Name clarification by user Lampwick:

† BMC named it (with a missing S) using the nearest place on the map - Masson Lees Farm.

‡ The name Knowles Quarry is also incorrect. Knowles Mine was (mostly) destroyed by the opencast.

The photo is certainly of Masson Quarry/Opencast with the cavernous entrance to Masson Mine visible. It is likely that some of the Knowles Mine workings were located near this entrance.