Salt Lake Tribune | 1905-10-22 | Page 12 | Concerning Concentration

COWCEHNING CONCENTRATION. Combinations of Lead, Zinc and Iron Handled With Difficulty. It Is much easier to enumerate what oreo cannot bo concentrated than those that can, says tho Denver Mining llcnortcr. They axo as follows: Heavy Iron pyrlte, or pyrlto nnd copper, containing no silica, hut which may contain cold and silver: carbonates and plll-cnten plll-cnten of copper, freo from sulphides. Thcso comprise the enllro 111 which are Incnpablo of concentration. All other ores may bn worked either by stralaht concentration or by combination of that and wet extraction. Lad In nny fornv Is extremelr easy to concentrate out from any othor combination of ores nnd cangucx. and, no a rule, fully 30 per cent may bo saved, often more. Hopper In thi-form of black copper or copper plane", or almost any form of tho hlcher oxides. Is easy to save. On tho othiir hand, copper sulphides, especially as chaleopyrtto, aro dlfllcult to save, owing to sliming. All Iron ores except the mixed oxides nnd car-Itonates car-Itonates aro very easily saved. Zinc ores, except ex-cept In heavy combination with Iron or copper, aro easily eonc.-ntrated. Gold Is extremely cosy to save, nnd It Is not unusual to train 0j per cent of Its valuo In tho raw ore. Silver varies, and while oftea tho savhiK will be unall In tho concentrates. It 1st becnuso It exists ex-ists In tho form of chlorldo or somo other llrhl compound In the ore. and this invariably works to perfection by leaching from the talis. The moat dlfllcult of all ores to handle by concentration ar thoso combinations ot lead, zinc, iron, copper. In form of sulptildcs, and piriiaps Inclosed In a gancuc of quartz; lime spar, baryta and gurnet.