Radical coal miners? In Villaviciosa? Villaviciosa is just the home to the world famous Spanish cider, sidra
"El Gaitero" - "famosa en el mundo entero", you know ;-D
Mines were further from the coast. If you have the time, I would certainly recommend you to visit the
"Museo de la Miner�a y de la Industria" at El Entrego, like 45 km south of Villaviciosa. It's worth the visit.
Unfortunately, even in that area, there are not so many radical miners nowadays - just before 1986, if I can recall well, some savage closures of mines were done by the government, greatly affecting those mining valleys. Anyway, as you might see in the Museum, as in other places in the surroundings, memories are strongly kept.
With regards to your trip, as most of Northern Spain, you will visit some really nice spots... If you are trying to get to Santiago through the North way (along the coast of the "Mar Cant�brico"), I would only say that, even if have never done my way to Santiago, when I began to think about it some fourteen years ago, that was my first choice :-)
Finally, taking into consideration that it is mainly thought for drivers, and not for hikers, and that you would probably have checked some other sources of information, I would anyway recommend that you visit the
"Gu�a Campsa" web site.