A POWERFUL TIN DREDGE.

Otago Witness, Issue 2762, 20 February 1907, Page 27

A POWERFUL TIN DREDGE.

An exceptionally large and powerful dredge is now under construction for the Dorset Bucket Dredging Company (Tasmania). In some respects it is tbe largest and mest powerful dredge- yet designed in these- colonies for mining purposes^ The hull, in which is embodied a littlo over 200,000 ft of bluegum and stringy bark, is 125 ft long, 37ft wide forward, 48ft wide aft, Bft deep forward, and 9ft Sin deep aft. The tin-saving tables are interesting. They comprise 3000 square feet, and are capable of carrying over 200 tons of material. To balance this weight special ballast tanks have been provided aft to secure even flotation. The machinery is very heavy, all the ge-ar being of cast steel imported from Sheffield., The driving power is supplied by two 25 horsepower Marshall engines^ — one engine driving the buckets and the other the centrifugal pumps. One- pump, 6in centrifugal, supplies water through a number of nozzles at a pressure to break up refractory wash, trie other pump, 17in centrifugal, supplies the bulk water for washing. The water is under the direct command of the boxman, and can be j shut off at any part of the tables at pleasure, j The caiJacity of the buckets is a little ovex ! six cubic feet, and they run 12 buckets per minute, so that the dredge can lift about 350 ft tons daily. The ladder is 66ft long between the centres, and can dredge to 30ft. j Mr F. W. Payne, of Dunedin, is the consult- j ing engineer to the company. The bulk of the , machinery has been constructed by the Austral | Otis Company, under the supervision of Mr E. M'Ldntock (late of Dunedin). and 19 now being tiiipjped to Port Boobyalla, which is within 15 miles of the claim. Mr Payne haa just returned from a visit of inspection to the pontoons and machinery, and estimates that the dredge -will be ready by the end of April. The pontoons are almost ready for launching, and they are being cau'iked and tarred under the supervision of Mr John Gordon, of Alexandra South, who will wait the arrival of and fit in the machinery.