When an irregular particle is broken by compres- sion, or crushing, the products fall into two distinct size ranges- coarse particles resulting from the induced tensile failure, and fines from compres- sive failure near the points of loading, or by shear at projections (Figure 5.3). The amount of fines produced can be reduced by minimising the area of loading and this is often done in compressive crushing machines by using corrugated crushing surfaces (Partridge, 1978).