“Rockwheel holds tight Tolerance on Station Box Excavation”

A twin-head Rokla D30 rockwheel is being used for high tolerance rock removal in a station box being excavated during construction of Sydney’s new north-west rail link.

The job involves the removal of 80,000 cubic tonnes of shale material, which is being recycled by one of Sydney’s brickworks. A rock hammer attachment is used to remove coarse material, followed by trimming with the rockwheel to efficiently produce a smooth face to the trench wall that is required to be held within a 40 mm tolerance.

“We use the Rokla rockwheel because of its efficiency in controlled removal of rock from the trench wall. The rockwheel gives us the accuracy we need to hold the specified tolerance, and so far we have achieved excellent results” Long said.

As with any major infrastructure project, timing is of critical importance. In this case there can be no delay in having the site ready for access by a new tunnel boring machine with daily operational costs around $175,000.

Downtime on the rockwheel has been surprisingly minimal: we have only needed to replace two teeth on the twin-head D30 rockwheel attachment which has overcome the challenge of working around many columns, he said.