Mining Methods and Machinery · Mining Methods · 2 marks · Numerical answer
Blast fragments have mean-size parameter 60 cm and uniformity index 1.25. Using the Rosin–Rammler form used in the paper, find cumulative mass percent passing a 100 cm grizzly, to two decimals.
Use passing fraction 1−exp[−0.693(x/x̄)^n] with x=100, x̄=60, n=1.25. This gives approximately 1−exp(−1.3124)=0.7308, or 73.08%. The source uses the conventional blast-fragmentation mean-size parameter; it should not be silently substituted for the characteristic size at 63.2% passing.
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