Sluicing in California.

Cromwell Argus, Volume 2, Issue 79, 16 May 1871, Page 7

Sluicing in California.

" Hydraulics mining," or sluicing, is the great feature in the operations carried on in the auriferous districts of California. Sluicing is there carried on on a gigantic scale, there being usually a plentiful supply of Water, which is our great want in the New Zealand gold-fields. The Californian miners are constantly on the quiyhe for improved appliances;. arul v in a i-ecent number'of the "Saul Francisco Bulletin" an account is given of Some new inventions. The last year (says the paper above referred to) has been signalised by the introduction into Californian mining of im* provements which must give new life to the business, and add million's -to our annual yield of gold. Chief among these are the hydraulic nozfcles, which, while reducing the expenses, more than double the working power of the hydraulic claims. Of these nozzles there are three varieties now in use—viz., Craig's "Monitor," Fisher's "Knuckle-Joint," and Haskin's "Improved Nozzle." All three, though by different devices, accomplish the same end—that of dispensing entirely with the Use of hose by the attachiug of a moveable and easily managed nozzle directly to the iron waterpipe, thus making it possible to direct against a bank a stream of as great volume and pressure as iron pipes can be made to carry without bursting. In California—,i(as in New Zealand at present)—when hydraulic mining first commenced, canvas hose was used to convey the water from the ditches into the claims and to the points from whence it was to be hurled, by the force of the fall, against the banks. Though made in the most careful manner, and of the strongest sail-cloth, such hose could not bear the pressure of a fall or head of more than eighty or a hundred feet, and is moreover constantly rotting and giving way. The Vapid Wearing of the canvas hose, as well as the necessity for using larger streams and greater force to move the firmly compacted dirt and gravel, finally led, in all large claims, to the substitution of sheet-iron piping to. bring (jthe water from the supply ditches (or water races) into the claims. Thus a great increase of the volume vnd force ot the water carried was made possible. But the increase in the power and volume of the streams used was still limited by the inability to direct them by the hand, and the necessity of having a flexible dis-charge-piece connecting the pipe with the nozzle, and permitting the latter to be moved as occasion required. However, by making the discharge-piece of Stout canvas, covered with a network of matting or strong rope, the size and powei' of the streams used, and consequently their efficiency, was largely increased. But still the desideratum of an easily-managed stream as powerful as iron pipes Could carry was not secured until the study of the problem by our miners gave birth to the inventions we have alluded to, arid which are already in general Use. These new hydraulic nozzles are attached directly to the iron pipe, and by a simple but ingenius contrivance, are given both a lateral and perpendicular motion, which can easily be directed by one man. Instead of two hundred and fifty inches of water with a head of from one hundred and fifty feet, twelve hundred inches of water, with a head of three hundred feet, can how be driven against a bank in a single stream. The saving thus ofl'ected is enormous. It is not only that the water formerly sent through seven or eight ordinary hose pipes, each requiring from one to three men, can now be managed by a single hand; but its efficiency is greatly increased. Closely compacted gravel and hard cement, which water, as formerly used, Could not move, and which required the pick Or the blast, are easily disintegrated and washed away by the tremendous force of the gigantic streams now used. These inventions, too, save human life, as well as human labour. Formerly, the pipe-holdars had to stand so close to the banks that they were frequently crushed by the toppling over or caving of immense masses of earth. But with the powerful streams now coming into use they can remain at a safe distance, and yet do more execution. How is it that steps are not taken by the Government, or by mining companies, or private individuals, to introduce iron pipes and "hydraulic hozzles" into New Zealand ? It is evident that they would be a vast improvement upon the present rude canvas hose ; and, by saving both time and expense, be in the long run far more economical.