RCT Council has provided an update on Phase Four work to remediate the Tylorstown Landslip site. The majority of the colliery spoil has been moved to the receptor site, with good progress made to develop drainage infrastructure.
The landslip on the Llanwonno hillside in February 2020 followed three storms in succession – and was triggered by the unprecedented rainfall during Storm Dennis. The landslip blocked the river valley, broke a foul sewer, covered a water main with several metres of debris, and covered a shared footpath. The Council has implemented a four-phase remediation plan for the site, with Phase One including emergency clearance work in the weeks that followed.
Phases Two (embankment scour repairs) and Three (removal of material from the valley floor to receptor sites and reinstatement of paths) were completed in June 2021, followed by additional work in autumn 2021 to stabilise the slope. Final works for the permanent use of the receptor sites will be developed and implemented in due course.
Planning permission for Phase Four (remediation of the remaining tip on the hillside) was granted in October 2022 and got underway in April 2023.
Phase Four works will remove around 195,000m3 of remaining material within the Llanwonno Upper Tip – including drainage and landscaping works. The area will be re-profiled with 35,000m3 of this material used to ‘smooth out’ the landscape. The process will transport around 160,000m3 of material along the disused tramway to the receptor site, located just north of ‘Old Smokey’.
Latest progress update – early November 2023
Ongoing site activity by Prichard’s Contracting has continued well in recent months. Most of the spoil material has been relocated from the hillside to the receptor site – with some very localised changes taking place as the weather and water conditions allow. As the spoil material is removed, the design team and contractor are closely reviewing the ground conditions being revealed, as part of an ongoing review of the final profiles of the hillside to ensure the most stable outcome.
Progress to install the significant drainage infrastructure has also continued – with more than 1,500-metres of drainage piping installed to date. The wet weather in recent weeks has been challenging in terms of relocating the spoil material – but it has provided an opportunity to observe the changes to water movement and springs, as they develop to the hillside’s new profile. The site will continue to be observed and managed over the winter period.
Creation of the receptor site has progressed well recently, with two attenuation basins now completed and operational – with the third nearing completion. The basins will manage the water run-off into the pre-existing drainage channels, during periods of wet weather.
Work related to Phase Four of the remediation plan is still on course to be substantially completed on schedule, by the end of 2023. However, there will be some remaining works that need to be continued into 2024 – the extent of these will depend upon the weather in the weeks to come.
Away from the site, the Council is working to progress the longer-term land management plan for the hillside, including ways to prevent access by off-road vehicles. Alongside South Wales Police, the Council will raise awareness of the damage that can be caused to such sites by scramblers.
Councillor Andrew Morgan OBE, Leader of Rhondda Cynon Taf Council and Cabinet Member for Infrastructure and Investment, said: “There continues to be lots of activity at the Tylorstown Landslip works site, as the significant Phase Four operation to remediate the remaining tip on the hillside progresses towards completion. The latest drone images show the vast scale of the task at hand, and also the good progress that has been made in recent months to transport thousands of tonnes of spoil material to the receptor site.
“Positive progress has also been made to develop the drainage infrastructure on the hillside, and to establish two of the three attenuation ponds at the receptor site to control the flow of water to existing drainage channels. While we’ve seen persistently wet weather in recent weeks, making progress more difficult, Phase Four is still on course to be substantially complete by the end of 2023.
“The Council continues to welcome Welsh Government funding support for this scheme through the Coal Tips Safety Grant, while important work is also taking place behind the scenes – such as establishing a Land Management Group to take forward a five-year plan for the site. Meanwhile, in consideration of the wider role of managing colliery and quarry spoil tips, our recruitment to the Rhondda Cynon Taf Tips Safety Team is also being continued.”