DIAMO, state enterprise, branch Stráž

Since 1996, the branch Stráž (formerly branch Těžba a úprava uranu) in Stráž pod Ralskem has been carrying out mining activities – the liquidation of deep and chemical (i.e. underground leaching of uranium through drilling from the surface) uranium mining.

The obliteration of the consequences of deep and chemical uranium mining in the Českolipsko region is the end of more than thirty years of uranium mining, which has significantly affected the landscape in this area through the construction of plants and equipment for mining and processing uranium ore, which has affected groundwater and also affected employment in the region and thus thousands of human lives.

The beginnings of mining development date back to 1962, when several rich uranium deposits were discovered in the area of the present-day Stráž branch in Stráž pod Ralskem and confirmed in the following years. The beginnings of underground mining date back to 1965, when the first pit was dug. The beginnings of chemical mining date back to 1967, when the first leaching experiments were carried out and the first kilograms of uranium concentrate were produced.

Underground and chemical mining reached its peak in the 1970s and early 1980s.

The radical fall in the price of uranium on the open markets in the late 1980s, the slowdown in the construction of nuclear power plants, the cessation of the arms race, the overall loss-making nature of uranium mining and the change in society's view of uranium mining, particularly in terms of environmental damage, led to the cessation and subsequent initiation of the clean-up and rehabilitation of the consequences of deep and chemical uranium mining.

The underground mines have now been safely disposed of, and the surface mine facilities have been demolished, including the mine water decontamination technologies and, for the most part, the chemical treatment plant. Contaminated soils have been removed and the area has been cleaned up. The tailings impoundment is being used as part of the remediation of chemical uranium mining in Stráž pod Ralskem.

At present, the main activity of the branch Stráž is the mitigation of the consequences of chemical uranium mining, which is undoubtedly one of the most extensive ecological burdens in the Czech Republic. The basis is the remediation of the rock environment (mainly groundwater), the disposal of non-operational and unnecessary boreholes and the revitalisation of areas affected by mining activity.

For the purpose of remediation of the rock environment, a complex of unique remediation technologies has been built, which ensure the removal of contaminants from depleted solutions. The extensive solution pumping and operation of the remediation technologies guarantees that there will be no spread of contamination underground in the direction of natural groundwater flow outside the existing remediation area. Mathematical models are used to manage the solution pumping and optimise the remediation process by processing the results of the complete monitoring. In a single year, more than 5.2 million m³ of contaminated solutions are pumped out, more than 3 million m³ of mine water is discharged into a watercourse and up to 150,000 tonnes of contaminants are removed from the rock environment.

The restoration of the area affected by uranium mining is being completed by the revitalisation of the landscape. This includes both surface reclamation and the revitalisation of watercourses. It is a comprehensive treatment of both living and non-living components of the environment. The aim is to integrate the areas affected by uranium mining into the surrounding landscape and to create the conditions for the restoration of natural ecosystems and sustainable use of the landscape.

Restoration ecology plays an indispensable role in this respect. Its essence is to make maximum use of spontaneous or partially controlled vegetation succession to restore human-disturbed sites. This approach is proving to be the most effective in terms of both material and financial resources.

Watercourse revitalisation is aimed at restoring the natural water regime of the landscape. In addition to the revitalisation of small watercourses, other measures are implemented to promote water retention in the landscape and biodiversity, e.g. creation of water pools and wetlands, modification of drainage routes in the form of culverts, etc.

The area of revitalised and recultivated areas in the conditions of the branch Stráž is in the order of hundreds of hectares.

Since 2005 and subsequently from July 2023, the mining and technical burdens from the exploration and mining of uranium, ores and coal in the area of Křižany, Rádlo, the Krkonoše National Park and the Žacléř-Svatoňovice coal basin fall under the Stráž. In all areas, the mine workings have been decommissioned, and the tailings and spoil heaps, if not decontaminated, have been reclaimed either by controlled or spontaneous succession. Buildings and other structures in the surface areas of former mining operations are either demolished and the areas rehabilitated or reconstructed and reused. In the post-mining areas, only monitoring activities are carried out, with possible remediation of the signs of undermining.

For all activities, the branch Stráž uses teams of educated experts. In this respect, it is at a high professional level and has something to offer other organisations dealing with similar issues.