b * “sm © taal — Ae 5
FIGURE 2—The tramline system at Cassiar.

system from the normal drive. The high torque capab-
ilities of this system have overcome start-up problems
and the infinitely variable speed between 0 and 180
fpm (forward or reverse) has cut greasing time from
16 hours to 8.

Loading

The tramline loading is fully automatic (Fig. 3).
Ore is transported from the crushing plant by conveyor
and fed into a 100-ton-capacity bin. The bin is heated
to prevent freezing of the ore, and kept empty to avoid
freezing whenever the tramline is shut down. From
the bin apron, feeders feed two counter-weighted air-
operated 40-cu.-ft (1.12-m*) loading hoppers. The
feeder is interlocked so that the apron feeder is shut
off when the hopper reaches a pre-set weight.

TABLE 2 — Financial Comparison of Delivery Systems

Case 1 2 3 4

1,200,000 | 1,200,000
900,000 1,200,000

T. Line A | T. Line B
(Riblet) | (Interstate)

Unit Cost ($) 1.38 0.79 0.44 0.31
Cost per Year ($) 1,242,000 | 948,000 | 528,000 372,000
Savings per Year ($) 294,000 | 714,000 870,000
After-Tax Savings ($) 176,000 | 458,000 552,000
Capital Required ($) 3,223,000 | 3,973,000 | 4,313,000
Ratio — Capital Exp.
to Income
after Tax
Rate of Yield — %

Mine Rate Per Year
Delivery Rate Per Year

Method i

1,200,000
1,200,000

1,200,000
1,200,000

Present | Trucks

*Costs in 1973 ($)

RX

ANOWSE

os

Siac

Eth

Sey

As the car comes into the loading area, it passes
an infra-red photo cell which activates a timer set to
open the loader hopper as the car passes below. The
control system allows loading to be done automatically
from either one or both hoppers alternately or man-
ually.

A system of belts below the loading area removes
any spillage.

Cars

The 142, 40-cu.-ft (1.12-m*) tramears are each
mounted on two axles, with a two-wheel bogie at each
end (Fig. 4). The initial wheels were a mixture of cast
and fabricated units mounted on roller bearings. Below
each truck are two brackets for attachment of the
214-in. open socket fitted to each end of the 214-ft
(65.2-m) long, 214-in. (6x25 Langs lay) haulage rope.
The socket is attached below the car with a steel pin
through a bushing.

The first modification made to the cars was the
addition of a three-piece 14-in.-thick polyethylene lin-
ing to help prevent the ore sticking during the altern-
ately freezing and thawing weather conditions. This
sticking has been further alleviated by installing a
four-nozzle automatic blowpipe at the discharge ter-
minal. The combination of these two have been effect-
ive and have reduced spillage of ore from the cars.

After only a short period of running, the pins hold-
ing the haul-rope sockets to the cars were found to
be spalling badly, preventing free movement of the
socket. Several different designs of pin were used, but
the only effective method of stopping the problem was
to grease the pins at three-week intervals. Cassiar
has recently modified a few tramcars and fitted bear-
ings for the pin to rotate in; however, at this time we
cannot say whether this will be successful.

A third area of modification on the tramcars is the

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