Caught between a rock and a hard place on Brown Mountain

Two large boulders that blocked the Snowy Mountains Highway west of Bemboka. Photo: Rock Blasting Solutions.

Two large boulders that blocked the Snowy Mountains Highway west of Bemboka have been turned to rubble after a rock-blasting company was brought in to ensure traffic could roll again.

Motorists travelling on the Brown Mountain had been caught between a rock and a hard place when two giant granite rocks fell during heavy rain on Saturday afternoon, blocking both lanes and closing the highway for about 24 hours.

The road was reopened at around 3:30 pm on Sunday, 16 February.

The two boulders, weighing about 40 and 80 tonnes, were blasted by Jindabyne-based drill and blast company Rock Breaking Solutions, which used low impact cartridges to safely break the rocks into manageable pieces.

The job was deemed too risky to complete on Saturday, so crews returned on Sunday to literally have a blast.

The guard rail was heavily damaged by one of the boulders, while the explosion further destroyed it.

The rock-blasting company said it used a pressurised capsule to break stone and concrete. The technique is used in environmentally sensitive areas.

A wheel-mounted, remote-controlled drill rig was used to make a hole in the large granite rock before a low-pressure cartridge was placed inside.

Transport NSW said the remaining debris was transported to one of its existing stockpile sites.

A number of other sites on Brown Mountain were also inspected by geotechnical experts before the road was reopened.

A spokesperson said Transport NSW does regular inspections on the highway at Brown Mountain and is planning a number of slope stabilisation projects in the next three to five years.

The Bega Valley branch of the NSW State Emergency Service has also been working to clear roads across the region.

“The rain has moved huge amounts of sediment, caused scores of new trees to topple and created landslides causing additional damage to infrastructure,” an SES spokesperson said.

“Between the damage caused by bushfires and now flooding rains, some of our amazing south coast landscape will take many years to recover.

“Countless tree arborists, machine operators, truck drivers, labourers, tree assessors, road workers, engineers, field staff and traffic controllers are all working to get things safe for the public.”