That's right, the Wye is off the coalfield, so the silver (rich) bells would be happy and unworried, whilst the bells of the coalfield just to the south would be doing much worse. At the time the that Idris Davies wrote the words the eastern valleys were undergoing deep economic depression. Other coal mining areas of Wales, including west of Neath(hence the ambiguity) were more properous, because they mined anthracite. men from the Valleys around Merthyr and Rhymney would often travel west to work in the anthracite pits. Cardiff is south of the coalfield, hence their ambigous line. There's also a strand of sadness/loss in his poems about language too- Idris Davies was part of the last generation of mass working class Welsh language culture at the top of the valleys.

Sadly, as I look from my window above Merthyr and watch the heavy machinary ripping the top of the mountain opposite at Ffos Y Fran to get at the coal I am forced to reluctantly say that you could answer the brown bells of Merthyr by saying- 'not much hope for the future, sorry lads'.

If you are interested in the literature of the time and place in south Wales that Idris Davies is part of then there are a couple of writers worth looking out for- Gwyn Thomas and Lewis Jones, both Rhondda men. Some of their books have just been reprinted as part of the excellent Library of Wales. I don't know anything about any writers from north Wales, but the English language literature of industrial south Wales is very rich at the time of Idris Davies. As to conemporary writers there's Rachel Tresize from the Rhondda (is there a theme here?)and a whole bunch of tidy poets including Tony Curtis, Mike Jenkins.

There's some really good history books. Gwyn Alf Williams "When was Wales?" and "The Merthyr Rising" Dai Smith "Aneurin Bevan and the World of south Wales". Hywel Francis and him wrote "The Fed" heavy going but definitive.