This building is identified by Moses as the Ride Charge Magazine. The `Green Charge' or gunpowder mixture was stored here until required at the Mills. Contemporary photographs show the building to have had a loading/unloading porch and this is shown on the OS 1904 map, but is absent from the 1877 edition. The Nobel Plan describes it as the Steam Engine (No.26 on the Nobel Plan). The existence of a porch makes it unlikely that it housed the steam engine and it may be that this was the original site of the engine, later converted to a magazine. The building has since been demolished, although the footings of a structure are visible on the ground.

References:
Nobel Industries Ltd. (1927) Block Plan of Glyn Neath Black Powder Factory. NMRW
Moses, T.L. Annotated copy of OS 1/2500 (1918). NMRW

D.J.Percival, 18 October 2006