Image based modeling of rock fragmentation

Abstract

In the mineral extraction industry, comminution modeling is not only interested in maximum rock strength, but also, or much more, in the energy required to induce rock fracture and, most significantly, into the effect of energy application on the produced rock fragments size distribution. An additional aspect of rock breakage, specific to the mineral extraction industry, is the modeling of liberation of particular mineral grains from the host rock matrix. These aspects of rock behavior make comminution modeling a unique field of rock mechanics.From a traditional engineering point of view (mining and civil), rock samples are considered to be homogenous. Although the mechanical properties of individual minerals can vary significantly, the properties of the minerals and of the mineral boundaries interact randomly enough to assume that in the size of rock samples mechanical properties can be considered homogenous. However, from a comminution point of view, heterogeneity caused by a difference in the properties of minerals are crucial and therefore rock material, even in the scale of a few centimeters, should be considered as heterogeneous. The comminution response of such rock will be influenced by the textural parameters of the rock as well as mechanical properties of constitutive mineral grains.Image based numerical modeling is a useful tool for investigation of the pattern and dynamics of the rock breakage process. Its usefulness rests on the fact that a difficult step of building a faithful model of rock texture and composition, as a pre-requisite for modeling of rock breakage, is removed. Numerical modeling based on the use of classified digital image of the rock surface, could be particularly effective in the mineral extraction industry, where one of the key objectives is liberation of specific minerals, by providing inside view of mechanisms that are responsible for liberation of valuable minerals embedded into specific ore matrix.