Show concentration and ore dressing says the denver mining reporter are terms quite distinct in their meanings the term concentration cent ration is rightly applied when it refers to the enrichment of a grade of ore too low in value to pay mining hauling and smelting smelling sm elting charges the worthless material tailings P is much greater in weight than the valuable material or concentrates usually the ratio of weight in the west is three of tailings to one of concentrates the concentrates being enriched from about two to three times the value of the crude ore will bear all expenses and leave a profit an example is the concentration of the tailings leaving the plates in a stamp mill the term ore dressing t implies the separation of valuable minerals one from the other so as to leave each product in a marketable condition an example may be given of the separation of zinc and lead ores mixed the ores are of no value but when separated into two products zinc blende and galena each is valuable for itself although the mixed ore is of no market value leadville ores may be cited As mined they may be of no value commercially though carrying t intrinsic values of 20 or more the local smelters shelters sm elters will not buy them because they carry too much zinc and the zinc smelters shelters sm elters do not want them because they carry too much lead when the zinc and lead minerals are separated then each becomes valuable and this separation is ore dressing and not concentration cent ration |