SECRET SEARCH

Greymouth Evening Star, 3 August 1946, Page 4

SECRET SEARCH

URANIUM DEPOSITS

INVESTIGATIONS ON WEST COAST

RADIOACTIVE MINERALS *

Officers of the Department of Scientific and Industrial Re-

search, working under military control, and conditions of the

strictest secrecy, recently carried out a comprehensive survey of

the West Coast in an effort to lo-

cate supplies of radioactive minerals, as a source of supply of uranium, the basis of atomic energy.

Only those directly connected with the investigations were permitted to know the activities of the officers engaged on the search for the minerals. The work was largely confined to the concentrates obtained by the refining of gold from the alluvial dredges in the district, which previous investigation, prior to the announcement of the discovery of the atomic bomb, had shown to contain minute quantities of radioactive minerals, some closely related to uranium. These discoveries were largely of academic interest until the echoes of the Hiroshima atomic bomb overnight made uranium one of the most sought-after minerals in the world. Immediately, attention was focussed on the West Coast alluvials and the Government, working in close co-operation with Allied military authorities, took immediate steps to safeguard New Zealand’s potential supplies of uranium.

Work on Dredges. A party of scientists and geological surveyors, under Mr. D. S. Nicholson, of the Department of Scientific Research, shortly afterwards commenced investigations. They visited all of the gold dredges in the district and even erected jigs at some for the saving of the important concentrates. The actual amount of minerals recovered by the investigators is, of course, a closely kept secret, but, measured by common standards of weight, it was very minute, and its transport to the North Island for further investigation and analysis did not present any difficulties in regard to the maintenance of the policy of secrecy.

From the West Coast, the investigations have been transferred to the Thames School of Mines where the highly technical process of re i covening the soughtafter minerals from the concentrates obtained here is being carried out by Mr. Nicholson. present, work is confined to samples from the Ngahere dredge, as being typical of others in the area.

The existence of uranium in New Zealand has been known for some time, as it is a relatively common element, being about twenty-fifth in the order of frequency throughout the world. Its concentration, however, is very low, except in Canada and Belgian Congo, where the richest deposits lie. The substance is found in two main minerals on the West Coast — monozite and zircon. Its incidence in the former, rarely found itself, is about 1.15 per cent. From the dredge gravels and sands concentrations can be estimated, but figures for New Zealand have not been working out accurately. It is thought that the amount of uranium will be predictible in figures of decimal millions in relation to other substances before the exact quantity can be arrived at. Microscopic Quantities.

To assist in this work, the microscope plays a valuable part. Under it mineral crystals in oil solution assume colours and shapes which tell a different story. Monozite is a palish, flat green, while zircon assumes a translucent hyacinth, this being the mineral which is usually sold as the precious gem named after its colour. From dredge samples, traces of these minerals are likely to be flight, and each granule requires fairly' close observation in case it slips by. The mineral rocks themselves do not give uranium as such, but an oxide form which must be treated further for uranium. Although fair results might be obtained by research, economic costs in evolving the uranium itself might be an insuperable barrier. In view of the minute quantities of radioactive materials which, as they have known for some time, exist in the alluvial gravels, West Coast dredging men, although only laymen as far as atomic research is concerned, are not optimistic in regard to the economic possibilities of the new field of research. They are, however, awaiting with interest some official announcement as to the results of the recent investigations.