C.—3

8

to operate a powerful Sampson turbine, the water-level being raised 30 feet by means of a dam across the river near the claim. The power thus obtained is applied to centrifugal pumps, which raise the water to such a level as to enable its being used ordinary manner for hydraulic sluicing and elevating.j,jThe following comparison of the conditions prevailing and the plant installed at the Tamaiti Claim, New Zealand, and at the Rogue River, Oregon, U.S.A., will serve to illustrate that this system may be successfully applied to either large or small concerns : —

Note. —The total cost of the Tamaiti plant and equipment, including the dam, was only £3,000 (approximately). Alluvial-mining operations at Ross Flat, Westland (a plan and sections of which accompany this report), after many years of inactivity, are about to be re-established by the Ross Goldfields (Limited), which company has been formed for the purpose of unwatering and working the deep alluvial gravels, which have remained unworked since 1887, when, through the inadequacy of the pumping equipment then employed, an inflow of water from old workings flooded the mine then b( ing worked by the Ross United Company. The present company is capitalised at £80,000, of which £50,000 is to be devoted to working-capital, with shares to the value of £10,000 held in reserve for future issue for a similar purpose if required. The following is the scheme, evolved for the most part by Mr. H. M. Smyth, M.A., the company's electrical engineer, by which it is proposed to recover and exploit this goldfield. It is proposed to utilise water-power, conveyed from Lake Kanieii, which lies at a level of 422 ft. above the sea, and is supplied by a catchment area of 16 square miles, by the already-constructed Kanieri water-race, the property of this company, for a distance of about six miles to the Kanieri Forks, where it will be used for the purpose of generating electricity for transmission to Ross Flat, there to be utilised as a motive power to work centrifugal pumps, hoists, lighting, and all mining machinery, The capacity of the water-race is 40 cubic feet per second, and it will deliver into the pipes at an effective elevation of 240 ft. above the Pelton wheels at the power-house. The power will be transmitted from thence about twenty-two miles to Ross Flat, the line of transmission for the greater part of this distance following the main road and the railway-line. The pumps employed are designed.to deal with' 3,500 gallons per minute under normal conditions, from a depth of 400 ft., and 4,500 gallons per minute in case of an emergency. It is further proposed to construct a drainage adit to remove the flood and surface water to a depth of 90 ft. below the present surfacelevel at the mine, thus reducing the pumping of the water from the deep levels by 90 ft. of vertical height. It is then intended to open out and repair the main pumping-shaft of the old Ross United Company, and to place the electrical pump-motors and new pumps in that shaft, and to unwater it to its entire depth —viz., 390 ft. The next operation will be to unwater all the old workings of the Ross United, Cassius, and Morning Star mines, together with all the old claims on the Ross Flat area. A new working and winding shaft will then be sunk in such a position as to command the efficient and economical working of the entire flat. This shaft it is proposed to sink 100 ft. deeper than any of the present known workings, so as to open out new gold-bearing deposits, and, if possible, reach the main bottom, which has never yet been done at Ross Flat. The present intention is to open out drives, and work the rich auriferous layers which had to be abandoned by the Rost United and Cassius Company owing to inundation. These auriferous layers averaged in value lis. 4d. per cubic yard, and during the last two days of the Cassius operations £325 was reported to have been won. The cost of mining did not then exceed ss. per cubic yard. The present company contemplate dealing with at least 300 cubic yards per shift, and propose to work three shifts per day. A contract has been let for the erection and installation of all the electrical plant from trie power-house to the mine, to be completed by April, 1909. The power-line will consist of three hard-drawn copper wires, No. 5, B. and S., having a cross-section of 33*102 circular mils, and diameter 0*18194 in. The lines are to be mounted in the form of an equilateral triangle of 3 ft. side, one on the top of the pole and one at each end of the cross-arms. The pumps are to be two Worthington multi-stage turbine pumps, connected to three-phase squirrel-cage type of induction motors, each pump to have a capacity of 1,000 gallons per minute ; also two multistage turbine sinking-pumps of a capacity of 750 gallons per minute. The Pelton wheels are to be of the twin type, with double jets, giving 550-horse power each, also one small Pelton of 25-horse power. Two three-phase alternating-current generators will be used. The above undertaking will be watched with considerable interest by the mining community, for, in addition to the exploration and development of the deepest gravels yet mined, it is the first attempt that has been made to apply hydro-electric power to deep alluvial mining in this Dominion. These operations have been subsidised by the Government to the extent of £15,000 from the item specially voted by Parliament.

'amaii iold-mining Company, New Zealand. ;ago, Rogue River Company, Oregon, U.S.A. Water utilised for turbines Head at turbines Turbine-installation 73 cubio feet per second 30 ft. One 26 in. horizontal single discharge, Sampson type Belting 3,538 cubio feet per second. 21ft. 4 units of four turbines each, vertical drafttube type. Transmission-gear, and a line shaft connected directly to flexible couplings attached to the pumps. 4 units of 5 step 18 in. centrifugal type. Power conveyed by Pumps (to claim) Pipe-main (to claim) Height pumped (to claim; Pumps raise (to claim) .. 1 unit of 4 step 10in. centrifugal type (Tangye) 10 in. diameter 160 ft. 6 to 6-5 cubio feet per second (one pump) Various (small) .. ■. ' Not gauged 22 in. diameter. 430 ft. Each pump 20 cubio feet per second (four pumps employed). 3 in. diameter (four employed). 1601b. per square inch. Size of Giant nozzles Pressure of water at nozzles