I find myself up in the North East this weekend and am looking for a mine related 3 hour or so surface walk on Sunday. Probably Nenthead area. Any recomendations?
Nenthead round the mill site has plenty to look at and can easily keep you occupied for a few hours. Coldberry and Hudeshope (north of Middleton-in-Teesdale) is another great place in the North Pennine orefield for a walk, though be aware there are uncapped or badly capped shafts up on the tops, or were 15 years ago!
Nenthead itself will occupy your for a while just wandering and wondering. You can also take a walk through the village and head along to Brownley Hill/Gudham Gill (NY77624465), enjoy the mini model village you'll pass on the way to Gudham.
If things don't occupy you for too long, then you can head over to West Allendale and have a short walk around Carrshield/Barneycraig (NY803467). If that doesn't take long enough, then a short drive over the moor into the East Allen and Allenheads itself, or down to Allendale Town and Allen Smelt Mill (NY 8316 5658) - if you drive in from Nenthead along the West Allen valley then you'll pass the Mill Chimneys up on the moor on the way to Allendale Town.