WOLD DREDGING APPLIANCES. , Miners have now a multiplicity of machines

Otago Witness, Issue 1933, 7 December 1888, Page 8 (Supplement)

WOLD DREDGING APPLIANCES. , Miners have now a multiplicity of machines

from which to make a selection. By the last English mail particulars have been received of yet another dredge doing successful work in France, at Lyons and Havre. This dredge is, however, only a fac-simile of Robertson's dredge, recently introduced into New South Wales. A description of this dredge, a working model ol which was lately exhibited at A. and T. Burts',

>vas given in the Times of 27th October last.

Ifc is, after all, the common hydraulic elevator, with the addition of an annular air chamber giving increased force and power to the jet of

w.ter. The hdyraulic elevator or ejector is one

I of the oldest forms of dredging known, and was | :totually used by the Carthaginians 3000 years I pgo. Mr Ekberg, an engineer on the West ; Coast, was, however, the first in New Zealand to demonstrate the working of the hydraulic ejector by means of steam power. There is no reaeon why steam power bhould not be used, and bo as good aud cheap a motivo power in many districts aod under certain circumstances as water power. Mr Ekberg lately drew attention toandillusfcrated thecomplete feasibility of working all alluvial deposits, except in the actual bed of larg.n-ivers,by thehydraulicelevator. Working on a dry bottom has an immense advantage over all dredging under water, as no gold can possibly be lost. It appears to have been taken for rranted that beach claims and inland flats ete«ped in water, such as the Dunstan and Waipori flats, can only be wrought by expensive dredging Jplant erercted on a pontoon. Never >vas there a greater mistake. Professor Ulrich cor.ld tell the miners of Otago that ground much deeper and with a much greater flow of water than any ground here has been successfully wrought in Victoria. Even at Waikaia the other day a flat which has always been believed to be unworkable for water has been successfully tackled. The depth to the washdirfc is 23ft, the flow of water 6000 gal per hour, and tho pump, which is but a small one, can lift 23,000 gal her hour. It seems quite clear from this that the sea beaches and water-logged flats of Otago can be wrought much more easily and satisfactorily than has been hitherto thought possible, and without the long delay and heavy expenditure necessary for working the bed of the Molyneux and other largo rivers.