A blast design model using the inherent fragmentation of a rock mass

CIM Bulletin, Vol. 83, No. 940, 1990

Brian C. Maynard, Thompson Mine, Inco Limited

Blast design is becoming more and more important as industrial limitations change in regard to economical and physical restraints. Certainly there are ways to alter the nature of the blast by using different explosives, various hole sizes and modifying the timing and charging details. However, it is not possible to alter the fabric of the rock mass. Therefore, it is necessary to learn more about the rock mass and its role in the blast design, and the resulting fragmentation. The major determinant in the degree of fragmentation, or lack of it, is proposed to be the inherent fragmentation of the in situ rock mass. A practical method of quantifying the discontinuities existing in the rock mass is presented and discussed. Likewise, the effects of inherent fragmentation on the resulting muckpile are reviewed. Finally, a fragmentation model combining the calculated inherent fragmentation and the Kuz-ram model is shown using a sample blast.

Mots Clés: Rock mechanics, Blast design, Fragmentation, Modelling, Scanline survey, Kuz-Ram model.