SULPHUR DEAL: 'MAJOR STEP' TAKEN

Taupo Times, Volume 23, Issue 50, 25 June 1974, Page 1

SULPHUR DEAL: 'MAJOR STEP' TAKEN

The experimental sulphur extraction programme at Lake Rotokawa has been taken a "major step" forward with the delivery of the first loads of molten sulphur to the Napier fertiliser works.

Two 12-ton loads have been transported by road to the East Coast Farmers' Fertiliser Company. The most recent delivery was made last Wednesday. "The molten sulphur was converted into sulphuric acid within hours of its arrival and the fertiliser company said there had been no problems, said the chairman of the Fletcher Mining and Exploration Company, Dr J. S. Watt. "Although we are still very much in the development stage, this has been a major step forward." The sulphur project began in 1971 as a joint venture between Fletcher Mining and Gulf Resources and Chemical Corp., an American company experienced in sulphur extraction using the Frasch process. About a year ago, when the project reached its second stage of development, Fletchers agreed' to finance the programme in return for an increased holding in the venture. This is now 70 per cent. "The current work at Lake Rotokawa has been to modify and refine the well design and operating techniques, said Dr Watt. "We are now " placing wells in clusters in which additional mudding wells are interspersed." The mudding technique is designed to make the silt deposits that overlay the sulphur beds less porous. When hot water is pumped down under pressure, the mudding confines the sulphur close to the bore holes and a molten sulphur pool is produced at the base. "These tests have produced some sulphur but because of the experimental nature, production is still relatively low," said Dr Watt. "Our efforts are nojv

concentrated on increasing the production and we will continue to make deliveries to the East Coast Fertiliser Company as molten sulphur is produced." The molten sulphur from the wells discharges into a 35-ton capacity holding tank which is fitted with heating coils and a sulphur pump loaned by the fertiliser company. Kept molten by the coils, which also use geothermal hot water, the sulphur is pumped into a lagged tanker for the four-hour trip to Napier. The drop in temperature has been small and the sulphur has been delivered well above its melting point. Freightways Bulk Services Ltd., which supplied the original tanker, is now building a larger tanker for sulphur delivery.