Blind boring of a 465 meter deep, vertical shaft for ventilation of and access to Austar’s Stage 3 underground workings at their Hunter Valley coal mine. With an on-site fabricated, composite steel and concrete hydrostatic liner, the shaft has a finished diameter of 4.5 meters.
Construction required a high level of accuracy. The challenge was to maintain true verticality throughout the entire depth, to within 250mm of its centerline to eliminate complications when transporting workers and materials through the shaft. There was an allowable tolerance of 0.05 per cent for the entire shaft length. A directional pilot hole was drilled for the drill head to follow.
Austar Coal Mine Pty Ltd