In Welsh history, were the mines owned by English people?

Yes, but the business classes became progressively Anglicised during the 19th century thanks to the tendency for the wealthy to send their sons to English private schools (or 'public schools' as they are confusingly known), so there would have been little difference in cultural outlook between a Welsh mine owner and an Englishman of a similar class.

Remember that speaking Welsh was discouraged even in Wales back then, and a member of a higher socio-economic group would have been keen to be seen as English rather than 'ethnic' so as to fit into polite society.

Many of the mine owners were Welsh - DA Thomas, Lord Rhondda, the owner of the Cambrian Combine company is one such example.

Forget the Follet nonsense - it is fiction, after all. Furthermore, there's a lot of myth about the decline of the Welsh language (the Welsh knot & all). English was the language of global capitalism & commerce/law, etc & as the Welsh coal trade was a global one, so it made sense for the Welsh middle classes to use English. Likewise, if the Welsh working classes were to progress, English was also the language of progress.

Too right Dai bach. Couldn't let the sub-humans own them!