The Svornost mining pit represents an integral part of the Jáchymov spa. This is the place where the radon waters are collected and then brought to the spa-facilities down town.
The Svornost pit, established almost in the same time as the town itself (in 1518), bears its present name, meaning concord (Einigkeit in German), since 1530. Thus it is the oldest mining pit still in operation not only in Czech Republic but perhaps also in the entire Europe.
In the course of 16th century the Svornost pit was used for silver mining. Since the middle of the nineteenth century uranium ore mining became the main resource being mined here. The boom of uranium mining started after 1945 and lasted until 1962 when, due to the depletion of the uranium deposits, the mining activities were gradually terminated. In the beginning of 20th century it was discovered that some of the water springs collected deep underground show a high radon content and that they have a positive effect on healing wounds and can improve certain medical conditions. Based on this founding first radon spa-house was established in 1906 consisting of two bathtubs in the house No. 282. Water from the so-called „Štěpové Springs„ collected on the Daniel floor of the Rovnost mining pit was used for the bath treatment there. At first the water was transported down to the spa-house in buckets or by a team of horses. Since 1908 the water was brought down by a pipeline to bath cabins made in a former uranium processing plant, since 1911 to bath tubs in a newly built Spa Building (Lázeňská budova). However the capacity of the Štěpové Springs became insufficient by the twenties of last century. A decision was made to use the powerful spring of the radon water hit in 1864 while deepening in the Svornost pit from the 12th to the 14th floor, which flooded the Svornost pit from the 12th floor up to the Daniel floor. For this purpose, in 1924, the flooded premises of the pit were drained, the entire pit was restored and the basic technical objects for collecting and pumping the water were installed. In memory of Marie Curie’s visit in the Svornost pit in 1925 the spring received its name - Curie. This spring was the main source of the radon water covering the needs of the spa treatment until the beginning of sixties when the uranium mining ended.
In the same time (early 60s), relative to the planned future development of spa practice it was decided that the Svornost mine, comprising the Svornost and Josef pits, shall be used for collecting and drawing radon water even after the termination of the mining activity. For this purpose necessary support work was performed there in 1962-64 such as the construction of pressure levees separating the Svornost pit from the remaining of the deposit, which was to be flooded. At the same time an extensive geologic survey was made discovering another two springs of the radon water on the 12th floor of the Svornost pit, the C1 Spring in 1960 and the Běhounek Spring in 1962. The Svornost pit was transferred to the Jáchymov State Spas organisation on 1st April 1964 after all the support works and surveys were finished.
During the past forty years, extensive restorations of the Josef Pit (1983-87) and the Svornost Pit (1992-96) have been carried out. In year 2000 a new spring, called Agricola, was drilled. Recently there are 4 springs being used on the 12th floor of the Svornost mine in the depth of 500 meters under the surface. They are as follows:
Water form these springs is collected into a basin on the 12th floor and from there it is pumped about 400 m higher to the collector basin on the Barbora floor. The water is then gravity flowing from this basin to the Daniel floor and from there it is distributed by pipelines in the overall length of 3,000 meters to the individual spa-facilities. To provide the best quality of the radon water 2,700 meters of new pipe were laid underground in 2001.