Show ORE DRESSING WORK AT SALT LAKE during the past fiscal year experimental work was continued at the intermountain station of the bureau of mines salt lake city on low grade and complex ores to determine the fineness of grinding oils reagents etc necessary to make the highest recovery of the metals the work consisted of tests by flotation reconstructed oils table concentration roasting and magnetic separation made separately and in conjunction to secure the highest possible recovery and highest grade of product cooperative experimental tests were carried out on various representatives amples of low grade complex silver ores from the park city district utah various tests indicate that by means of flotation 85 to 93 per cent of the silver can be recovered in a marketable concentrate assaying 65 to ounces silver per ton from an ore assaying 7 to 10 ounces silver the ore would have to be crushed to at least minus 80 to mesh size in order to separate the greatest amount of the silver bearin bearing minerals from the gangue angue minerals reconstructed oils gave the best recovery and grades grade of product cooperative experimental work done on a complex lead zinc iron sulphide ore from chloride arizona indicates that this is a very difficult ore to treatie tre treat atin in order to recover a maket able grade of lead concentrate and also a marketable grade of zinc zinc concentrate together with a high recovery of both the lead and zinc the ore must be crushed to at least minus 80 mesh in order to unlock the sulphide minerals from each other and the lime quartz gangue for differential separation of the minerals by flotation the ore dressing work will be continued during the present year |