Arizona weekly enterprise., 1881-12-03

place; but l found 1t necessary to attach a second fireplace, in order to obtain a uniform roasting. On account of the heavy spar, fahlore and galena, the ore cakes very easily, and in order to avoid this, and loss of silver, the ore has to be roasted at very moderate heat; but this would be impossible to do with only one fireplace, as the ore would either not have heat enough at the farther end from, or too much at the nearer end to the fire.
 After the charge of ore is in, the fur mace Is set in revolving .motion, and | fire kept in one of the fre-places, the 1 flame traversing the furnace, and smoke and gasses escaping throuh the opposite fireplace and flue into | the dust chamber. After a lapse of one hour, fire is made in the oth- CT fire place, the dampers reversed, and 1 flame and gases allowed to pass through | the furnace i'll the opposite direction. l This changing of the fire is kept up at hourly intervals, till the charge is roasted.
 This system of fre-places and fues l proved to be of great advantage, by obs 1 taining a very uniform roasting, the ore l from both ends being chloridized up to the same percentage, while in the old construction the ore from the further end shows from five (5) to ten QO per cent i less chlorination.
 Glancing over the above list of miner als, of which the Silver King ore is com posed, the base and rebellious nature of the ore is apparent. The worst feature of the ore is the simultaneous presence of antimonious fahlore and zincblende, by which great chemical loss of silver IS caused by roasting. There are cases in which the loss in roasting has been as high as fifty (50) per cent. By actual exper- iment with the furnace, l found the loss in roasting Silver King ore to be thirty-eight (38) per cent, if the same is subjected to the common way of roast ing; but I succeeded, by applying steam during the time while chemical action takes place, in reducing the loss to min imum, and not exceeding two @ per cent. The use of steam in roasting had been recommended by Mir. Pattera, of Joachimstal, Bohemia, and it's beneficial and powerful effect l demonstrated with Silver King ore, to the advantage of the company. 1 do not hesitate to assert that without the application of steam, the com pany's ore could not be treated success fully, as the loss in roasting would be enormous. It IS true, the use of steam costs more fuel and a delay i'll roasting, but the advantage gained Is so great that these questions can not be taken into con- sideration.
 The furnace is charged with about three and half (3!) tons, and the time re- quired for roasting Is from twelve (12) tC { 5 fuel This long time Is caused by the low heat at which the ore has to be roasted and the large amount of zincblende contained in the ore.
 The average chlorination of the ore, as ascertsined by assay of sixty-seven (67 furnace charges, proved to be 94.4 pel cent, while in some cases 1t came as hlgf as 96. 5 per cent.
 IIXIVIATION.
 After the ore IS discharged from the furnace, it is moistened with water, anC elevated to hopper, whence by means o cars running on track above the vats, il is charged into the liXiviating vats. There are five (5) of these vats, each ten Q0 feet in diameter and three (3) feet deep provided with @ filter bottom, and an out let under the same for the escape of thu solution. As soon as one vat is charged with the proper amount of ore, stream } of water is allowed to enter on the top l which, in passing through the ore and es , caping under the filter bottom, dissolve
 and carries off the base metal chlorides
 After these are removed from the ore, stream of hyposulphite Of lime is applied which desolves the chloride of silver. The solution containing the silver i
 now conveyed to the precipation tanks where 1t is precipitated with solution O , sulphide of calcium, which chemical i prepared on the premises by boiling lime sulphur and water, and besides the sal
 used in roasting, is the only chemical con sumed in the process.
 The silver, when precipitated, settles a i, sulphide of silver on the bottom of tn, the vats, the clear solution of hyposul I phite of lime Is drawn of by means 6 four (D outlets, at different levels of tn,
 vat, and conveyed to lower tank (pump , tank), whence it is pumped up to the res . ervoir and ready for reuse This solven
 is prepared only once, as the sulphide O , calcium, by precipitating the silver changes into the hyposulphite, or tn
 
 of silver, and if proper care is taken in
 creases in strength and volume, which
 actually the case at the company's works
 where we are obliged, from time to time . to let part of it flow into the waste, as Y increases beyond our use
 Q When enough sulphide of silver has ac
 cumulated on the bottom of the precipita tion vats, it is discharged through an out r let close to the bottom and conveyed, b n means of troughs, to a system of filters
 and the solution strained from the silver This, however, leaves the precipitate i : too wet condition to be convenient fC ,, the subsequent operation The use of t press had found by former experienc f impracticable. In order to overcome tn
 drawback and save fuel planned eel
 trifugal filter, acting on the principle (
 the sugar centrifugal machines, by whic 1- the precipitate will be strained and drie l. in a very short time. This machine wi
 soon be in operation.
 h The precipitate from the filters T. charged into small reverberatory fu h mace, to burn of the surplus sulphu During the operation the precipitate q le minishes a great deal in volume, ar l. when finished is covered with wire of s er yer, moss-like, and contains eighty -thr r; (S3) per cent bullion. The burned pr T. cipitate is charged into crucibles, melt, er with iron and borax, and poured in h. moulds. This finishes the manipulation i' Consulting the history of mining nd find there are but few mines reported us having paid from the surface down, al 
 ne the King is one of the few. It has pa <, every expense of development, the cc ,2 of erecting steam hoisting works al
 water works; twenty-stamp mill lixivi