ABSTRACT
The variation of VOD as a function of a borehole diameter is well known. Figure 1 shows its variation with diameter for three common explosives under unconfined conditions. VOD is shown as a ratio of the measured value against ideally calculated value. As expected, ANFO exhibits the largest variation, and even at 200 mm diameter, it has not reached its terminal value. In contrast, emulsion explosive reaches its terminal value at around 150 mm diameter. The data for ‘doped’ emulsion is a variant of Heavy-ANFO, where 10% (by weight) of AN prills.
