A study prepared by Dr. Natalija Špeh, Klemen Kotnik, and Dr. Irena Mrak from the Faculty of Environmental Protection in Velenje, examines areas degraded by coal mining and energy production (hereinafter referred to as DOPE).
Degraded areas represent one of the key spatial and environmental challenges in regions where land use has been shaped by intensive industrial activities for decades. These are areas where the practical value of the land has been so diminished by past interventions that mere minor repairs are insufficient for their revitalization; rather, comprehensive remediation and development measures are required. Degradation can manifest as physical, ecological, or functional deterioration of the land, and is often associated with abandoned, underutilized, or environmentally degraded land use.
In legislation, degraded areas are distinguished from devalued areas, as the former are primarily associated with environmental pressures, while the latter are characterized by a decline in the economic, social, or visual value of the area due to inappropriate or abandoned use. In this study, we focus on degraded areas that have resulted from many years of coal mining and energy production in the Savinja–Šaleška region (DOPE). Understanding these areas is crucial for planning future spatial development, restructuring the region, and identifying new opportunities for the sustainable use of these areas.
The study begins by compiling European legislation in the areas under consideration: the “polluter pays” principle, the Green Deal, a just transition, phasing out coal, and nature restoration.
The following is a set of methodologies for identifying degraded areas, which includes:
Functionally degraded areas (FDO), which were renamed functionally devalued areas (FRO) at the suggestion of the municipalities (2023); there are a total of 24 such locations in the SAŠA region.
Potentially Contaminated Areas (POO); a study of the levels of environmental sensitivity and risks to human health in the event of potential contamination identified 11 sites in the SAŠA region (2022).
Degraded Urban Areas (DUO); this is a pilot test of the FDO methodology in urban municipalities (2020); 19 locations in the SAŠA region.
The SPIRIT study; similar to Methodologies 2 and 4, it is derived from the FDO methodology.
An example from abroad is included—that of the UK Environment Agency—where degraded areas associated with coal mining are assessed as part of the Contaminated Land Risk Assessment (CLR). A cartographic representation is included, separately for each methodology for degraded areas in the SAŠA region (with accompanying data files).
While regional data for the Upper Savinja Valley show no impact from coal mining and energy activities, we have broken them down as follows for the Šaleška Valley:
- direct impacts: coal mining infrastructure, land subsidence and odors, ventilation, etc., and
- indirect impacts resulting from activities that are strictly necessary for coal mining (impacts on residents, geotechnical impacts, changes in hydrological conditions, and operations at the Paka Quarry).
The following are the results of the analysis of spatial data—both publicly available data and data from the Velenje Coal Mine’s technical documentation—presented with graphical representations:
- Changes in the area of the PV extraction zone (PP) over time/across 3 periods, based on the update to the PV Concession Agreement (354-14-73/1); (Figure 5).
- A remote sensing method based on the analysis of time series of digital orthophotos of the PP PV surface from 1972 to 2022 (Figures 7–15);
- We have illustrated surface subsidence—the most obvious consequence of underground mining—using weighted values and indicators (presented in Section 4.2) and in the following categories: 1 = impact area (IA); 2 = mining area (MA) of the coal mine without an IA; 3 = southern mining area (MA) and 4. Pesje area (Table 3, Figure 6):
- We consider the maximum surface subsidence limit ( <, and 1 cm subsidence), projected upon completion of lignite mining in 2033, together with the projected volume of excavated material (12.24 million metric tons); identical to the VO limit.
- A presentation of changes in the volume, surface area, and depth of the Šaleška Lakes (in 1984, 1994, 2004, 2014, and 2024), as well as the projected state with isobaths for 2024, including forecasts for 2030 and 2040 (Figures 16–20a–c);
- An overview of infrastructure facilities within areas (1–4), which are classified according to the categories listed in section 3 above (Table 6);24-hour odor measurements were commissioned for the Šoštanj municipality area, once (October 21, 2024).
The Šoštanj Thermal Power Plant (TEŠ) has had a significant impact on the environment in the past, but today these impacts are considerably smaller. The production of electricity from lignite has caused pollution of the air, water, and soil, particularly due to air emissions, ash transport into Lake Velenje, water withdrawal from Lake Družmirje, impacts on the microclimate, and increased noise. Above all, SO₂ emissions—which in some places exceeded 100,000 metric tons annually in the 1980s and accounted for approximately half of Slovenia’s total emissions—posed the greatest environmental problem.
With the introduction of a comprehensive environmental remediation program—particularly following the adoption of the TEŠ Environmental Remediation Program in 1987—emissions and pollutant concentrations have been significantly reduced and are now mostly below legal limits. A major step forward was the establishment of a closed-loop ash transport system in 1994, which improved the condition of Lake Velenje and the Paka River. Further environmental improvements were achieved with the construction of Unit 6 (trial operation in June 2015). Based on measurements of air quality, precipitation, and water bodies, the current state of the environment does not provide a sound basis for identifying degraded areas resulting from the operation of TEŠ.
The documentation (PV Concession, Mining Technical Service), as well as available sources and freely accessible data, indicate that due to the unpredictability (geotechnical and hydrological conditions) of the surface stabilization process, Construction on degraded areas is possible (and economically viable without major stabilization measures) only decades after mining has ended. At the same time, it is important to plan the area in accordance with the possibilities (and limitations) of current land uses. (Table 24).
For the study area, we assessed the potential future land use of DOPE areas for the following four periods:
1. These areas are now land that has been stabilized, fully rehabilitated, and features new amenities and facilities (e.g., Park Vista);
In Area 2, maintenance work is being carried out simultaneously with the excavation; the remediation work is scheduled to be completed in 10 years (2035), at which point the surface will have stabilized and will be safe for new (construction) projects in the area;
In Area 3, a permanent stabilization of the surface is expected in certain areas (according to PV monitoring) in 20 years (2045);
Area 4: The final restoration of landscape resources—and thus the safety of major new construction projects—is expected to be completed in 30 years (after 2055).
The categorization, with descriptions of zones 1–4 for future land use, is shown graphically in Figure 76 and in Table 21.