As they thought the copper mines at Great Orme (what a great place!) was Roman at the earliest it would not surprise me if this gold mine was older too (and the one above that 'orrible power station along the Bala(?) road in North Wales, where the roman road and ampitheatre still exist.)

It seems like yet another case of the establishment not being willing to credit the locals with the ability to mine until the Romans arrived. The archaeos always give the impression that the Romans just arrived and through there superior mining skills identified all the good gold mining spots. What complete nonsense! They would have used local knowledge.