Reference | Title | Date |
RHP146000 | National Coal Board Inspectorate plans of workings | 1957- |
RHP146000/542 | Plans of workings at Ordnance Survey National Grid Reference NS 26/9063 Benhar No.22 and No.23 Pits, Polkemmet Colliery and Harthill bore noted on these plans. | 1956-1961 |