MINING.

Press, Volume LXIX, Issue 20881, 14 June 1933, Page 11

MINING.

LAWSON'S FLAT COMPANY.

The Lawson's Flat Gold Sluicing Company commenced active mining operations last Tuesday, and the plant has since been working uninterruptedly. The yardage being treated, with a 31 inch nozzle, is up to the quantity set out in the prospectus. The debris has been practically removed from the faces, and sluicing on the latter will commence to-day. Tho mining history of the Callaghan's district where the claim is situated dates back to the 60's, when the most accessible leads were hand worked. Then followed in the 70's and 80's extensive sluicing operations. The government of the day spent heavily out of its goldfields revenue in providing water races, but the physical difficulties in getting water to some of the proved gold-bearing faces were insuperable and as the more accessible belts were worked out the industry gradually waned. Power is now available to overcome these difficulties, and the Lawson's Flat Company is utilising it in a direction which marks a new era in go!d mining on the Coast. The claim, as a matter of fact, is on a plateau about 350 feet above the only available water supply. For this reason the fortunes of the company are invested with general interest. The success which the trial run of the plant indicates is assured, will establish a standard for other mining enterprises to adopt, and incidentally may remove the scepticism of some of the old mining shellbacks.

The area of Lawson's Flat comprises 90 acres, 21 of which have been intensively prospected. The 21 acres will provide work for 5£ years, and the balance of 6!) acres and a further area of 100 acres are being prospected. The water required for sluicing is taken from a Government water race at a distance of about halfi a mile from the claim, and is pumped against a total head of 500 feet at the rate of 2(300 gallons a minute. .After allowing for frictionnl losses in the pipe line the head available at the nozzle for sluicing is 100 feet. The plant consists of a two-stage turbine pump constructed by the Pulsometer Engineering Company, of Reading, a pump universally in use in mining enterprises. It is driven by a 500 h.p. Crompton-Parkinson motor, the electric power being supplied by Westland Power, Limited, from their hydroelectric station at Dillmans. The improvements in the design and efficiency of the modern multi-stage centrifugal pump which is now universally used for forcing water to great heights, make possible the method of operation which has been adopted at Lawson's Flat. A difficulty when high levels are sluiced is the disposal of the tailings. In a claim situated as Lawson's Flat is, and where the values warrant >t, the cost of pumping the water is offset to a large extent by the natural facilities provided for disposal of the tailings, which in the present case discharge with a steep drop into German Gully some 200 feet below the sluicing face. The 500 horse power motor ensures a nozzle delivery of seven heads of water. In the trial running more than this quantity was discharged. A tunnel 750 feet long to convey water from the race to the pump site, a pipe line 3000 feet long, the pumping and power, unit, two tailings tunnels, a tramway, and the goldsaving tables, reflect credit on the designing engineer, Mr J. S. Langford. whose original plans it was found necessary to alter in only one or two unimportant respects. The checking of the prospecting and the reporting on the mining features of the proposition were undertaken by Mr John Henderson, mining engineer, and'the engineering features were reported on by Mr R. A. Campbell, civil engineer. A representative of "The Press" saw the plant last week, and its construction obviously bore the hallmark of efficiency. A satisfactory feature from the shareholders' point of view is that everything has been carried out according to the prospectus promise. Capital costs have been exceeded only in instances where the increased exchange on imported material was concerned". The promise of operations commencing in June has also been realised, a fact largely due to Mr C. Cook's control of the construction work. The prospectus of the company was filed with the Registrar on January 28, so that active operations practically four months from that date show that there has been no dallying with the work. i GOLDEN DAWN COMPANY. Reviewing the operations of the company at the annual meeting at Auckland on Friday. Mr J. Farrell, chairman of directors, said the total tonnage treated in 1932 since operations commenced was 9187 tons, including 243 tons treated in December, 1931. After payment of duty and cost of sale this realised £30.948, or £3 7s 5d a ton. The costs of mining had been above normal, due to the extreme hardness of both the reefs and the country and the absence of cleavage between rock and reef. In addition, the widths were narrow, and as the drives and stopes were wider than the reefs a good deal of country rock had to be taken out as well as reef matter. The costs of mining and overhead during the year were £28,497, equal to £3 2s a ton. The directors had been making every effort to increase returns and decrease costs. All ore winning work was now let by contract. The mining costs were declining, and during the eight weeks from February 28 to April 22 the figures showed a profit of £B7O, of which £362 was spent on development. As values were found inconsistent in the higher levels, the company proceeded with extensions at No. 3 level on Na 1 and No. 3 reefs, and these both indicated that values continued right up to the face on both reefs. Statements had been macle that the battery was not up to date, but they were incorrect, the saving being 95 per cent, of the values in the ore. Profit for the half-year ended December 31 was £990, increasing the balance in the profit and loss appropriation account to £1465. The retiring directors, Messrs Farrell and C. Adams, were re-elected. | OPERATIONS AT WAIHI. The following information has been cabled to the London office of the Waihi Gold Mining Company, Ltd.:— No. 3 Level—North branch Martha lode crosscut: At 31 feet up the J-ise showed only country with stringers of quartz of little or no value. Crosscutting is stopped and another rise has been commenced at CO feet west. No. 4 Level—At 214 feet in the north-west prospecting crosscut we have driven to the east 19 feet, the lode in the face being two feet wide, and to the west 18 feet, where the lode in the face is 1? feet. wide. The quartz in both drives is of good grade. No. 5 Level—At 103 feet in the northwest prospecting crosscut we have driven to the east 20 feet, and to the west 15 feet. The leader is about six inches wide and of little or no value. Junction No. 6 Level—At 68 feet south-east from the Empire lode we have driven north-east 11 feet, the assay value being 59s 6d a ton, and to the south-west nine feet, the assay value being 40s a ton. The vein is about six inches wide. . No. 11 Level, 80 feet sub-level—- ' Sinking has been stopped in the winze at 51 feet down and we have comImenced driving west of the face of I the Royal lode from No. 4 shaft, south--1 east crosscut at No. 12 level.