Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 149,260 pages of information and 234,236 images on early companies, their products and the people who designed and built them.
of Seaham Harbour
1819 The Londonderry family became coal owners through the marriage in 1819 of the third Marquess of Londonderry with Lady Frances Anne Vane-Tempest, a descendant of the Vanes of Longnewton and the Tempests of Wynyard. The Tempest family owned a number of collieries around the city of Durham.
Under the third Marquess and his wife, these collieries were developed.
1821 The Seaham estate was purchased; Lord Londonderry laid down a railway from Rainton to Seaham, with branches to all the collieries in which he was interested, and constructed a dock at Seaham.
1899 The company was registered on 31 May, to acquire various collieries in the County of Durham. 
c.1927 A new pit was being sunk.