Fragment size distribution of in situ rock masses from drill core

The success of rock fragmentation by blasting and subsurface fluid flow depends on many variables, including in-situ fragmentation. This study presents select data from a review of over 13000 feet of core samples drilled at seven different mine properties in the United States and Chile.;Two-dimensional computer simulations of fractures can be used to quantify the volume of rock required to calculate a stable estimate of mean fragment size. Spatial periodicity of fragment size measurements is indicated through vertical variograms and is used as the basis for a statistical analysis for the zoning of rock masses. A more reliable quantitative method to characterize the size distribution of in-situ rock using digital image processing of drill core photographs is also included. Furthermore, a complete experimental analysis is provided for the comparison of currently used correction methods used to develop the full volumetric fragment size distribution curve.