### FM 306: SIZE REDUCTION AND SIEVING

Note that the definition of particle size in Bonds law is different: D80= Particle size such that 80% by weight of the sample is smaller than it. Bonds law is often written in terms of the work index (Wi) as, Where the work index is defined as the energy required per unit mass in kWh/ton to reduce an infinitely large particles to D80 = 100 μm.