Work to make coal tip safe after 2020 landside to be completed by winter

Anthony Lewis, local democracy reporter

The latest phase of a plan to make a coal tip safe following a landslide in 2020 is set to be completed this winter with more drainage works planned.

Rhondda Cynon Taf (RCT) Council has released an update on the works happening at the former Llanwonno tip in Tylorstown.

The landslip on the Llanwonno hillside in February, 2020, was triggered by the unprecedented rainfall during Storm Dennis.

It blocked the river valley, broke a foul sewer, covered a water main with several metres of debris and covered a shared footpath.

Current work includes earthworks, transporting the remaining tip material to a receptor site, building infrastructure at receptor areas and work within an extended drainage programme.

Major earthworks

Prichard’s Contracting has used the recent dry weather this spring to restart major earthworks in the existing tip – including removal of the small quantity of remaining tip material to a receptor site.

Meanwhile, good progress is said to have been made with installing infrastructure within the wider receptor area, with all major components built and further activity now under way.

The council said positive progress had been made at receptor site A2 on land to the south of Station Road.

Planning permission was granted in September, 2023, to permanently retain around 740 cubic metres of material from the landslip, and carry out landscaping and ecological mitigation measures on this area of land. Planting work has recently been completed as the final element of this work.

Significant drainage work has been ongoing since phase four got underway.

In the council’s previous update, it was said that more than 1,500 metres of drainage piping had been installed – while the seasonal wet weather provided an opportunity to observe the changes to water movement and springs.

Extra mitigating measures

Because of new factors discovered by the contractor as the work has progressed, including water ingress and changes with the underlying topography, there’s been the need to extend the planned drainage programme to include extra mitigating measures.

The more substantial drainage programme means the overall completion of phase four has been extended to the winter of 2024.

A land management group is being set up to take forward a five-year plan for the area, and work with South Wales Police to prevent off-road vehicles from illegally accessing such sites.

The council also said it remained committed to using the site as part of the Rhondda Fach Active Travel Route in the future, which will establish a surfaced path through the area and include repairs to several nearby bridges.

A four-phase remediation plan has been put in place and included emergency clearance work in the weeks that followed, which was phase one.

Phases two (embankment scour repairs) and three (removal of material from the valley floor to receptor sites and reinstatement of paths) are complete, along with additional work to stabilise the slope.

Work as part of phase four (remediation of the remaining tip on the hillside) got underway during 2023.

Phase four is removing around 195,000 cubic metres of remaining material within the Llanwonno Upper Tip, as well as undertaking major landscaping and drainage works.

The area will be “re-profiled” with 35,000 cubic metres of material used to “smooth out” the landscape. The process will transport around 160,000 cubic metres of material along the disused tramway to the receptor site, located north of what is known as “Old Smokey.”

Welsh Government funding has gone towards the Tylorstown Landslip remediation scheme through the Coal Tips Safety Grant.