During the period May to July 2003, East Mine overcored and recovered from
goaf edges a total of 55 1.8 metre CVX grade bolts to analyse installation
quality. Some 95 per cent of the pneumatically (hand-held Gophers) installed
bolts show gloving, with 75 per cent showing gloving of at least one-third of
the effective bolt length. Hydraulically installed (continuous miner-mounted
bolting rigs) bolts show in some areas less gloving but do have significant
unencapsulation lengths. Trials of newly developed bolt end profiles show
considerable improvements in eliminating gloving but do show variable and
unacceptable variations of unencapsulation.