The Swebrec© function: linking fragmentation by blasting and crushing

Abstract

A new three-parameter fragment size distribution function has been found that links rock fragmentation by blasting and crushing. The new Swebrec© function gives excellent fits to hundreds of sets of sieved fragmentation data with correlation coefficients of 0·997 or better (r²>0·995) over a range of fragment sizes of 2–3 orders of magnitude. A five-parameter version reproduces sieved fragmentation curves all the way into the –100 μm range and also handles ball mill grinding data. In addition, the Swebrec© function: (i) can be used in the Kuz–Ram model and removes two of its drawbacks – the poor predictive capacity in the fines range and the upper limit cut-off to block sizes; (ii) reduces the JKMRC one-family description of crusher breakage functions based on the t₁₀ concept to a minimum; and (iii) establishes a new family of natural breakage characteristic (NBC) functions with a realistic shape that connects blast fragmentation and mechanical comminution and offers new insight into the working of the Steiner's OCS sub-circuits of mechanical comminution. It is suggested that the extended Kuz–Ram model, with the Swebrec© function replacing the Rosin–Rammler function, be called the KCO model.