The 1930s saw a number of major disturbances and labour troubles at Taff-Merthyr Colliery, near Bedlinog, due to the problem of company unionism, which threatened to undermine the position of the South Wales Federation of Miners (the Fed). There were a number of violent clashes between members of the Fed and non-unionists or miners who had joined the rival 'scab' or company union. Matters came to a head in October 1934, when 250 members of the Fed were dismissed from the colliery and unemployed miners, who were not members of the Fed, were taken on to replace them. As they made their way to the pit, protected by a large police escort, violent scenes erupted. As many as 300 summonses were issued to people allegedly involved in the 'riots' at the colliery.

Following the punitive sentences received by the protestors there were huge demonstrations around Treharris at which S. O. Davies, Arthur Horner and others spoke. The significance of the disturbances in Bedlinog was summed up by Jim Griffiths in that they 'revealed a new spirit of revolt amongst our people' and 'determination to fight for our economic existence'.

Source:
Merthyr Tydfil Public Libraries, 'The unconquerable spirit: Merthyr Tydfil and District in the 1930s' (1993).