GRACE OAKLING BATTERY.

Auckland Star, Volume XXXI, Issue 63, 15 March 1900, Page 7

GRACE OAKLING BATTERY.

The opening of the Grace Darling Gold Mining Company's new mill took place on Monday, 19th inst. The visitors were received by Mr Chas. Scherer and shown over the whole mill, commencing- with office, which is a large, well-furnished room. Next is the assay department, which is fitted tip in tliet most modern style; and adjoining is the extraction house, which will contain four extractors (or zinc towers), and is a well lighted, large and roomy building, having concrete floor. The engine house contains one of the most improved Corliss engines, GO horse-power, by Tang-ye and Sons. The steam is supplied by an 84 horsepower Babcoek patent water tube boiler. The engine vests on a solid concrete foundation, and together with the boiler has a very substantial and workmanlike appearance. In addition to the engine there is a five foot Pelton wheel, the water for which is supplied by fluming some 52 chains long, and is led into the wheel by wrought iron pipes 18 inches diameter, having a head of 110 feet, so that during the winter months the plant can be driven by water power. From the engine room the visitors passed on to the mill itself, which is fitted up in a most complete manner. Only 10 stamps are in use at present, but everything has been arranged and is ■ nil ready for fixing- 10 more. The framing and mortar blocks are all in position ready to receive the extra boxes and stamps' at any time. The stamps now in use are from the celebrated Union Iron Works of San. Francisco, and weigh llOOlbs each, and on Monday were running at the rate of 90 drops per minute with a fall of G inches. The visitors were loud in their praises of the substantial and compact appearance of the ■framing nnd the very small amount of vibration. The ore to be treated is received direct from the mine trucks into the mill, and after passing through the grizzly and rock breaker falls into a large hopper, and from there is led into the self-feeders which

supply the boxes so that the whole

system works by gravitation, and there is no unnecessary handling-. The rock breaker is a Gates No. 2, with a capacity of 8 to 10 tons per hour. This mill being on the wet crushing1 principle when the ore leaves the boxes it passes over the usual copper plates and is carried by launders into the vat shed. At present there are only six vats, but provision is made for 12. These vats are arranged in pairs, three above and three below, the whole resting- on massive foundations of concrete, the upper ones being- supported on trussed beams. When these vats are full they each hold about 60 tons, so that great strength is necessary to keep everything- right and secui'c. The ore pulp is first received into the upper vat, where it is allowed to. settle, after which it is dropped through trap doors into the vat below and is there treated by cyanide. In passing through and over the works the visitors were very much impressed with the very thorough manner in which all the work has been designed and carried out.