The Lady Seaham Pit was sunk in 1836 and is shown as active on Ordnance Survey maps of the 1860s and 1890s (1). The maps show a large circular spoil heat with pit buildings to the immediate north-west. The Ordnance Survey map of 1923 shows the pit as 'disused' with the buildings demolished by 1951 (1). The pit was served by a short spur of railway line named the Lady Seaham Branch. In 2013 a geophysical survey of the field containing the pit was conducted (E47350). This revealed numerous ferrous anomalies consistent with the former industrial use (2).