Promising nodules found off Hokianga

Press, 17 January 1986, Page 20

Promising nodules found off Hokianga

PA Whangarei The seabed off the Hokianga Harbour could hold the key to saving New Zealand millions of dollars spent importing phosphate. Phosphate nodules have been found about 50 kilometres off the Northland coast and Spectrum Resources, a mining company, hopes to begin sampling the seabed within two months.

If the results are positive, New Zealand could see big savings on imports and the Hokianga Harbour economy would receive a boost. At present New Zealand spends about ?100 million a year on phosphate which is imported from Pacific islands such as Nauru. The New Zealand company discovered the information about the nodules from research by an Auckland master of science student. The company’s director, Mr Peter Roberts, said that an Oceanographic Institute ship on its way to the Three Kings Islands several years ago took a dredge sample from the Hokianga Plateau about 50 kilometres off the coast. Subsequent research by the student revealed that

the sample contained about 30 per cent phosphate nodules.

Mr Roberts said these nodules were about the same composition as those found on the Chatham Rise. He said Fletcher Challenge, and more recently a German consortium, had researched the Chatham Rise.

“I think about ?2 million was spent evaluating the Chatham Rise,” he said.

Mr Roberts said the Chatham Rise phosphate nodules were found to be useful because the phoshate could be crushed and directly applied to pasture. Imported phosphate had to be processed into superphosphate.

“It is slow release and can be applied every two years instead of every year with the present product. Imagine the savings in cost to the farmer,” he said. Other savings would result from the Hokianga resource being much closer to land than the Chatham Rise phosphate and also nearer to the area for its widest application, the central North Island. Mr Roberts said the sample indicated that the phosphate was between 300

and 500 metres below the sea floor. Mining would not be a great problem as overseas technology made mining down to 4500 metres feasible. “We will not know what the prospects are until we have done the sampling but we definitely think it is worth the chance,” he said. The company has sought a prospecting licence and because the area is offshore believes there will not be the same complications as in gaining a licence for a land-based operation.

Initially the company will dredge samples over a 500 square kilometre area about every two kilometres. Spectrum, formerly called Crusader Minerals, has three principals. Mr Roberts is a geologist with experience in New Zealand and overseas.

He said he had worked for the Australian Government as a minerals economist for three years. The other two men are Mr Mike Baker, with 20 years mining experience world wide, and Mr Dennis Kelly, a geologist and former secretary for the Brierley group.