The influence of rock strength and abrasive mineral content on the Cerchar Abrasive Index

The Cerchar abrasive index is based on a simple test and is widely used to assess the abrasiveness of rocks. Detailed examination of the test has shown that the index is largely influenced by the rock strength, and only partially by the rock abrasiveness. The standard test was found to be incapable of providing accurate indices for rocks of low relative abrasiveness and a modification to the test is presented to overcome this problem. The interpretation of the test results has been extended to enable calculation of the specific wear rate which is a more precise measure of the abrasiveness of materials.