Oceanic Portland Cement Company.

Progress, Volume VI, Issue 5, 1 March 1911, Page 573

Oceanic Portland Cement Company.

Limestone Mountain. Possibilities of a Great Industry. Portland cement may be made from a great variety of materials with equally satisfactory product, but by far the best combination of materials is the mixture of what is known as "cement rock'' with crystalline or "white" limestone. . These materials must contain lime, silica, alumina and iron oxide in certain narrowly defined proportions and must be free from any considerable quantities of such deleterious ingredients as magnesia and sulphur. The cement rock of Limestone Mountain (western edge of Whangarei Harbour), and the white limestone outcropping at its base show a composition unrivalled by any other known deposits of similar materials in any part of the world. The third necessary raw material of great importance is the coal. There are very strong indications that coal will be found underneath this property, but if such is not the ease the suitability and proximity of the coal from the adjacent fields of Whangarei and Hikurangi insure a good supply at a reasonable cost. This is the famous "Limestone Mountain." It covers about 500 acres, and contains not less than 500,000,000 tons of stone: enough to furnish all the Portland cement works in the world with stone for the next fifteen years at the present rate of manufacture, or New Zealand for the next 4000 years. The above stupendous figures at once set at rest any possible doubts as to the quantity of the deposit, while the quality is assured by comparison of its analysis, not only with those of similar stones in use in other parts of the world, but with analyses of the stone used in producing a high grade cement at the adjacent Limestone Island works.

The natural advantages of this wonderful deposit are: —The practically unlimited supply; unsurpassed quality of the stone; presence of both stones on the property reducing the cost of production below that of existing works in New Zealand; proximity of coal supplies; railway with three miles; 15ft. water alongside at low tide; a good supply of water; within reasonable distance of an almost certain future supply of cheap electric current; an excellent site for the works, with room for any possible future extensions. The, artificial advantages of the place must, of course, depend upon the erection of very large works and markets. The consumption of cement in New Zealand for 1905 was 60,000 tons, and for the present year will reach the amount of 100,000 tons. Assuming that this rate of increase holds good, the quantitv of cement used in 1915 would be 170,000 tons. But, as a matter of fact, the rate of increase is itself increasing so that there is little doubt that the amount of cement used in New Zealand will reach 250 000 tons in 1915. Further than this, if the selling price of cement can be reduced by a few shillings per ton export markets will be opened u- which will enable the New Zealand product to enter the markets in Australia, the Philippine Islands, the entire west • coast of South America, and perhaps even the western coast cities of the [Tinted States. In Professor James Park's book on "The Geology of New Zealand" (1910) the following statement appears: '•Concrete is the coming building material of the future; and New Zealand, with its enormous deposits of limestone and clays in juxtaposition, its waterpower and coals, its long seaboard and deep harbours is destined to become the centre of cement manufacture for the South Pacific.