A Note on Dawdon Pit

The purpose of the new colliery was to extract undersea reserves which were out of reach of the older, inland Seaham Colliery and to give convenient access to the harbour at Seaham. Over more recent years, however, most of the shipments of coal from Dawdon have been from south Dock, Sunderland. Other markets for the Dawdon output include local power stations and some trade in domestic coal.
The two shafts are each 6.1 metres in diameter and are named Catlereagh (downcast) and Theresa (upcast), the former being 506 metres in depth and the latter 532 metres. The Castlereagh is the service shaft and is used mainly for manriding and materials winding whilst the Theresa Shaft is used for coal winding.
A.F.

In the 1950s, Dawdon Pit was modernised, with electric power taking over from steam, and trunk conveyors bringing coal to bunkers at the shaft bottom in place of the old mine cars or tubs. Longwall extraction was used, both the 'Advance' and 'Retreat' methods. Seams were located at between 800 and 1600 feet below sea level, and extended two-and-a-half miles out to sea. A break in the strata made it difficult to go beyond that.