Vast Possibilities For Northland Clay Deposits

Northern Advocate, 30 August 1947, Page 8

Vast Possibilities For Northland Clay Deposits

EXPERT PREDICTS

THE vast possibilities of expansion in the utilisation of Northland’s bounteous clay resources were discussed by Mr D. C. Stewart, an Auckland pottery expert, or ceramist, in an interview at Whangarei this morning.

He is the managing dif’ector of an Auckland firm, Spartan Products, Ltd., which is utilising a number of Northland clays for the manufacture of a great variety of pottery articles, including such products as vases, tiles, insulators, refractory elements for stoves and heaters, miniature statues and ornaments.

part in the alleviation of the housing shortage.

While his firm,' owing to the present specialised nature of its work., was not intending to launch out into this field, Mr Stewart said that the ex-iene-j and the knowledge of his team of experts would be available to any local company which might consider such an undertaking. The great demand for house-build-ing bricks and the more than adequate supply of raw materials would ensure the economical operation of suen works providing the right methods and equipment were used. THREE BASIC TYPES Commenting on the three basic types of clay, needed for a variety ot pottery purposes, he said kaolin, a clay noted for its toughness, was found in large quantities at I’uhipuhi. while the plastic clay, valuable for its bonding properties, was available from Kiripnka and Kerikeri.

Northland contained millions upon millions of tons of valuable highquality clays of various types, sufficient to maintain huge pottery and brick-making industries for generations.

HARDLY TOUCHED » At present these resources had been hardly scratched, but he visualised the time when Northland, by virtue of its rich and plentiful deposits of raw materials, would become the major industrial province in the Dominion. Speaking of the brick-making industry. Mr Stewart said that extensive tests had proved that a fire brick second to none in Australia or New Zealand could be produced from a mixture of Kamo and Kiripaka fire clays.

Silicious clay necessary where expansion and contraction would be encountered. was found at Kaoo. One of the virtues of Northland clays used yj pottery-making was that they were nearly white in colour and contained few impurities. The main impurity was iron, which was removed ■by electro-magnets after grinding. Another point in their favour was their fineness. Consequently less grinding was involved. They could be used for the manufacture of goodquality chinaware such as cups and saucers, but in this case a small amount of felspar clay from the South Island would be a necessary ingredient.

In the Kiripaka district there were at least 1,000,000 tons of fire clay which, according to an analyst’s report, was so near in quality to the English fire clay—considered to be the best in the world—that the difference was of no importance.

The Kamo fire clay, also of a very high quality, was found in huge quantities between the seams of coal. FOR HOUSEBUILDING For housebuilding a vast amount of red clay was to be found in Northland .no in this respect there was ample seepe for the development of at least six brickworks between Warkworth and Kerikeri. Small works with modern plant, including tunnel kilns, could provide sufficient common bricks to play a big

His firm had 'carried out a great number of tests and experiments with different combinations of Northland clays and had tried out many processes resulting in varied and highgrade products.