The Whakatane Board Mill

Te Ao Hou, Winter 1952, Page 12

The Whakatane Board Mill The mill started operations in July, 1939, a few weeks before the beginning of the war. By this time seedlings planted out in the company's 46,000-acre plantations in 1928 were ready for manufacturing processes. During the war the plant produced an average of over 11,000 tons of cardboard per annum, which was in excess of New Zealand's pre-war consumption. At present production stands somewhere around 15,000 tons per annum. The rather specialized machinery used is Swedish. The exact processes through which the pulp passes on its way to the cardboard stage are rather complicated to describe, but roughly the treatment is as follows. Cardboard consists of three main pulp constituents, namely the pulp ground from the freshly cut trees, imported chemical pulp and waste paper. A common furnish for a good strong cardboard used extensively today is approximately 30% waste paper, 50% ground wood, and 20% imported chemical pulp. In addition the production of card-

Bill Walker, foreman of the beater room, has Pakehas as well as Maoris working for him. The chemicals and other constituents are mixed together. The mixture determines the quality of the board. board requires an enormous water supply. The Whakatane mills take 3,000,000 gallons daily from the Whakatane River. The pine trees are cut into 3 feet bolts, debarked and then fed into the grinders. These machines consist essentially of a large revolving carborundum stone against which the logs are forced under pressure in the presence of a stream of water. As the stone grinds the pulp from the log the stream of water carries it away. Exceptionally big motors, 1200 h.p. each, are required to drive each grinder. The groundwood pulp, which now has the appearance of porridge, is subsequently passed through screens and refiners prior to being pumped to the beater department. Here the mixture is made which decides the quality and properties of the board. Apart from the main constituents described above, various chemicals are introduced: rosin and alum for sizing and to prevent the penetration of moisture, starch for hardening and stiffening, clay for loading, wax emulsions for water proofing, and dye for colouring. After further refinement the mixture passes to the board machine. The fibres in the wood are now entirely disentangled. In the board machine the fibres are piled together, pressed and dried to form the final sheet.