This post is part of the GeoConnect³d blog.
Czech Republic is known for the large number of abandoned mines that are a result of extensive and long-lasting mining of a wide range of mineral resources. Celts were the first ones who left their mining footprints in the area; and from the 12th century Bohemia has become one of the centres of gold and silver mining in Europe. The silver coin called “thaler”, the mintage of which started in 1520 in Jáchymov (Joachimsthal in German, hence “joachimsthaler”, in short “thaler”), even gave the name to the current dollar.
At present, the Czech Geological Survey keeps records about more than 26 000 main underground mining objects and old mines irregularly distributed over the whole state territory. Possible reuse of these underground structures represents thus an important aspect of subsurface management processes in the country. In the paragraphs below we describe a few selected examples of reuse of abandoned mines in Czechia.
Underground gas storage
A peak-load natural gas storage with a storage volume of 64 mil. m3 has been built in the abandoned uranium mine Háje in central Bohemia.
Experimental pumped hydro power plant
An experimental pilot underground pumped hydro plant was installed in the abandoned Jeremenko coal mine in Ostrava, ca. 600 m below surface. It was equipped by a 600 kW Pelton turbine and used mine salt water as the medium powering it. The facility was connected to the existing system of pumps keeping a stable level of mine water and utilised two collieries (the upper one with surface retention tank and a tunnel with Pelton turbine and a lower one with retention tank under the turbine).
Radioactive waste repository
A radioactive waste repository is in operation in one section of the underground complex of the former Richard II limestone mine near Litoměřice. So-called institutional waste, which is produced in the healthcare, industry, agriculture and research sectors, has been disposed of here since 1964. The repository also includes a certified test facility for testing of waste containers and special radioactive materials. The total volume of the Richard II mine is over 19,000 m3, the capacity of the disposal chambers is 10,250 m3, of which 70% has been filled to date.
Underground research laboratories
The Bukov Underground Research Facility is located in a former uranium mine in the Vysočina region at a depth of 550 metres below the earth surface and serves as a test site for the Radioactive Waste Repository Authority with respect to the assessment of the behaviour of the rock environment and building materials at a depth corresponding to that anticipated for the future deep geological repository for spent nuclear fuel and radioactive waste. The research and experimental programme carried out at the facility includes:
- Pilot characterisation of rocks for verification of 3D modelling methodology
- Testing of long-term monitoring methods
- Testing of groundwater flow and radionuclide transport models
- Testing of engineered barriers
- Testing of the origin and development of the damaged zone in the vicinity of an underground working
- Testing of technological procedures for the construction of underground workings
- Demonstration experiments
The Josef Regional Underground Research Centre is located in an abandoned gold mine in central Bohemia. The workplace is operated by the Center for Experimental Geotechnics (CEG) of the Faculty of Civil Engineering at the Czech Technical University in Prague. Teaching of bachelor’s and master’s courses focused on underground constructions takes place here, as well as research projects related to research on materials related to the planned deep radioactive waste repository and geothermal energy.
An abandoned gold mine in the Zlaté Hory region has been used for children’s speleotherapy since 1995. The method uses the special microclimate of the underground environment. SANATORIUM EDEL s.r.o. uses a reconstructed part of the mine, which is located 7 km from the hospital. Speleotherapy has become an integral part of the medical operations and stay in Zlaté Hory. 1600 m of underground corridors are used with a maximum depth of 93 m below the earth surface.
The method has a long history, which uses the effect of the underground microclimate on the human body. The microclimate of the underground environment is influenced by the presence of aerosols; other positive properties include:
- Year-round stability of monitored values,
- Constant temperature 7-8 ° C,
- Constant humidity 97-98%,
- Ensured natural air exchange,
- Environment free of microbes, allergens, dusty parts and fungal spores,
- High content of negative ions, absence of ozone and heavy metal ions, low CO2 concentrations, low radiation values.
The speleotherapy facilities are adapted for the stay of children, so they can use a small gym with a playground for volleyball, basketball, table tennis, etc. Of course, there are sanitary facilities, facilities for relaxation and snacks.
Aleš Havlín and Vít Hladík
CGS – Czech Geological Survey
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