Prospector builds dredge

Press, 7 December 1978, Page 26

Prospector builds dredge

PA Dunedin A dredge to be used for excavating gold from Otago rivers is nearing completion in a Dunedin engineering workshop. The dredge is a miniature version of the big gold dredges that worked the main rivers in the province a century ago. It is being built by a

former radio journalist and tour manager, Brian

Jackson. Mr Jackson, aged 31, designed and built the $4500 machine himself. He said that he had spent last summer in Central Otago prospecting for gold. "I built up a knowledge of where the gold was and in what quantity,” he said.

Me had “no difficulty’’ in finding a show of gold virtually wherever he went.

He began to think of a design for a small, oneman dredge to exploit his prospecting finds. “The machine will give me an income and will also be a pilot plant, which is its major function, to determine the value of gold per cubic metre of whatever stream or river I’m working in,” he said.

The dredge looks like a smaller version of the oldtime bucket dredge. It has 60 buckets on a chain along its digging area, each with a 900 cu cm capacity. The dredge can dig and process a capacity of 3 cu m of sand or gravel an hour and the bucket arm can reach a depth of a little under 2m. The dredge floats on

two pontoons and is run by one man sitting at the back of the bucket arm. It is powered by two motors giving about llkW and has a pump capable of pumping 1400 litres a minute. As the material dredged by the buckets passes along the arm it falls into a chute, is washed, and flows out onto a conventional riffle boy underneath the operators seal, where the gold is screened out. The dredge is moved about by ordinary yacht winches. While it is running it is held in position by two “spuds”: arms at the rear which are driven into the ground.

Mr Jackson said the dredge would be ready to start on its Central Otago location within two months.