27 October 2021
The cost of mitigating slope safety risk for Welsh coal waste tips
A small failure in a coal waste tip in South Wales. Image from Clear South Wales’ Coal Tips.
In February 2020 Storm Dennis triggered significant instability in a coal waste tip at Tylorstown in South Wales. Whilst mitigation of that problem is now underway, at very substantial cost, it has raised the issue of stability across the large number of coal waste tips across South Wales. Inevitably the underlying concern is a repeat of a major failure, as occurred at Aberfan 55 years ago this month.
Yesterday the Welsh Government published the results of an analysis undertaken in the aftermath of Storm Dennis. This work has comprehensively documented the location of coal waste tips and has provided a first order analysis of their potential to cause risk to safety. The results, which do not make good reading, were discussed at a meeting of the Coal Tip Safety Summit yesterday.
In total 2,456 coal tips have been identified. They have been classified in terms of their safety from A to D, with A representing tips that are minor or have been restored, and D representing those posing the highest risk. The BBC has published a table presenting the results by area:-
In total 327 tips have been classified as C and D and thus need remediation. Many of these coal waste tips are on private land, so the management of the hazard is far from simple. In no case is the risk considered to represent an immediate or imminent threat, but these coal waste tips are now being subjected to increased monitoring.
The Welsh Government has estimated that the cost of mitigating the high risk coal tips is likely to be at least £500 million over the next 15 years, but experience indicates that this will probably rise once the work begins. The issue will become more severe with time unless action is taken as rainfall intensities continue to increase and the waste piles continue to weather.
Meanwhile work will continue to develop techniques to monitor the coal waste tips through the coming winter. Meanwhile, the Twitter account Clear South Wales’ Coal Tips provides interesting commentary on the evolving situation.