Forgot to say that the words sung by Oceans Apart are as Joe Offer and Susanne have posted as far as I can tell.
Posts on this thread provide information on Frank Hennessy. What is known about Noel McLoughlin?
To what does the "muffler and the cap" in the line "Farewell you colliery workers, the muffler and the cap" refer? Were temperatures in the mines so cold that all miners wore mufflers and caps while working?
I'm no linguist, but my understanding is that the double d (dd) in Welsh is prounounced as "th". The unidentified poster above who gives the pronunciation guide for Ystrad Rhondda as "Ushh-trad Ron-the" which is the way John Good pronounces it on the CD. Why then is the name of the valley prounounced "Rhon-da" in the chorus and the song title? (Duh! I guess I should just ask John the next time I see him. He speaks fluent Welsh.)