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Major work to remediate the rock slope above Rhigos Mountain Road

Rhigos Mountain Road 1 - Copy

A4061 Rhigos Mountain Road will close from July 22, until the end of October 2024, to safely rectify hillside damage previously caused by a major fire. 

The closure is essential due to the complex nature of working on large areas of rockface, the use of heavy machinery and specialist access equipment to reach the full height of the rockface, and the possible risk of debris falling onto the road.

The fire in summer 2022 damaged a significant area of the mountainside, along with wire netting, plastic netting and fencing. Emergency work that immediately followed the incident enabled the road to open under temporary traffic lights – directing vehicles away from the high-risk areas of rock netting.

Additional emergency repairs to the rock netting were then carried out in autumn 2023 after a detailed inspection of the rock cutting and slopes above, to remove an accumulation of large stones that had fallen from the rockface.

A major scheme to rectify the damage has since been in design. Inspection data has been used to create a model of the slopes, and a simulation of possible rock falls have been used to design a solution that mitigates the risk to road users. The final design proposal incorporates a combination of specialist geotechnical solutions including an attenuator system, rock fall barrier, and active and passive rock netting systems.

The Council is today announcing that the main repair scheme will start on Monday, July 22, and is currently scheduled to conclude by the end of October 2024. A full road closure will be put in place throughout.

The work area is located at the southern end of the A4061 Rhigos Mountain Road, over a length of approximately 375-metres. Alun Griffiths (Contractors) Ltd has been appointed to deliver this scheme on behalf of the Council.

The full road closure is essential due to the complex nature of the work and to mitigate risks to highway users during the work. The road is of limited width and the contractor needs to use specialist access equipment and heavy machinery. Some of the blocks that will be anchored are up to 50 tonnes in weight.

Access for emergency vehicles cannot be maintained, and the Council has consulted the relevant services which have put mitigating measures in place.

The public right of way beneath A4061 Rhigos Mountain Road will remain open for experienced walkers, but this route is not suitable for cyclists.

Rhondda Cynon Taf Council's Director of Highways, Streetcare and Transportation Services, said: “While there will be disruption due to this scheme, planned works seek to minimise this and reduce the risk of sporadic and longer term closures. These complex engineering works are necessary to ensure the safety of this important route, respond to the damage caused by grassfires in 2022, and importantly seek to future-proof the wider structural integrity of this mountain route.

“The works are unable to be carried out either wholly or partially at night, due to the complex nature of the remediation of the rock slope. Daylight hours are essential to provide safe conditions for the workforce to operate heavy machinery and undertake rope access to the large rockface and rock netting.

“The start of the works have been scheduled for the school summer holiday to minimise disruption as much as possible.

“The Council recognises the significant inconvenience this closure will cause for residents of both the Rhondda and Cynon Valleys, but due to the complicated civil engineering that is needed, there are no other viable alternatives available to complete these very necessary works.”

The Council’s Home to School Transport team has been consulted for the period of work beyond September 2024, and alternative arrangements are being put in place with local schools.

Please note, the scheme is scheduled to be completed by the end of October 2024. The road closure notice allows for a longer period of time for the works (up to December 2024) in case of any delays, which is standard practice.

Upon completion of the scheme, the temporary traffic lights which have remained on Rhigos Mountain Road since summer 2022 will be removed.

The Council will work closely with its contractor to make as quick and efficient progress as possible, and updates will be communicated to residents at key milestones. Thanks to road users and local communities for your cooperation.

Posted on 08/07/2024