THE GOLDFIELDS.

New Zealand Herald, Volume XL, Issue 12281, 27 May 1903, Page 6

THE GOLDFIELDS.

THE GOLD RETURNS.

TOTAL FOR THREE WEEKS £20,012. Doting the past three weeks the gold returns from the Auckland district have reached a total of £20,012 12s. The amount is made up as follows: —Ohinemuri, £14,471 0s 3d; Thames, £2705 Is 9d; Coromandel, £2336 10s: total, £20,012 12s. OLD HAURAKI. [BY TELEGRAPH. —OWN CORRESPONDENT.] Coromandel. Tuesday. The above company's winding plant is nearly - completed. The engine has been erected and the boiler placed iu position. The latter is now being bricked in. The tributers' crushing turned out better than anticipated, the three parties having a total of about £1750 worth of gold. Snowden and party obtained 1350z lldwt of gold from 5 tons of general ore and 231b of picked stone, worth about £400. Jamieson. and party got 2020z from 8 tons of general ore and 401b of picked stone, worth approximately £606. Jas. Davies and party, 2500z lldwt of melted bullion from 8 tons of general ore and 451b of picked stone, worth about £750. Tho exact value is not yet known, as the assays have not been completed. [The above returns arrived too late to be included in the Summary published to-day.] HAURAKI TAILINGS. IMPORTANT DEVELOPMENTS. [by TELEGRAPH. —OWN' CORRESPONDENT.] Coromandet.. Tuesdav. For some time past experiments have been in progress adjacent to the Hauraki batten - , with the object of determining how to profitably treat the large pile of tailings lying upon the foreshore, there being fully 3000 tons, containing gold 'to the value of about £11 per ton. The difficulty to be overcome was the presence of acids in the material which rendered the cyanide non-effective as a gold-saver. Owing to the absence at the earlier stage of an abundant supply of clean water, the difficulties were intensified. By the existence of the town water supply to the Hauraki battery, this drawback was brought to an end, and there is now an efficient high-pressure supply. This also materially aided the task of treating the tailings at a profit, as the necessity for handling the crude material is reduced to a minimum. For the past month -.Messrs. F. Shepherd and J. Patterson, two men of extended experience in the manipulation and treating of slimes and tailings, have been at work upon the Hauraki tailings, and have overcome most of the obstacles that presented themselves. They have practically remodelled the process oi manipulation, and have advanced so far as to treat one vat of tailings so as to leave a margin of profit. Everything now points to the conclusion that the primary difficulties are things of the past, and that the tailings will be profitably treated. It is estimated that about 60 tons per week will be treated. The methods of hydraulic sluicing are brought to bear to some extent. The tailings are washed down (by a hose playing on them) from the face to a grating, and forced through by the action of the water to the mouth of the injector. There is a gin nozzle playing into the pipe and forcing the tailings and water up a distance of 20ft to 30ft. and into an open launder. The material is then carried along the race for about 80ft into a wooden vat designated the classifier. There are several pipes and tubes running from the bottom of the classifier, carrying the cleansed tailings to the vats for treatment, separating the slimes, taking off the waste water, etc. The action of the pure water removes almost all the acids, and under present conditions the cyanide acts effectively upon the tailings. The plant comprises four tailings vats, with a capacity of 15 tons each, a raised vat containing the cyanide solution, and a sump below the tailings vats to collect the solution after it has percolated through the tailings and - out of the extractor. There are receptacles filled with zinc filings between the vats and sump which catch the gold in a state of precipitation. After the cvanide has done its work it is caught in the sump an'd pumped back into the original vat, a little chemical being added to the compound from time to time to keep it up to the required standard. At the present time the vats are emptied by hand, but it is contemplated to raise them and put doors at the bottom, when they will be cleaned out by hydraulic force.. The present overflow will also be altered, a circular contrivance being substituted for the pipes now in use. Other alterations and labour-saving devices will be introduced at an early date. The present indications are that the initial difficulties have been overcome, and the industry placed on a commercial basis. SOUTHERN MINING. [BY TELEGRAPH.PRESS ASSOCIATION*.] 1 Dunedin. Tuesdav. The Premier Sunrise Company, Macetown, crushed 170 tons for 108oz 14dwt, and treated 15 tons concentrates for lOloz 9dwt 15gr. During the past week returns have been reported from 67 dredges, the total yield being 17980z 18dwt sgr, or an average of 28oz per dredge.