Evolution of Block Size Distribution within a Draw Column during Block Cave Mining
First Presented:Cave Mining Forum - Workshop II
This presentation will cover the evolution of block size distribution (BSD) within a draw column during block cave mining. BSD plays an important role in controlling gravitational flow, secondary fragmentation, and fines migration in broken ore—all of which are fundamental in preparing a reliable feasibility assessment for a potential caving operation. However, there is a marked lack of procedures for assessing secondary fragmentation and its influence on BSD, especially at the pre-feasibility level. Recent efforts have focused on the use of advanced numerical modelling, for which the level of detail required is suitable for advanced feasibility and mine design stages. A simple-to-use, empirical method for estimating BSD has been developed based on laboratory and field data reported in the literature. The method accounts for a combination of secondary fragmentation processes and fines migration under both isolated and interactive flow. The model is tested against field data from the El Teniente mine in Chile to calibrate it and determine its limitations. The resulting procedure provides an improved means of assessing secondary fragmentation and hang-up potential for pre-feasibility and feasibility level studies of large block caving projects.
This presentation summarizes a talk given during the second workshop of the Cave Mining Forum.