Blue Mountains slope remediation works

Ventia will deliver much-needed permanent repairs to five slopes along the Bells Line of Road at Mount Tomah, and at two more locations east at Kurrajong Heights, between January and June 2024 (see maps below).

Bells Line of Road will remain open during our work. However, please allow plenty of extra time while crews are working and expect delays. Our work will take place under stop/slow traffic changes with lane closures and a reduced speed limit of 40km/h for worker and road user safety. 

Traffic queues of up to one kilometre may be experienced at times.

The slopes range from 50 to 250 metres in length. Trees and other vegetation have grown into cracks and joints in the road cuttings. This is called ‘root jacking’ and it causes the slopes to become unstable. 

These slopes range from 215 to 300 metres in length. Trees and other vegetation have grown into cracks and joints in the road cuttings, and ‘root jacking’ has caused the slopes to become unstable.

• Using chain saws and woodchippers to carry out vegetation removal
• Using excavators, a telehandler, elevated work platforms and abseiling equipment
• Dislodging loose rocks using hand tools (rakes, picks, shovels and crow bars) and then safely removing this material
• Drilling holes into the rock faces (attached to either an excavator or telehandler)
• Installing rock bolts ranging from three to eight metres in length to stabilise the slopes
• Grouting the rock bolts in place by a crew using rope access and elevated work platforms
• Applying rockfall netting over the rock face and pinning it into position where this is recommended
• Applying steel mesh to rock faces where shotcreting will take place 
• Spraying shotcrete using a truck mounted pump.

• Rock bolts provide active reinforcement to joints within a slope 
• They transfer the load from an unstable exterior to the much stronger interior of the rock mass
• This helps to reduce movement of the rock face.

Above: Example of rock bolt installation used to stabilise slopes at Mt Tomah and Kurrajong Heights.

Shotcrete is a hardwearing material that sometimes provide a better slope stabilisation than soil nails.

Work crews will apply a wet mix of shotcrete to slope faces where this stabilisation method is a better solution. 

Premixed cement will be pumped along high-pressure lines and sprayed at high velocity onto the hard surface and/or steel mesh, increasing overall strength of the slope surface. 

Shotcreting avoids the need for costly formwork and reduces waste as we can carefully control the application of the concrete.

To ensure motorist safety, we need to remove more than 100 trees across the Kurrajong Heights sites. An estimated 16 trees will need to be removed from the Mount Tomah sites. 

This is to stop the ‘root jacking’, where trees and other vegetation grow into cracks and joints in the road cuttings and cause the slopes to become unstable. 

The tree clearing will include up to one metre behind the crest of each slope.

Transport and its contractors are committed to replanting more trees than must be removed.  We are developing a landscape design which will be implemented once all stabilisation work is completed. We will ensure that native species are used in both areas.

Transport and its contractors are committed to minimising and mitigating environmental impacts. This can include: 

• Identifying clearance limits to minimise native vegetation removal
• Holding pre-clearing inspections by ecologists
• Replacing and relocating habitat 
• Using biodiversity offsets to address tree and hollow removal, after the full extent of local impacts have been calculated.

• April 2024 - Slope remediation work on Bells Line of Road, near Mt Tomah from Monday 22 April 2024 (PDF, 200.29 KB) 
• April 2024 - Slope remediation work on Bells Line of Road, near Kurrajong Heights from Monday 15 April 2024 (PDF, 197 KB)

• April 2024 - Slope remediation work on Bells Line of Road, near Kurrajong Heights from Monday 15 April 2024 (PDF, 197 KB)

• April 2024 - Slope remediation work on Bells Line of Road, near Mt Tomah from Monday 22 April 2024 (PDF, 200.29 KB) 

Community updates will be uploaded here as they become available.

FAQs will be uploaded here as they become available.

Review of Environmental Factor (REF) documents will be uploaded here as they become available.

• March 2024 - Mammoth project to improve resilience along key western road corridors