Classifying Crushed Ore by Trommels

Abstract

IT was very pleasing to me to read in your valuable publication of November 7, 1895, the favourable criticism written by your correspondent, Mr. T. K. Rose, on my report on the loss of gold in the reduction of auriferous veinstone in Victoria. Nevertheless, permit me to make a few remarks to endeavour to remove a misapprehension under which, it seems to me, that he was labouring, after perusing my report, with regard to the limit to which I suggest volumetric sizing. He seems to think I advocate that the grading of the sand, which has been separated, as far as feasible, from the slimes (which are to be subsequently classified separately in four Spitz-Kästen), should be effected through very fine sieves—60-mesh screens, or under. I quite agree that to attempt to do so would fail. Such, however, is not the meaning, or, I think, the construction which can be placed on the context of my report. A glance at the diagram illustrating the sequence of the methods of reduction, clearly shows, I submit, that it is only the coarser sands issuing from the bottom of the slime separator, that are subjected to “volumetric sizing” in a trommel, which classifies them into three grades, the finest being through a 40-mesh sieve, which is, I apprehend, practically, the most suitable grade for the Frue-vanners to do close work; the overflow from the concentrates flowing into the Spitz-Kästen.