for many years with little change, is open ended. Cooling water is pumped from a nearby FIGURE 6 — Main 2300-volt switchboard in the new control room. 450 ae en a Ne ee ee ee