THE SYLVIA GOLD MINING COMPANY'S PLANT.

New Zealand Herald, Volume XXVIII, Issue 8501, 27 February 1891, Page 6

THE SYLVIA GOLD MINING COMPANY'S PLANT.

. OBOM .OCR OW N , CORRESPONDENT. J '-''" . •■'"■■■ Thames, Thursday. This company's new redaction ;plant has now been in lull swing for several weeks past, and has fully answered the purposes ' for which it was erected, namely, the concentration of all the heavy refractory and complex minerals contained in the ore broken from the large reef opened up in the company's own mine, such as galena, zinc blend, copper, and iron pyrites, with which the ore is heavily charged. To deal successfully with this class of ore was a problem which at first was very difficult to Bolve, but Dr. Scheidel, a German mining expert, who is also the managing director of the company, after much experimenting and knowledge gleaned through visiting the Mount Bischoff tin mining works in. Tasmania, came to the conclusion that what was wanted was machinery which would concentrate all the valuable minerals in the ore, and permit all worthless substances to pass away. Consequently on his recommendation, and under his sole control, the present large plant has been erected at a cost of about £10,000. The plant comprises ten head of stampers, of the heavy American type, capable of treating 25 tons of ore per diem. At the foot of the stampers copper plates are laid down to catch what free gold there may be in the ore. From the tables the flow passes into four classifiers, where the heavy minerals are saved, and the" lighter ones pass on into jiggers, of which there are six. In these jiggers are placed beds of heavy mineral broken to a size of small beans, and in passing over these mineral beds the heavier pari tides of minerals contained in the tailings percolate down through them, and the lighter slimes pass on to the large tanks. , From thonce the slimes fl'V" on to large revolving double tables 12 feet in diameter, where more of the lighter minerals are saved, and from these tables into I large buddies, whore the last residue of the mineral is saved. It will thus be seen that the process is purely one of concentration, -except the catching of a little free on . the copper plates adjoining the stampers, I and that the plant erected is exceedingly suitable for the purpose. The idea which forms uhe basis of the concentration process is to classify the crushed ore into two classes—the slimes and the coarse mineral—each of which class is treated and con centrated by special macninery. The special feature of the plant, however, is the treatment of the slimes, which so far ha? boon greatly neglected on this and other goldfields, so that it may be called a totally new departure for treating golden ores. The greatest attention has been paid to this subject, and the rotary tables which have been erected for the purpose do their work in an excellent manner. From the first start of the machinery to the present* moment everything has worked in a most satisfactory manner, with the resuit ) that a large quantity of valuable concentrates have already been accumulated. Up to the present, however, the stampers have 1 been capable of treating more ore than the two double revolving tables and the two buddies could deal with, consequently a very large quantity of half-finished concentrates have accumulated, therefore during the past few days the stampers have been idle to allow the rest of the machinery to catch up upon them. This difficulty, however, will beat onco dispensed with, as a large three-decker rcvolvingtableandanother large buddle have just been erected, and will be at once utilised. With these in operation, the continuous run of the whole plant will soon certify what the experimental run so far has proved, for it has come fully up to expectations in the treatment of ore in which the saving of bullion was previously neglected. It may be mentioned enjxis-iant that the whole of the machinery is driven by one of Messrs. Price Brothers' Pelton wheels, the water for driving which is brought to the battery by means of a race 37 chains in length, and at night time the building is illuminated by means of the electric light. In the erection of the plant the company deserves great praise, for it was carried out in the face of many difficulties, but under the supervision of Dr. Scheidel and an efficient staff of competent workmen, together with the expenditure of a large sum of money, these were all successfully combated against, and a rich reward -is evidently in store for the plucky shareholders, for assays'made of the concentrates accumulated so far have proved them to be rich with the precious metal. The success of the company will qlso tend to bring the Tararu district into more prominent notice than it has been for years past, as there are evidently many large lodes existing there which only require special treatment to enable them to pay handsomely. At the company's mine, which is connected with the plant by means of an serial tramway three furlongs in length, large blocks have been opened up upon the reef for stoping both at the upper and lower levels under the management of Mr. W. Tregoweth. At the low level a length of fully 300 feet is opened up, with backs uf about 140 feet to the level above. Two runs of rich ore have been met with in this length, the first being about 130 feet long, whilst the other is now being developed. For the entire length of the drive the reef will average 5 feet in thickness, but varies from 2 and 3 feet up to about 8 feet. The richeso run of mineral, however, generally runs in one strong band, ranging in size from nine to fifteen inches, sometimes being on one side of the reef and thon on the other, but the whole bulk of the reef is more or less impregnated with mineral, and is all saved for treatment. A rise has been carried up from this level to the one above, and a leading stope has been taken along for about 20 feet .from each end of this rise, which is upon the first rich run of ore, and a leading stopo has just been started on the second run. The western face is still being pushed ahead ou this latter run, the reef being about three feet in thickness at the time of my visit. At the top level driving westward has just been commenced, and a leading stope carried along- about 50 feet upon the first run. Here the reef is of similar size and quality .is at the level below. It will thus bo seen that the mine is well opened up, and that no flitliculty ie likely to be experienced in obtaining a. sufficient supply of quartz for the company's reduction plant. In fact, a plant double its size could easily be kept supplied, for in addition to the reef beinjj of large dimensions, it is also very easily worked, and scarcely ever requires the aid of explosives to break it out. I understand that it is probable a now low level, which will provide an additional 300 feet of bucks upon the reef, will shortly bo commenced jusb below the battery site. This work will be one of considerable magnitude and expense, for it will require no less than 3000 feet of driving to intersect the reef, but the prospects at the now low level appear to warrant such an undertaking. Mr. H. W. Kayser, of the Mount Bischoff mine, Tasmania, has been thoroughly inspecting both the mine dnd plant during , the past week, and I am given to understand that he was very highly impressed with the carrying out of all the details in connection with the company's plant, and the satisfactory results which have so far attended the treatment of the ore, and also of the excellent prospects of tho mine, which he very minutely inspected. He returned to Auckland yesterday morning (Wednesday), in company with Dr. Scheidel

A very old New Zealand identity, an Indian patrob, expired, apparently from old age, Jast week. It was the property of Mr. Rogers, formerly the proprietor of the Criterion Hotel, Qbahuhu, and was for years a popular feature of the hotel, for Polly's power of vocalisation and quaintness always attracted a great deal of attention. The bird was brought by the 70th Regiment, which came direct from India, in May, IS6I, and it was then full grown, and probably several years old. The pet of tne regiment was presented to Mr. Rogers, who has retained it up to the date of its death, after a residence in New Zealand of nearly thirty years. The Lawn Tennis match, in the second round, for the Championship of Auckland between Messrs. W. B. Morrison and J. R..' Hooper, which was interrupted by the weather on Saturday last, will be played off rfe novo at the Eden and Epsom Lawns on Saturday, the 28th instant, ac three p.m. Tennis players and others are invited, and will witness a good meet if the players come up to time in the form which produced Saturday's sample of play. At the same time and place T. F. Upftll meets A. Tempest, and a close contest in this event is expected.