The arching stone is different to the stone within the mines and quarried on the fell above Nenthead. The quarry still operates today.
Brownley Hill is a vast lead mine, linked to Rampgill up the valley and Haggs Bank mine further down toward Alston.
Surveys say that there are enough reserves of zinc in Brownley Hill to produce 55-60,000 tons of or a year for another 50 years. Moves where made a couple of years ago with the intention of re-opening the mine but I think enviromental considerations made it unpopular with planning authorities.
The river Nent is dead as a result of metal mining in the area and likely to remain so for many years to come, nobody wants to know about the possiblity of re-opening mines there