Merthyr Tydfil Borough Council (MTBC) had raised fears about the safety of the Aberfan tip complex since it was begun. Notably, a series of letters passed between the Council and the National Coal Board entitled 'Danger from Coal Slurry being tipped at the rear of the Pantglas Schools'. Copies of this correspondence are in class D of the Dowlais collection of the Aberfan Disaster archive. The letters containing the most clearly worded warnings are reproduced here. Although nothing on the scale of the disaster was ever envisaged, the correspondence still represented a significant warning that went largely unheeded.
Example One
MTBC Borough & Waterworks Engineer to District Public Works
Superintendent
24 July 1963
Example Two
MTBC Borough & Waterworks Engineer to NCB Area Chief Mechanical
Engineer
20 August 1963
Example Three
Area Mechanical Engineer, NCB to MTBC Town Clerk
28 January 1964
Example Four
Area Mechanical Engineer, NCB to MTBC Borough & Waterworks
Engineer
13 March 1964