The development and application of in-bed compression breakage principles

Traditionally, the liberation of mineral species has been achieved with technologies that rely on indiscriminate size reduction, resulting in products that, because of overgrinding, are not entirely suited to downstream concentration operations such as flotation. A bench-top batch-compression testwork program showed that under certain conditions, in-bed compression breakage could be used to minimise overgrinding and thereby improve flotation recoveries. Based on the principles developed from the laboratory testwork, the Loesche air-swept table-mill was investigated as a means of application on an industrial scale. When compared to the products of conventional mills, the products of the Loesche mill demonstrated a significant improvement in flotation recoveries and grades, particularly for ores in which soft component overgrinding reduces recoveries in conventional circuits.