In order to explore uranium mineralization, the Adit No. 1 in the length of 220 m was driven between 1st July 1952 and 1st September 1952, which was a respectable performance in those days. The adit’s crosscut reached the old mine workings on the Johannes Evangelisten silver vein which was then followed by an exploratory drift. The exploration works ended in the mid-1950s. The entire site was directly connected by the fenced corridor with the Svornost mine. Against any escape of prisoners who worked in the adit, solid bars were mounted on the exits to the surface which are still visible in the visitor mine.
The gallery also displays specimens of different types of timbering (wood, steel, bolted), tubs and hand mining tools (drills, drilling hammers) used in uranium mining after World War II.