THE GOLDFIELDS.

New Zealand Herald, Volume XXII, Issue 7514, 18 December 1885, Page 6

THE GOLDFIELDS.

THE WATKR-JACKET FURNACE. [VROM OUR OWN CORRESPONDENT. | Thames, Thursday. Now that the water-jacket furnace, introduced by Mr. LaMonte, is in fall blast, a description thereof may not bo devoid of interest. As my knowledge only consists of what I have seen and heard, I may be the more successful in conveying some idea of the furnace to the mind of the untechnical reader. lam at a loss to know what, in appearance, would give a fair impression of it. It bears » strong resemblance to some tea-canisters of bygone days, only that the neck of the furnace is longer. However, let the reader take a bottle—say a Kerfccd sauce bottle—imagine that the neck is much wider, and he will have formed some conception of the shape of the furnace. It is an upright iron cylinder, not round but oval, perhaps 2S or SO feet in height. I may here state parenthetically that all figures will be approximate. The lower part or body of the furnace is about 7 feet by 8£ feet in width, or, if the term is excusable, diameter ; but at the top, at the feed holes it is about 8 feet by 4 J feet, and the upper part (corresponding with the neck of the bottle), say, 3 feet in diameter. The cylindrical furnace stands upon a base about 10 feet by 5i feet, and 3 feet deep. The base, however, conceals the lead bath, the home of the bullion, which is 24 inches deep and 7 teet long. The first 5 feet above the bath is the water-jacket. Now that simply means that instead of one skin there are two, with a space of eight inches between them, and this eight inches contains water which is constantly flowing by means of one pipo la, and another one for egress. For clearness, let me repeat that the lowest five- tbe furnace (by which I meau our friend the bottle, and exclude the foundation and bath) is always surrounded with eight inches of flowing water. The use of the water is to preserve the furnace, and prevent the fire affeoting it, The part covered by the water-jacket is the real smelting point. The furnace is composed of iron about }.inoh thick. Let ns now proceed half-way up the furnace to its shoulders, at the point where the neck joins on to the trunk, and what do we find ? Simply two square holes on each side. This is really the top of the furnace, the narrow portion above that being but a sort of chimney. Just a little above these holes a huge pipe, almost as large as the neck of the furnace, leads away from it, ami fqr my present purpose the description is complete. Now for the smelting. IV ell, these square holes are the mouths of the furnace whereby it is fed, and it is supposed to devour 20 tons of good smelting ore in the 24 hours, which it swallows, with given quantities of coke, lime, and iron, to assist digestion, according to the dietary scale prepared by Dr. Stearns. There is first a layer of coke, then the ore and fluxes. ; If anyone labours under the impression i that the water jacket claims cousin- i ship with, or bears any resemblarice to, the burning liery furnace of which' the three young men mentioned in the Book of Daniel so unkindly spoiled the patent and rendered obsolete, let him disabuse his mind of it at once. No, the fire never comes up to feeding mouths, and there it is always dark on top owing to careful feeding. What goes up the chimney— ».r., the neck ? Nothing. It is closed at the top. All smoke and vapour arising from | the furnace fires are intercepted just above i the feeding-mouths, aud are carried along the large pipe already alluded to away to the condenser. Here any escaping lead or other minerals, excepting a slight moiety, are caught, and the smoke then ascends the chimney-stack. The scientists tell us that, in course of time, this smoke, tainted with lead and mineral matter, will destroy vegetation near to the furnace, and render the inhabitants pale and wan. Having finished upward let us now go downward. Not being impervious, like Shedrach and mates, we cannot proceed by the interior and watch the process of digestion, SO a glance at the bottom, outside, must suffice. From the bottom of the furnace running on the top of the foundation, to its outer edge, are two little drains. These convey the slag, that is the refuse which floats on the top of the molten bullion, to ▼easels placed for its reception. And now for the precious fluid itself. Well, at the top of the foundation, outside the furnace, is a square hole, and as the bullion accumulates in the bath, it finding its level, rises towards the top of this hole. The molten mas is then ladled out into moulds, capable of holding SOlbs of metal; which done, it looks like ingots of lead. The furnacing is finished, but the cupelling has yet to come. The ingot, or button, is as yet principally lead. The ingots are placed in the cupelling furnace, the lead oxydised with litharge by means of steam playing at a high temperature, and the pure bullion, ready for shipment to England, left in the cupel.

There is a steam engine which serves two purposes, to drive the blower and,work the ■tone crusher. The blower, or bellows, if the furnace creates a powerful current of air, which is conveyed up to the furnace by a pipe, and carried into it by means of several smaller pipes, called tyers, inserted near the bottom of the furnace. With such a blast, and proper fluxing, once the (ire is lighted it must burn with a fervent heat. The building is of galvanized iron and about 45 feet long by 25 feet broad. It may be said to be divided into three nearly »qual parts below, the northern end being devoted to the cupelling and refining furnaces, the middle one to the furnace, whilst the southern compartment contains the engine and blower. The upper story is used for storage ©f ore, full, and fluxes. The stone crusher is alio situated on this fiat, and it is here the furnace is fed. The atone crusher is a simple, insignificantlooking contrivance. It seems to consist of, primarily a not very large bole or hopper, into which the stone to be broken is cast. Falling as far as it can it gets between two plates, each having a rough surface. One is stationary, but tho other movable near to the other plate at the bottom, it seems to be always striving to get as close to it at the top. It is this strife that crushes the stone. Of course the ■tone first reaches where the plates are farthest apart. Between the effort of the one plate to reach tbe other and the slight oscillation of odc of them the stone ia soon broken ; then falling lower, and being still subject to the harsh treatment from the plates, one still endeavouring to reach the other, and getting nearer each other as the ■tone falls further into their jaws, that which was * second previously a fine large lamp emerges in many pieces, the majority probably about the size of a small egg, admirably suited for feeding the furnace. Mr. Stearns informs me that this orusher is capable of putting through 80 tons in the twenty-four hours. It would be, I presume, superfluous to inform your readers that the furnace is situated in the site of the old Prince Imperial battery, on the beach, nearly opposite the big pnmp. As it is some distanoe from the street an inclined wooden dray road leads from the main street to tbe second storey, whither all stuff intended for the furnace is conveyed. [by mligraph.—own correspondent,] Thamks, Thursday evening. The furnace is putting through fourteen or fifteen tons of ore daily. The iron for flux is running short, and it is feared the furnace will have to stop to-morrow. Slabemarkbt. —Cambria, sellers 17s 6d, buyers 16s fid ; Cross, sellers Is ; Moanatairi, sellers 8s; Imperial, sellers 3s 6d ; Caledonian, sellers 3« 6d ; Golden Crown, sellers Is 9d, buyers Is 6d. The Moanatuari.—Mr. Vivian has resigned the managership of the Moanataiari mine, the resignation to date from January 31st next. MINE MANAGERS* RKPOKTS. Crown. —For tbe past week two shifts of two men each have been pushing ahead Dm leading stope on No. 2 reef; on mam level. The lode It from tight to Bine feet tbl :k, and tn-nav noma of the heat stone yet obtained in the mine wa» broken nut of the bangld{;inswall portion. Next week I shall be able to brln/ along the second stupe, the leading stipe being sufficiently ahead to enable me to keep both stoats join/. bob.—During the past week we have been advancing tbe slopes north and south of No. 1 winze, above the intermediate on the .Scott reef, which is Jiroduclng a fair class of crushing dirt, for about 20 est on each aide of the winze. During the past wank we have been keeping the btttery going 16 hours per day. W« have crushed 84 tons of quartz from tbe Scotia claim, and have started all the stampers on the company's dirt, which is shaping for» payable return. Diamond.—The third stnpe has b- en carrier! along a distance of 16 feet on earth side of the winze. The quarts ii being saved for battery treatment. I have seen gold mora frequently in this stope thin I did previously, and I have conime' ced the fourth stope on the north side of the winze. In breaking down the quarts, gold could be seen in the stone freely. If It continues, I will have no difficult' in getting out a good crushing either for the battery or the furnace.