Built in 1938 to store and supply naval mines and munitions ordance to the Royal Navy, at its height during the cold war 400 permanent workers were deployed at the site, housed in an MoD built town infrastructure. The site had an on-site, 2 ft 6 in (762 mm) narrow gauge railway, built using copper to reduce sparks. The weapons were both delivered to the site and then distributed using standard gauge rail to Fishguard, Neyland for Milford Haven, and latterly Pembroke Dock.
Decommissioned in 1992, all 58 cavern storage bunkers and the extensive above ground network of storage sheds and other military buildings remain in place.