A and B Pits were the earliest pits to be sunk at Bournmoor Colliery, 1783 or earlier. On the 1st edition Ordnance Survey map map B Pit is shown as 'old shaft' within an enclosure containing trees, and was by this date clearly long abandoned. During reclamation works on the former Lambton cokeworks site in 2009 the removal of overburden around the 'old shaft' uncovered the remains of the brick lined shaft of the pit. The D shaped boundary marked on the 1862 map was not located - it may have been a fence or low bank. Contemporary records of mine shafts in this period suggest that the pit head structure may have been constructed on a raised mound, which may account for the absence of any structural features in the immediate area of the shaft.