Salt River herald., 1878-08-03
Ore Reduction in Arizona.

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 situated the concentration works of the Silver King company, this be- ing the nearest point to their mine, at which water in sufficient quanti- ties for the use of thcsworks could he obtained. Owing 10 the success that has attended the working of the ores of the Silver King mine by the Fruc concentration process, after failure to treat them by amalgama- ton, concentration has come to be looked upon as the only method by which the ores of this district gen orally can be successfully worked. This method of handling ores has the merit of being cheap, simple and expeditions, the objections to its em- ployment being that it is incomplete and applicable only to certain vari- cites of ore. It is used with great advantage to separate, by means of specific gravity, all ores having crystalline structure, from their gan gue being especially well adapted to the concentration of sulphurets. The Silver King ores contain large quantities of sulphurets of silver, lead, antimony and copper, with a sprinkling of carbonate of the latter, about 20 per cent of the silver ex- isting as chloride or "dry chlo- ride as distinguished from horn ,ilver. These sulshurets are crys- talline and readily break from the gangue under the stamps. Thus they are practically all saved, but the dry chloride being light und cx- cecdingly friable is, at the same time carried over with the tailings. Were the metal all contained in the sul- phurets not more than 3 or 1 per cent would be lost. With mines occurring in the limestone formation, however, entirely different conditions are presented. There is a large group of this class of lodes bordering Queen Creek on the north, the ores of which are characterized by the presence of gray carbonate of lead in considerable quantities. This mineral carries the silver which blackens it but does not otherwise alter its appearance or fracture. It IS amorphous or entirely homoge- neous in structure, and therefore cannot be concentrated, because no matter how fine it be pulverized, each grain still possesses the same specific gravity, and the only result of concentration will be a separation of the coarse from the fine particles It is proposed, by parties interested in these mines, to employ this pro. cess in the treatment of this ore, but experience will, I fear, demonstrate to them, as it has to the writer, tn, folly of the undertaking. How thi: ore really should be handled re mains to be determined. It is no to be presumed that it will amalga - mate, and, though it carries a fail proportion of lead, it is not ricl enough in silver to pay for smeltin, where wood and iron (its requisit, fux) are so far distant. Still therc may be and it is even probable tha the carbonate of lead will run int, galena as soon as considerabl, depth is reached in these mines when concentration can be practicet upon the advantages.
 ANOTHER FORMATION AND 4 DIE
 FERENT ORE.
 Further south across Queen ereel which cuts through the silver-bear ing belt, the proportion of lead con iained in the ore is so small that thi metal no longer inteferes with anal gamation. Here the prevailing or Is horn silver, in itself not wei adapted to concentration, while tn admixture of the dry chloride is to great to admit of a profitable appli cation of this process. Continuin, south we find the carbonate of lea, decreases. while that of copper in creases, until this latter becomes tn 
 predominant metal. \ certain per eentage of copper has always beer considered advantageous ill amalga