Abergeldie has recently completed construction of the deepest blind bored vent shaft yet built in Australia. The shaft, bored for a mine in the Southern Coalfields of NSW, reached its target depth of 517m late in 2014.
The 6.2m drilled, 5m finished diameter shaft was blind bored through varying clay and mudstone bands, inter-bedded between very hard sandstone bands in the lower sections of strata.
“We are extremely proud of this latest shaft. Its depth and diameter combined make it the largest shaft Abergeldie or any other Australian company have blind bored,” explains Abergeldie’s Managing Director, Mick Boyle.
“We’re always looking at ways to drill deeper and wider. We design and build all of our own drill rigs and have enhanced them quite considerably over the years to enable larger and deeper shafts to be constructed. In 2009, our deepest shaft to date was 360m deep at 4.25m drilled diameter and our widest drilled diameter was 5.9m at a depth of 260m. To achieve 517m at 6.2m drilled diameter is a credit to our dedicated drilling team and to the design of our rigs,” says Boyle.
“As with every project, this latest shaft has had its challenges. The project team had to develop new methodologies to deal with the specific strata conditions encountered.”
Lining of the shaft took little more than a month, with crews working around the clock to see the 170 composite steel/concrete liners sections – each 3m deep and weighing almost 50t – installed to make a hydrostatically sealed shaft at 5m finished diameter.
Download the free project case study to find out more on how the project was completed.