The Application of Computer Modelling for Blasting and Flow inSublevel Caving Operations

摘要

Many mines have an interest in improving fragmentation at their sublevelrncaving operations in order to produce better ore recovery,lower dilutionrnand less overbreak.The primary requirement for the extraction phase is tornunderstand and optimise the flow of the fragmented rock in the ringsrnincluding interactions with the caved material.Rock fragment formationrnis critically controlled by the blasting phase and can potentially bernimproved by optimising the dynamic energy distribution throughout thernring through the crafting of explosive charging,priming position andrninitiation timing.rnThe modelling of fragmentation and damage due to explosive loadingrnof complete rings is inherently and irrevocably a three dimensionalrnproblem that is difficult to address.We have therefore initially utilised anrnanalytical code to predict vector peak particle velocities and energies thatrnare restricted to the plane of a ring.Dynamic energy distributions basedrnon common timing and priming practice have been compared with otherrnpossibilities using conventional yrotechnic detonators as well asrninitiation designs based on accurate electronic detonators.The energyrndistribution can be quite subtly tailored to increase energy in appropriaternregions or to decrease energy in the brow region for example tornpotentially reduce instability and the probability of misfires.rnWe have also recently developed the capability to efficiently modelrnparticle flow using four-sided polygonal elements.Despite the 2Drnlimitations of such a model this results in more realistic fragmentrninteraction and stacking than can be achieved using conventional rigidrncircular elements.Modelling of a typical sublevel caving ring utilisingrnthese elements activated by the correct dynamics offers considerablernpotential for understanding the influence of the blasting energetics andrntiming on the complex flow and extraction process.