Show ADVANCES IN concentration the prosperity of the mining industry depends ds largely on the possibility of treating large tonnages ton nages of low grade ore the bonanza mines are an important factor and their production by their fabulous richness aids in attracting attention to the industry and makes men more willing to risk their capital in mine development but it is upon the low grade ores that real success is based the importance of the so called porphyry coppers need not be emphasized here it is here it is well known however looked at from the technical and scientific side the concentration of these ores is not an unqualified success losses are heavy and extraction low As an evidence of the desire I 1 to advance along this line is the increasing search for cheaper and more efficient methods of concentration the use of flotation principles for the recovery of sulphides sulp hides from low grade ores is well advanced abroad especially in australia and it is only a question of time when it will become as familiar in this country as it has abroad flotation is just be beginning inning to get ge t deserved attention here merely a recital of what is being done emphasizes this point in arizona the inspiration has in process of construction a ton flotation plant built as a result or of highly successful preliminary tests indicating a great increase in extraction at as low or lower cost than gravity methods the nevada consolidated in nevada plans a ton plant and tests are to be undertaken at the mill of the ohio copper company on bingham ores we understand der stand that utah copper is also making extensive tests these are ahre only a few of the activities in zinc ores to which the process is especially applicable the butte and superior at butte has a mill of large capacity which is using flotation methods with higher extraction than could be obtained in any other way not only are the low grade sulphide ore of copper and zinc being now treated and tested but the concentration or more properly reduction of oxide ores by methods now little used in the united states is being advanced oxide ores are fit subjects for leaching for many years the shannon and other companies in arizona have leached beached their ores successfully among those now testing out leaching methods are the anaconda copper co at anaconda montana and the nevada douglas at ludwig nevada the and butte and duluth at butte have leaching plants in successful operation and claim great efficiency fici ency eney at very low cost the nevada douglas will treat ore while the anaconda plans to leach its tailings by a method which we hope to give in some detail at an early date construction of the plant at anaconda is well under way A very few years should see these two methods displacing many of the gravity methods now used for the low grade ores both ideas are old but have only be been en n extensively ten practiced abroad bids fair to revolutionize the milling of porphyry ores while leaching should make a much larger portion of our known low grade cop j per ore treatable at a profit which will i maintain the copper supply at a high level for a long time to come |