It was flagged up as a serious concern well in advance of the disaster by the Borough & Waterworks Engineer in his official capacity. Tho was tragically not acted upon.
https://www.nuffield.ox.ac.uk/politics/aberfan/let1.htm
'Mr. T. Ritchie
District Public Works Superintendent.
Reservoir House...
http://www.bbc.co.uk/news/uk-wales-south-east-wales-37689736
I've posted a version of this before on NSC. I make no apology for posting it again.
Today, 21 October 2016, is the 50th anniversary of the Aberfan disaster, when a mountain of coal waste from the nearby coalmine slid down on top of...