From my private research about my home in World War II:
Planned underground relocation in Himmelsberg near Woffleben to expand the Mittelwerk-Dora V-weapon production facility; conceived with 100,000 sqm / but in February 1945 Henschel Flugzeugwerk AG = Flugzeugwerke Schönefeld AG & Oder AG (Siemens & Henschel) received the tunnels for the construction of the Hs rockets 117 (butterfly) and 298 (typhoon), at the beginning of March 1945 it should 5,500 square meters were in use to mass-produce the anti-aircraft missile Hs 117 ("Butterfly") with a need of 1,100 people. [Note: Under the direction of Professor Herbert Wagner (was involved in the development of all Hs rocket types), a development station and a production facility for rockets were to be built in Himmelsberg]
A newly developed drilling rig was used for the tunnel construction, which was developed in the pioneer training battalion in Höxter on the Weser / the stone excavation from the tunnel construction was brought to a tip with trains, which is about 3 km from the construction site next to a plastering factory lay (cley singing); for this purpose, a siding from B-3a ran directly to the Nordhausen-Northeim railway line / here a sub-command of III worked from 01.06.1944 - 15.01.1945. SS construction brigade from Wieda; the management staff was based in the Bischofferode manor.
All internals, the machinery and the rocket parts were removed by the Allies from the tunnel system immediately after the end of the Second World War. The Soviet troops removed the rest just before the explosions; the tunnel system should no longer be used for armaments purposes.