Overview of common processing methods for recovery of indicator minerals from sediment and bedrock in mineral exploration

Abstract

ABSTRACT Over the past two decades, the application of indicator mineral methods to mineral exploration has expanded significantly such that they are now used to explore globally for a broad spectrum of commodities. Indicator mineral suites have been identified for a variety of ore deposit types including diamond, Au, Ni-Cu, PGE, metamorphosed volcanogenic massive sulphide, porphyry Cu, U, Sn and W. Indicator minerals, which include ore, accessory and alteration minerals, are sparse in unconsolidated sediments, thus sediment samples must be concentrated in order to recover and examine them. Because most indicator minerals have a moderate to high specific gravity, processing techniques involving density separation, in combination with sizing and magnetic separation, are used to recover them from sediment samples. This paper reviews the commonly used processing methods including panning, hydroseparation, tabling, Knelson concentrators, spiral concentrators, dense media separators, jigs and various types of magnetic separators, as well as mineral selection and mineral chemistry determinations. Monitoring of quality control is essential at each stage in these processing, picking and analytical procedures. When reporting indicator mineral results, processing methods, fraction weights and size ranges, and laboratory name should all be recorded, in addition to indicator mineral abundance data.