SFA, someday I am going to look up the size of Wales compared to Washington State (where I live), because there is so much going on in Wales it seems it must be huge! (Or maybe the history is just piled on top of itself, like the tramways build over mass graves of Black Plague victims of 1666...)
Anyway, I lived on Mt. Baker foothills for twelve years, and hiked all over. if I can import successfully, I found a photo of the Great Excelsior Gold Mine, which caused great greed in 1902 and then petered out...there are better photos I have seen them, and many other mines also. Seems nobody ever got rich though; even the coal, lots of it there but something about it being too pure to be useful!