RAISING WATER FROM RIVERS FOR GENERAL SLUICING.

Grey River Argus, Volume X, Issue 817, 10 March 1871, Page 2

RAISING WATER FROM RIVERS FOR GENERAL SLUICING.

Quite recently the attention of the mining community has been publicly called to a simple contrivance for economising the current of large rivers for goldsluicing, town supplies, and mill power, which is said to have been invented by Mr J. T. Thompson, Chief Surveyor of the Otago Province ; but the honor of the invention has since been claimed by several persons on the West Coast. However that may be, it is well worthy of the consideration of the miners in this district. The following is a description of it, as read by Mr Thompson, at a recent meeting of the Otago Institute : —

" Some years ago I inspected two machines, one of which was for the purpose of raising water, and the other for working the gearing of a dredge, and in both cases the principle adopted was that of the paddle wheel, though one was of unusual construction, being set obliquely to the stream. Neither machine had great power, and having become disused, appears not to have met the expectations ot their designers. The paddle wheel of proper and peculiar form, is no doubt well adapted for driving the machinery of floating mills (flour, bone, saw, &c.) in shallow rivers, where shallowness of the stream would prevent the screw being applicable, and where there was large floatage capacity, at any rate, required to support the mill and its contents ; but its great size, cost, and weight of the paddle form of wheel create a most important objection to its general use in the Clutha, where only the temporary works of gold rninuig for the most part are engaged in. Ifp^the contrary, the great depth of the stream is particularly applicable to the screw, working as it does so much below the surface, anjd when its smallness and lightness make it so easily handled, and its cheapness and simplicity render it of easy construction and repair.

" The floating paddle wheel in a seven mile current requires 40 square feet of float board to give a power of 12 horses, and of float boards there requires to be eleven in number; while one screw of eight feet diameter would give the same power, and this, instead of requiring to be floated like the paddle wheel high out of the water by sufficiently strong barges or punts, can be immersed and attached not only to barges and punts, but to a buoy, wire rope, boom, bridge pier, piles, or other fixtures suitable to the various situations.

"The Ota?o sluice head, by the Gold Fields Regulations, being equal to 95 cubic feet of water delivered per miaute, machines of the above dimensions will raise one sluice head to an elevation of 70 feet, or 7 heads 10 feet, and this without intermission day and night. "The advantage of the screw when made of timber (as I would support) is easy in its construction and repair — this fact should be particularly noted; besides, the screw is the only portion of the apparatus, whether for mills or pumping gear, that need be subject to accidents from floods. Accidents from floods can also be avoided by drawing the screw into the banks till the danger from drifts is over. On the Clutha, with its great body of water, the construction of the screw need not now be scientifically correct, but may be of the rudest description, the fault in form being amply compensated for by the superabundance of power. Thus, the screw may be easily made by a common carpenter and blacksmith — in fact, out of an old gin case and a piece of scantling I would engage to make a very effective two horse-power machine. The contrivance then, Tarn sanguine in stating, supplies that which is wanted by the sluicing, dredging, pumping, and other enterprises on the banks of the Clutha — viz., an inexpensive and simple machine for economising the power of the current. The nature of the contrivance is simple. A model is now on the table for inspection. I will be happy to show it at work in the stream of the Water of Leith, at any time the members of this Society may appoint, when they could judge of its effectiveness themselves.

" The model will be seen to be made of wood, in the make-shaft fashion much had recourse to on the diggings, the only portion of it executed by skilled labor being the brass force-pump and indiarubber tubing. The screw (or more properly speaking fan wheel, as the blades in this little example are plain and not to to the helical curve) is 15 inches in diameter. The blades are set to an angle of 20 degrees to the disc, and in a two-mile current the revolutions are once per second nearly. The pistons of the pump are worked by a crank, and, being single-act-ing, propel its contents once per second. The diameter of the cylinder is threequarters of an inch, and stroke of piston 2 7-10 th inches. The quantity of water per stroke is therefore 1 1925 cubic inch. At the stroke rate of speed the quantity delivered therefore is 71 65 cubic inch per minute, or 59 "5 cubic feet, equal to 3689 gailons per diem of 24 hours. This little model would, therefore, liberally supply the wants of a house of the largest class, and the first cost (not including piping) would not be over L 4 or L 5 sterling. For town supply, the screw, p\unp, and gearing would require to be designed for the population ; but taking for example one of the largest force pumpa in. the

works of Messrs Burt, of this city, I ficd. it to be 4in in diameter, Bin stroke, single action once per second. This purapin constant operation would deliver <fes cubic feet per minute, or 5025 cubic feet, equal to 31,155 gallons for 24 hours, which would amply suffice for the supply of a town of 1000 inhabitants. Had the water supply to be raised 100 feet above the ievel of the river, such as would be necessary for Balclutha, Alexandra, Clyde, or Cromwell, as one-horsepower raises 5*28 cubic feet to that elevation per miuute, this power, allowing amply for friction, would suffice for the above service. So, were a screw applied to the pump revolving in a current of 7 miles per hour, one of 3ft 6in in diameter would do the duty.

" The cost of the apparatus complete, delivering water at the top of the bank (not including street pipes, &c.) will, of course, vary with the nature of the position and relative facilities afforded. Where the river is narrow, the screw and pump would best be held by a wire cable stretched across the torrent or arm of the river. Where the banks are steep and rocky, a boom secured by stays and guys would be the best mode. Where the river is wide, a small punt or even a barrel or buoy, might be used, and so forth. Iv either case the cost could not vary very much, so, taking the first by way of example, the following is an approximate estimate : —

" In this case, for the avoidance of damage by hsavy floods, arrangements would be made to elevate the wire cable and draw the screw and pump in shore till they had abated.

" 1 have already given the dimensions of a screw required to raise one sluice head (95 cubic feet per minute) 70ft above the level of the river, and an approximate estimate of the cost of the same would be as follows. The doty required would take a single acting pump 14in in diameter and 18in stroke per second, or double acting, llin diameter and 14.5 in stroke of same velocity.

Of course the cost would be much modified by position and the relative facilities given by the state of the river, its banks, its rocks, its currents. En applying the large machinery, it would be advisable to choose such sites as would afford rock foundations for the pump and gearings, so aa to avoid the necessity of supporting the same by cable or punt, and in such, cases the pej manent material (cast iron) might be used solely for the piping.

"As the altitude of water to bn raised in many parts, especially below the Teviot, does not require to be so great, of course much reduction in cost could also be effected. ' This remark is also particularly applicable to the service of pumping water from river bank claims carried on below the level of the stream surface, where the height to be raised is generally small.

"In many parts of the gold fields of Otago large capital has been expended in bringing water to claims on the banks of the Clutha, now worked but. The cost of bringing in water when not available for other claims thus remains a loss. Thus a great advantage is gained, under such circumstances, by the introduction of the contrivance and machinery proposed, inasmuch as the plant can be removed to other localities, and re-erected for new operations."

iO fathoms of 3-inch galvanised £ s. d. iron wire rope ... ... 815 0 ?ump ... . ... ... 10 0 0 icrew 10 0 0 50 feet of 2-inch indiarubber tubing at 2s 6d per foot ... 18 15 0 .50 do do iron piping, at Is 3d per foot ... ... ... 9 7 6 Carnage and labor of erecting ... 50 0 0

* 8 - d - Pump ... 65 0 0 Screw ... 20 0 0 >0 fathoms of 4Jin galvanised iron wire 45 0 0 .50ft of leather 6in hose, at 5s per foot 37 io o .50ft of cast iron 6in pipes, at 4s per foot 30 0 0 Carriage and labor (say) ... M . 100 0 0 £297 10 0