| Show FLOTATION PROCESS PROMISES TO LOWER COST OF MICHIGAN COPPER substantial increases in the recovery of copper in the michigan mining district with a notable reduction in production costs are promised as the result of experimental vork performed by the united states bureau of mines in cooperation with the michigan college of mines and technology which indicates that the 6 ores of that district may be successfully treated by the flotation process the amy b daloia ores which constitute the predominant ores of the district are at present being milled by straight gravity concentration methods with these methods considerable losses of metal have been incurred various attempts have been made in the past to treat these ores by the flotation process but all have resulted in failure some months ago at the request of the mine operators of the michigan Alic higan district A W fahrenwald ore dressing engineer was retained leta ined by the bureau of mines to study the problem in cooperation with the michigan college of mines and technology after experimentation with various combinations of chemical reagents at least one combination has been discovered for successfully floating the ores laboratory experiments have been confirmed by test in one of the largest mills of the district As a result of this research plans are well under way for testing the process in other michigan plants with the expectation that the results should be of great assistance to the michigan copper industry in m the cheapening of costs so as to enable a more profitable operation problem confronting fahrenwald in the michigan district copper occurs almost wholly as native copper the native copper occurs in two 6 general classes of formations viz 6 and conal conglomerate lo 10 me rate 11 n the ores the rel relative active coarseness of the me alic copper and the flaky character of the liberated copper a after ter crushing have been heretofore considered as prevent ln ing the ores es from being amenable to treatment by the flotation process which has been used with remarkable cess in in numerous other metal mining districts of the united states the he study y conducted by mr fahrenwald of the gravity concentration methods now being used disclosed that the gravity tables were not catching catchin 6 all free metallic i copper and that the table middling regrind fegri nd practice was not ashing its purpose the problem was to find the table of reagents capable of floating 6 the primary the e feed which constitutes apar approximately one third of the ore stamped daily on in the district when proper reagent ent combination had been found copper as coa ae as 28 and 35 anesh sh floated quite well and 65 mesh copper m cpr floated readily it als is considered con attained the that large savings may be by substitution 8 of the flotation process for the all gravity proc 38 in ln additional of the lower cost of recovery copper net elt ln concentrate cen and lower slag losses with additional savings from the fact that there is no table middling to regrind with an average additional recovery of two pounds of copper per ton by the flotation method the district would yield without any additional grinding pounds of copper more per year if the daily tonnage of ore be crushed to flotation feed size flotation would give an additional recovery over present practice of roughly pounds of copper per year |
