The Mugron military site:
The built heritage of the site was developed by the Kriegsmarine in 1941 in former quarries to house 300 mines in Orin type Schartsmine A as well as underwater grenades. Sainrapt and Brice did the work. The site houses about 70 staff including 40 officers and about 30 infantry soldiers until it was evacuated on August 20, 1944, when the entrances to the galleries jumped.
From May 1943 to January 1944, the feldwebel Heinz Stahlschmidt was assigned to the development depot of the mines transported by submarines the Schartminen A. There he coordinated the technical operations under the orders of the Oberleutnant Alfred kunze and his second officer, The Leutnant Paul Kiessling. Its mines are very sophisticated because they are sensitive to electric fields, acoustics, magnetic field deformation and acidity.
André Jolit, “Dédé la Musique”, head of the Blayais battalion, is the first to enter the quarries by slipping into an air vent. There he discovered large quantities of Perrier’s bottle reserved for the soldiers of the depot.
Defensive, technical and civilian buildings were used to structure the site:

• 5 Tobruk type Bf.58C (model built between winter 1942 and spring 1944), trenches and shooting loopholes arranged in old galleries forming a defensive support point on the top of the cliff.
• An energy shelter: generator, cooling radiator, fuel room and air intakes.
• A sanitary room with showers, toilets and boiler room for soldiers and officers.
• A refectory housing sanitary facilities, kitchens, reserves, housing and in the basement a boiler and its reserve of coal.
  The site was finally neutralized between 28 May and 23 August 1990, when 182 tonnes of explosives were recovered, comprising 124 Type A mines, 17 drifting mines and 44 underwater grenades.