MILLING

At the mill, the ore received from the tramline normally requires
drying in rotary kilns to reduce moisture to a level suitable for milling.
After drying, it is delivered to the dry rock storage building. From this
building, dried ore is drawn as required by a conveyor in a tunnel be-
neath the storage piles to the head of the mill.

The actual process of separating the fibre from the serpentine
rock now commences. This process is based on the fact that, as the
fibre is crushed and handled, it gradually expands or fluffs up so that
it becomes lighter than the rock from which it is to be separated. The
mill feed is passed over horizontally gyrating screens, during which
time the fibre tends to float on the surface. Because of its effective low
density, it is possible to separate it, or draw it off by means of air suc-
tion, or aspiration, in the manner of a vacuum cleaner. The rock is
further crushed to free additional fibres. These fibres are carried by air
through ducts to cyclone collectors and then over a series of gyrating or
rotary screens which clean and grade the fibre. Exhauster fans handle
~ over 300,000 cubic feet of air per minute in this aspiration process.

A Wheelabrator dust collecting system filters the air for recircula-
tion through the mill. This makes it possible to maintain comfortable
temperatures in the mill during severe winter periods as well as provide
conditions necessary for suitable hygiene.

Tailings consisting chiefly of minus 1/8” material are stacked by
two conveyor systems which are equipped with high speed flingers at
their discharge. The flingers throw tailings in a 40 foot radius to build
up two large piles. Short fibre lost in tailings is not economically re-
coverable in an area so remote from markets.

After the fibre has been cleaned of all the rock and dust and separ-
ated into grades of different fibre lengths, it is collected into bins ready
_ for bagging. Each bag when filled contains 100 Ibs. of compressed fibre
and is appropriately printed and colour coded for identification. The
bags are stacked on pallets in lots of 20 and carried by fork lift trucks
to the fibre storage building. Here the one ton units are automatically
compressed to a uniform size and strapped for shipment. A fleet of
company owned semi-trailer vans transport the fibre to Whitehorse
where it is transferred by rail to Skagway and by boat to Vancouver.
_The fibre is stored in large company warehouses in Vancouver for ship-
ment throughout the world.