By early December, mining contractor Allied Mining had completed 25% of the development work on the Goonyella Exploration Adit for BHP Coal. The GEA is part of the feasibility study investigating the viability of a proposed punch longwall mine at the big Goonyella opencut mine in central Queensland. Work began in August 1999 to assess the viability of establishing an underground mine off an old highwall.
Development of three entries at 30-metre centres using an Eimco Dash 3 continuous miner has averaged 285m per week over a period of ten weeks and is targeting 400m/week. Two of the best shifts recently achieved 60m and 57m.
A few early technical hitches were overcome using a strong engineering and focused management approach, according to Guy Mitchell, BHP manager underground strategy and development. These included problems with the header tank and the scrubbers on the Eimco as well as delivery delays with conveyor equipment.
Allied project and mine manager Frank Fulham said the header tank was "re-engineered to design out overheating problems" which included fitting a bigger tank and changing the pump. Replacement of the scrubbers with South African-made Engart equipment had doubled the scrubber throughput capacity to 10.5m³ per second.
Mitchell said mining conditions had been good and that Allied had exhibited good work practices. The floor, roof and ribs were dry and of a high standard. One of the challenges, according to Fulham, will be proving the success of place changing with 60m pillars in a three heading gateroad layout. A relatively unusual feature of the mine is the use of forcing ventilation to match the place changing method of development.
