258 MODERN PAPER-MAKING
Handling of Raw Materials.—RAW materials for newsprint are required in
large quantities, and therefore up-to-date methods of handling and transporting
are an essential part of a modern mill. It is of prime importance that the site
should have good rail and water transport facilities; and, in addition, road
transport is essential, as it is used almost exclusively for the distribution of paper
to customers in this country. It is also used for conveying general stores,
machinery and the less bulky raw materials, such as dyestuffs, to the mill.
A well-located newsprint mill, producing, for example, 3000 tons of paper
per si-day week from four modern machines, will consume approximately
4500 tons of moist mechanical pulp, 500 tons of air-dry sulphite pulp, 300
tons of china clay, and 2000 tons of coal per week, all of which will be
delivered by ships carrying anything from rooo to 5000 tons or more
of cargo. These ships come alongside the mill wharf for unloading. Coal
and china clay are grabbed out by the wharf cranes and discharged direct into
the bunkers provided. Pulp is lifted from the ship's hold, usually four or five
bales at a time, on to trucks belonging to the mill, and the bales are tidily stacked
subsequently, using gantry cranes.
Coal is conveyed into the mill continuously by bucket or belt conveyors,
and clay is usually slurried in a building integral with the clay bunker, the slurry
being then available for pumping to the point at which it is mixed with the
stock in the mill. Pulp is reclaimed from the stacks by the mill gantry cranes
and taken to the beater floor, either by electric trucks or in some cases direct
by crane.
The handling of newsprint raw materials has been specially mentioned in
order to emphasise the important point that with only a relatively small
.margin between raw material costs and the selling price of the finished product,
conversion costs, which of course include the cost of handling materials,
must be kept to the most economical level possible. Newsprint to-day is
essentially a cheap product, mass-produced in enormous tonnages. Every
effort must, therefore, be made to ensure that labour is not wasted by inefficient
methods of handling materials.
Jitter.—The water supply for processing the paper is obtained usually from
wells, although in some cases it is drawn from rivers. River water often re-
quires rather elaborate flocculation and filtration treatment, but well water has
the advantage that it rarely needs any treatment at all. The quantity required
for all paper-^iiaking purposes will be of the order of 12,000 gallons per hour
per machine, wliidi, at 6 tons per hour production per machine, is 2000 gallons
of water per to& of paper manufactured. Of this quantity the dryers will
evaporate about 2500 gallons per hour, the remainder being necessary to make
up mddmtal noarHtecoverable losses, such as hosing floors, machine wash-ups,