Improved blasting results with precise initiation

Important results from the project

The project has an industrial and a scientific. The industrial one is to achieve a better fragmentation, throw and other results from blasts in quarries and mines. The scientific one is to show, in the field and with a numerical model, that Rossmaniths hypothesis that the fragmentation becomes best in the areas between the blast holes of the round where the tensile tails that follow directly after the compressive wave front meet, overlap and interact.

Expected long term effects

A successful project provides a validate simulation program for predicting blast results like breakage, fragmentation, throw etc. Quantitative predictions for the effect of initiation delays can not be made today. Electronic detonators, which provide a precise initiation (about 0,1 ms versus normally 6-8 ms) are important as it is only with these that an effective wave superposition may be achieved in practice. Wit a validated simulation program, an optimization of blasting rounds should be possible. This has the potential to improve the fragmentation of blasting rounds and i) the digability in quarries, ii) the internal cracking of fragments in open cast mines, which may raise the throughput in the primary mills at th Aitik mine, and iii) prevent cut-offs and uneven back breakage in SLC rings, which may give a more even ore flow and raise the ore recovery at LKAB. An even breakage and an absence of cut-offs should also give smaller emissions of nitrates from the mines at LKAB

Approach and implementation

Rossmanith has developed a model for three interacting holes and gives time windows for a positive wave interaction. Scientifically this project will improve this result. It will validate and then use a new simulation program (Blo-Up) in order to optimize different types of blasting, e.g. bench blasting as in quarries and in Bolidens Aitik mine and SLC blasting as used by LKAB. Results from such simulations will then be compared with Rossmaniths hypothesis. The project is effected as a prolonged licentiate project with i) calibration calculations, ii) provision of explosives data, iii) simulation of bench blasts plus filed tests with rounds with electronic detonators, iv) simulations of Aitik rounds, v) a licentiate degree, vi) simulations of SLC rounds and vii) testing of the predictions of simple fragmentation formulas.