The weekly Arizona miner., 1884-07-04
CONCENTRATION OF ORES.
WRITTEN FOR rHk ARIZONA MINER, BY c If. AARON.
 NuMBER III.

| pecially 30 in the lend ,hake" machines, to slightly raise one of the smaller rollers, between the clear water distributor and the large head roller, by placing bits of wood or leather under the journals. Some mine- rals, among them some varieties of copper pyrites, have the peculiarly that, although when once submerged they remain so, yet they will readily hnst if they have good chance, their surfaces appearing to repel
 water ss do the feathers of a duck. In running an Embrey concentrator on ore containing this kind of stuff, observed that the yellow particles settled well enough onto the belt, and were gradually carried
 beyond the water jets and finally left high and dry. But the water line is not con stant. It alternately advances and recedes as the water is iInpelled by the oscillations of the belt which also advances ard falls back. The yellow sulphurets, once drain ed of water, and apparently in safety, were again invaded by an advancing wavelet upon which they gaily mounted and were carried down stream until, meeting the pelting je,s, a portion of them would te beaten beneath the surface. to repeat more or les. the same performance cd iafnitum,
 while another part sailed, glistening in the sunlight, to eternal perdition in the tail race. This was partly rsmedied by raising one of the rollers as above. Floating par ticles which frequently cover the surface of the water in che heading box may be saved by arranging to withdraw the surplus water from beneath the surface, and sus- peed nlandtter by conveying that water 10 a settling box where 1t will not be agitsteG by the m, ton of the belt.
 It occasionally, though believe not very often, happens that al. ore can be concen- trated to very fair extent by simply crush ing to . certain tineness and sitting. The valuable portion being the more fragile breaks, for the most part, into smaller par ticles than the gspgue. l reeollect an in stance in which tine sifted stutf contained some 150 ounces of silver to the ton, while that which refused the sieve contained about 15 ounces to the ton.
 Concentration by the agency of water tor air) requires good deal of machinery, and where, as Tn Przibram, operations are carried far beyond the mere concentration of the valuable portion of the ore, to the separation of the different minerals, in or der that each may receive it's appropriate metallurgical treatment, a complication of machinery and proc' ssss results which would puzzle an old Hassayampar to get the run Of in any short tune.
 There ia however another system of con- "ns,-'-,->---l ,-rad t, mn. may possibly be utilized here in some casss where the nature of the ore does not adm "f simple method of water concentration;
 that Is concentration by lire, or matte smelting.
 In order that gold and silver may be $, parated from m:ss of rock and earth by the direct agency of fire. it Is necessary that there should be, first, such mix ture as will melt to 2 liquid, and, second, some substa' ce, which, while aisJ b,com- ing ,iquId will remain distinct from the s:a., ai.d will collect within itself all, or nearly all of t',v gold and silver present. This substance may bs lead, copper, iron, pr the sasllphides am arseneides If these m the forms of matte or speiss.
 Where the product is a metal, as lead or copper, the operation is called simply smelt. ng; otherwise tt i- matte smeltiug or con ,entration smelting. In ii her case it is actually cuncentrstis n. more OF lees, of the 'aluable constituents nj the ore in . com
 aratively small hulk and weight. It is an error i, suppose that smelling cannot be ,trried"n without lead, copper or . regular ron ore yielding metallic iron. Instances Ire knosn In which calcareeus silver ore, which coaid not we'll bs roasted for analga- nation uu account of the large proportion ,i lime, was mixed with iron pyrltes and ubjected to concentration smelting, the ,r"duct being an iron matte containing all he silver. The matte was then crushed, pasted with salt. and treated by amaIga- nation or teaching for the silver. In this method of concentration heavy spar IS not Zine can almost entirely be liminated. Pyritous quartz ores, mixed yith os sidized ores carrying lime, clay, etc., nd smelted vill yield matte in which all he copper, silver and geld will be concen- rated Iron pyrites. carrying gold, but not | n sufficient quantity for exportation, may | e enriched by partially roasting, so as to xidixe some uf the iron, and s.sle.tins with
 suitable mixture of quartz lime and clay.
 inc blende may be separated from galena y jigging. Spathie iron has been removed -om an ore by first roasting in such man. CT as to make 1t magnetic, and then pass lg the material through machine which as provided with electro magnets
 The presence If ziDG IS distdgautageous, neither m smelling or in roas,ing for anal ,maiion: yet l have roasted thousands
 tons of ore containing larger proportion
 blende than any have ever seen here; l. owever, when a considerablr -r~~ :..ion of ad is also present. the ross b comes |. oublesome. |. In conclusion. will remark that mining d metaliurey are professions of which but W are masters m all their branches. They ' e difficult professions, requiring years of | perience as we'll as study to enable any t e to practice them with reasonable hope I, success. How it happens that many peo- ,at ores without having learned the busi- a ss, is mystery. No one would think of F tting an excellent shoemaker or a smart :,