According to Merfyn Jones' "the North Wales Quarrymen 1874 - 1922"...
"Little is known about the quarryman's wife and daughter ... Slate quarrying was a male industry and as far as is known no woman worked in a slate quarry in any capacity, certainly not after the early period of capitalisation and development of the industry..."
Is this true? If so, why is it so different to quarrying, and mining - including of slate - in other areas of Britain? We've been doing a bit of research, and the results are surprising!