"Hedleyhill Colliery is worked by the Weardale Iron & Coal Co., and has been in operation about eighteen years. Here the Main Coal seam, 3 feet, the Five Quarter, 2 feet 9 inches, and the Ballarat, 20 inches, are being worked by several drifts. The output, which amounts to 500 tons per day, is nearly all converted into coke, and employment is given to about 500 men and boys. Hedleyhope and East Hedleyhope are collieries worked by Sir. W. Samuelson & Co., at which places similar seams to the above are being worked and large quantities of coke is made."

Whellan's 1894 Directory of County Durham via Durham Mining Museum

NEHL - Hedleyhope Colliery was a fairly large working via a horizontal drift mine just west of the multiple coke ovens. A substantial slag heap stood close to the drift, as well as a few terraces and a colliery smithy. A longer set of terraces built for the workers stood on the road to South Cornsay which are still in situ.