Abstract
The physical and mechanical properties of rock can be measured by a variety of standard tests, and studies have shown that there should be a fundamental connection between breakage in comminution and rock ‘strength’. The current study aims to develop the Ring-loaded strength (RLS) disc test, used as an industry standard for the characterisation of brittle ceramics, for determination of comminution behaviour from borehole core samples. The test procedure is simple, reproducible and can yield 250 separate measurements from a 1-metre length of drill core. The 19mm diameter of the test specimens has allowed for the re-coring of explorations drill cores and hence provided additional valuable information.
An examination of the mode of fracture using Thermal Stress Analysis and a high-speed camera has shown that the RLS disc test is tensile in nature and therefore a good indicator of the grinding characteristics of an ore due to the tensile based regimes that are present during comminution processes.
A comparison of the RLS to the Mode I fracture toughness obtained from the Chevron Bend test has shown that a significant positive linear relationship exists between the two parameters. It has been found that the RLS can be used confidently to predict the Mode I fracture toughness across a range of strengths and textures. A similar comparison of the RLS to the Bond Work Index has shown that for fine and medium grained samples where no flaws are present the correlation between the two parameters is highly positive.