By order of Robert Hiecke, ministerial director in the Reich Ministry of Education, a delegation consisting of Ludwig Berg (consultant for museums in the General Section for Art Promotion, Theatre, Museums and Popular Education), Fritz Dworschak (first director of the Kunsthistorisches Museum (KHM) in Vienna), Herbert Seiberl (head of the Institute for Monument Preservation), and Hermann Michel (director of the mineralogy department of the Natural History Museum in Vienna) visited the Lauffen salt mine near Bad Ischl. After Michel had submitted an expert opinion, the mine in Lauffen was approved on 8 November 1944 for the storage of the most important works from Viennese museums. The space in the mine was made available by Gottfried Reimer, deputy head of the "Sonderauftrag Linz" as "all Alpland salt mines [had been] requisitioned for storage by order of the Reich Minister of Finance." Dworschak informed Reimer on 23 November 1944 that he would be visiting frequently in the coming weeks on account of "salvage work in the Ischl salt mine". A restoration workshop was also to be established in Bad Ischl, and the guards and supervisors in the Kaiser Franz Josef Erbstollen were to be housed directly in Lauffen, at Pension Weißes Rössl. At the end of November 1944 Reimer confirmed that the salt mine was ready to store works from Vienna art collections and the Liechtensteinische Gemäldegalerie. The daily reports from Lauffen started on 9 December 1944. The two Kunsthistorisches Museum restorers Josef Hajsinek and Franz Sochor arrived in Bad Ischl in the late afternoon of that day and moved into Pension Engljähringer, which functioned as an office and later as a depot. They were the only members of the salvage team. The first transport arrived on 12 December 1944, although the shafts at this time were not yet cladded for storage of art objects. In the first days of storage, the Kunsthistorisches Museum employed only nine people to transport the artworks into the mine. Further transports, practically all of the stored Viennese collections, gradually arrived in Lauffen. Victor Luithlen, custodian of the Collection of Historic Musical Instruments at the KHM, was appointed depot manager in March 1945 instead of Gert Adriani, who had overlooked items for salvage in a railway carriage and had been dismissed for that reason. Work in the mine was completed on 4 May 1945 and it was closed off. In contrast to the mine in Altaussee, there was never any threat that the artworks in Lauffen would be destroyed by the Nazi authorities.

US troops arrived in Lauffen on 13 May 1945 and took control of the depot. The local manager from the department of Monuments, Fine Arts and Archives was the architect Robert Posey. After access to the mine had been restored, the KHM staff checked the objects stored in the shafts, discovering mould on some of them. A few days later, members of the US armed forces prevented miners from entering the mine and took the two guards Karl Weinisch and Rudolf Denk for questioning to Bad Goisern. Monuments manager Lieutenant Frederick Shrady wanted to transport the objects stored at Pension Engljähringer to the Central Collecting Point in Munich. These items had been set aside for the "Sonderauftrag Linz" and were to have been transported at the end of April 1945 from Altaussee to Lauffen. After the war they were transported to the CCP in Munich. Work in the mine continued. With the aid of supervisors and guards, the restorers Hajsinek and Sochor checked the paintings stored at the station in Tiefbau II. It was not until the end of July 1945 that Victor Luithlen was able to contact Vienna again. He reported on 7 August 1945 to the new First Director of the KHM August Loehr that everything in Lauffen was in order. The objects were returned from Lauffen to Vienna under Luithlen's supervision between 1945 and 1947. Among the few items that were lost was Flowers in a Vase by Jan Brueghel the Elder (inv. no. GG 548). It was later found in a private apartment in Munich and after a long legal dispute was returned in 1959 to the Kunsthistorisches Museum Picture Gallery following a decision by the Federal Court of Justice in Karlsruhe. Seven paintings from the KHM Picture Gallery have still to be found. The former storage rooms now contain a water basin and a store for core drilling.