Reference | Title | Date |
RHP146000 | National Coal Board Inspectorate plans of workings | 1957- |
RHP146000/541 | Plans of workings at Ordnance Survey National Grid Reference NS 26/9062 Polkemmet Colliery, Harthill Pit, Polkemmet Pit, East Benhar No.10 and No.13 Pits, Polkemmet No.15 Pit, Simpson's No.4 Pit and Benthead No.2 Pit noted on these plans. | 1956-1970 |