Kepier Colliery, sometimes also referred to as the Florence Pit, was located at the junction of the old Durham to Sunderland road and Kepier Lane, just outside the Belmont Parish boundary. The name 'Florence Pit' probably indicates a link with a colliery by the River Wear known by the same name see here. Pits were sunk in 1818 and 1822, and a Londonderry estates map shows that in 1853 the colliery was linked to both the Gilesgate goods line and to the Sunderland & Durham Railway. The colliery closed in 1872, and because of its residual spoil heap, the site became known locally as 'The Duff Heap', a name which remained in use after its development as a local authority playing field before the Second World War, and which continued to be used after the open space was controversially subject to housing development around 2000.