Tests to determine the abrasiveness of rock
Although abrasiveness is a generally used word and certain rock types are described as abrasive, the implication is not straightforward. The common approach to date to assess abrasiveness of rock is by performing tests on the rock material and measure the wear of the tool material used in the test. The mineral hardness is determined by proportional summation of the Mohs Hardness of the abrasive minerals in the rock. J. Schimazek and H. Knatz determine the average grain size using Rosiwal's line intercept method, by measuring the number of intersections of grain boundaries along parallel measuring lines laid over a thin section studied by microscope. The hardness test and the abrasiveness test were used to examine the workability of the rocks with respect to machine excavation. It became clear that standard tests had important limitations, making them of limited use for purposes of prediction of wear of cutting chisels of rock excavation machines.