Now as part of the North Pennines AONB Partnership's Living North Pennines project funded by the Heritage Lottery Fund, contractors are on hand to lear the sites of vegetation and consolidate unstable sections of stonework. It is hoped that the sites will be repaired to the point where visitors can enter them again.
The other sites being repaired are mines in Cumbia and an engine house in Northumberland. All are currently included on English Heritage's At Risk Register.
Jon Charlton of the AONB Partnership said: "These buildings taken together really tell the story of the North Pennines, how our ancestors down the ages lived and worked in the area. Over time they would have crumbled and disappeared completely; we want to protect what remains so that we and future generations can see these legacies in the landscape of what it was like to live those past lives. We are extremely proud to be working with the Heritage Lottery Fund and English Heritage to help the building owners save these irreplaceable pieces of heritage."
Archaeologists are expecting to uncover some fascinating new insights into the ways the buildings were used and their significance in the wider context.
Paul Frodsham, Historic Environment Officer with the AONB Partnership said: "The North Pennines landscape is renowned for its lead mining heritage, and while the remnants of the lead industry are important, the AONB's historic environment consists of much, much more. The 13th Century remains of Muggleswick Grange, for example, are a really important historical link between the North Pennines and Durham Cathedral. Archaeological investigations are being undertaken in association with consolidation work at Shildon, Muggleswick, Ninebanks and Whitesyke, and this will add substantially to our understanding of North Pennines history."
Muggleswick Grange, near Consett, was built during the mid-1200s for the Prior of Durham and originally lay in the grounds of an enclosed park. It is considered of national importance because standing remains of monastic granges from this time are very unusual.
The sandstone Ninebanks Tower is all that remains above ground of a large medieval house, to which the tower was added in about 1520.