Exhibition Tin Mine “Zinngrube” Ehrenfriedersdorf

Gateway to Exhibition Tin Mine at Ehrenfriedersdorfer Sauberg (Source: Freiberg University of Mining and Technology)

Beginning in the thirteenth century, tin, lead, iron, and silver were mined from the mining district Ehrenfriedersdorf. Over 9.75 million tons of ore had been mined here before the year 1990, when active mining concluded due to economic reasons. After the mine decommissioning and flooding processes were completed, a cavity filled with 2.5 million m³ of 10-12 °C water was left, including the mine workings below the deep Sauberger adit. This adit was excavated between 1536 - 1570 and has been draining the Ehrenfriedersdorf mining district as the main water-discharge tunnel since [1]. Today, the accessible parts of the tunnel can be viewed in the exhibition tin mine “Zinngrube.”

 

A very early variation of mine-water usage, a 16-kW geothermal system was installed in the Ehrenfriedersdorf Zinngrube in 1992 in the area of the mine exhibition. Over the course of several development stages between 1992 – 1998, the system was rebuilt and expanded to a capacity of 120kW [2]. This system heats the various visitor spaces of the exhibition mine.

Geothermal mine water system at the Exhibition Mine “Zinngrube” in Ehrenfriedersdorf (Source: Freiberg University of Mining and Technology)

Water-filled cavities can be found at the flood-level of the abandoned tunnel, which were formed due to mining. It is the water that collects here that is used for the geothermal system. From the cavities, the water is pumped to a heat exchanger found at the filling point of the Sauberger main and alignment shafts at a depth of 110m in the exhibition mine.  After the heat is transferred to a closed intermediate heating loop, the water is discharged into an overburden approximately 300 m from the extraction point. The discharge and extraction points are hydraulically connected via the surrounding rock. Therefore, a circulation of the mine water occurs with temperature regeneration. Using a heat pump installed above the surface, the temperature of the water in the intermediate circuit is increased, making the energy stored in the mine water useful for heating applications [2].

Literatur

[1] Hösel G. (1994) Das Zinnerz-Lagerstättengebiet Ehrenfriedersdorf/Erzgebirge. Bergbau in Sachsen, Band 1
[2] Rottluff F. (1998) Neue Wärmepumpenanlage im Besucherbergwerk Zinngrube Ehrenfriedersdorf. Geothermische Energie - Mitteilungsblatt der Geothermischen Vereinigung e. V. 6(21)