Ballarat Goldfields NL is developing an exploration decline at Ballarat
East using a Mitsui Miike S-125 roadheader. To-date, 530 in of advance
has been achieved at an average rate of 16.1 m/week. Roadheader
availability has averaged 94.3 per cent, and pick consumption has
averaged 0.016 per m. Ground support has involved pattern rockbolting
with split sets, 100 mm thick fibre reinforced shotcrete, and steel sets as
required. The slower than expected advance rate has mainly been due to
difficult ground conditions. It is expected that a further 970 in of decline
will be mechanically excavated before a drill and blast system becomes
more economical.