Mohave County miner., 1915-04-10
Successful Oil FlOtatiOn.

concentration of gold ores is only question of time. Already plants have been erected in this connection, and operated (so it is said) successfully. The process has reached the stage where its sphere of usefulness is not confined to the base metals. It must be recognized as a commercially ap- plicable process by gold investigators also, and it is as well now to consider its possibilities. In the first place, being a concentration process, it is of value only where the valuable con- stituents of the ore are in the mineral, or when some refractory mineral is present in an otherwise free-milling ore, and it is desired to remove that mineral subsequent to cyanidation. In this latter connection the Notation pro- cess seems to have an extended field of usefulness in the preliminary concen- tration of cupriferous gold ores. These have been bugbear to metallurgists for many years, not because the cop per interferes with the dissolution of the gold, but because it consumes so much cyanide during the process. A small percentage of chalcopyrite will render the treatment of low-grade gold ore unproftable under existing conditions. The Notation process will remove the copper in the form of a marketable concentrate, and will do it effectively and at small cost. The re- maining pulp will be in fit state to undergo ordinary cyanide treatment. It is doubtful if it will ever pay to float mineral from an ore that yields it's gold readily in an all-sliming process. It must be remembered in this case that the mineral that is slimed in a circulat- ing cyanide solution during crushing will yield it's gold by simple, inexpen- sive agitation. The coarse mineral can be removed, classified, and slimed in the usual manner, and the slimed pro duct mixed again with the rest of the pulp prior to agitation. If the mineral is fioated off, then the same ultimate procedure must be adopted with the Notation portion. The additional eX- pense of Notation will be incurred, as against the cost of agitation and filtra- tion of large proportion of more or less barren tailing. The latter will generally be found the cheapest and less complicated process. When study ing the features of roasting refractory floated concentrate prior to cyanida- tion, it must be remembered that the standard Notation process is practically efficacious in floating mineral slime. As tables do such excellent and cheap work in separating the coarse mineral, it may be said that, as regards gold ores, the chief field for fotation lies in the concentration of refractory slime. It must be borne in mind that the roast ing of slime from a cyanidation stand point is difficult problem, and one that, as far as my information goes, has never been solvel. The process of drying slime leaves Jumps, and these Jumps, however small, will never roast perfectly sweet. There is vast diff ference between a cyanide roast and the roasting of lead and zinc concen- trates prior to smelting. Filter-press- ing and air-drying, followed by disin- tegration of the concentrate prior to roasting, might get over the difficulty. 1 would like, however, to emphasize that it is problem in itself, and to warn investigators that the mere fact of being able successfully to float the valuable mineral in given slime does not indicate that it can be successfully treated unless there is shelter handy to buy the concentrate. In many cases in Western Australia the mineral con- stituents of the ore are so fine, and so intimately mixed with the gangue, that the whole ore must be reduced to a col loidal slime before the mineral is fiber ated. When liberated the mineral in this kind of ore can be readily hoated. Kalgoorlie ore, worth 9.60S per ton, can be readily reduced to 72c., with the