Current developments in theoretical calculations of stress distribution within the resin encapsulating roof bolts in underground mines are presented. Monitoring of steel bolt performance indicate that, amongst many parameters, bolt profile plays an important role in load transfer between the bolt and the surrounding strata. To optimise the bolt profile geometry a better understanding of the failure mechanisms, that occur within the resin and bolt interaction, must be achieved. The short encapsulation pull out tests of roof bolts with various surface profile geometry indicate a significant variation in peak bolt performance. Both profile height and spacing have been found to affect the load transfer mechanism of bolts (Aziz et al., 2003，2008). In particular, and as shown in Figure 1, wider spacing of 37.5 mm bolt was found to be the most effective profile in bolt resin encapsulation interaction when compared with similar height profile bolts of different spacing of 12.5 mm, and 50 mm bolts respectively.
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