ABSTRACT
The usefulness of automated techniques for fragment size-distribution measurements can be greatly enhanced, even considering their present limitations, when combined with precise, predictive, rock blasting models. The currently accepted model for fragment size-distribution may not be valid with respect to the fines content in blasted rock, which represents a significant part of the energy consumed.
Starting with a logical assumption concerning possible fragment shapes of blast-fragmented rock masses, a simple, intuitivelv derived, discretized equation was developed to estimate the new, Total Specific Surface (TSS) -, in: m2/m3 -, generated in rock blasting, using input from fragment size-distribution curves. Equating the specific surface to energy consumption, a cumulative energy — vs — log particle size curve can be drawn.
Using complete, real scale, fragment size-distribution curves down to the silt size, obtained by sieving blast-fragmented, initially relatively massive rock masses; energy distribution curves (cumulative specific surface -vs- fragment size) were generated which indicate that the major part of the explosive energy may be consumed in producing particle sizes smaller than 1 mm. Energy distribution curve-shapes are shown for this real scale, size-distribution curve and for other probable, real scale situations.
