The Potential Use of Solid Waste and Mine Water for Land Rehabilitation of the Coal Mine-Affected Area in Slovenia

The rehabilitation of post-mining sites is crucial due to the severe environmental impacts of mining, including land degradation, heavy metal pollution, and loss of biodiversity. Effective reclamation strategies are essential to reverse these impacts and enable sustainable land use. This study presents the possibility of the rehabilitation of a post-mining area in Velenje, Slovenia, using artificial soils made from combustion by-products amended with lignite and organic compost, and explores the potential of lignite mine water for irrigation. This approach introduces an innovative solution that differs from the traditional methods of rehabilitating degraded areas. Physicochemical and phytotoxicity tests were conducted to determine the quality of the soil substitutes. The analysis revealed that the pH, salinity, and chemical composition of soils positively impacted Sinapis alba growth as a test plant, with the most promising compositions containing 20–30% of lignite by weight as a replacement for organic compost. Irrigation water quality parameters, such as electrical conductivity (0.87 dS/m), the sodium absorption ratio (2.09 meq/L), and boron content (0.05 mg/L), indicated a low soil dispersion risk, while the residual sodium carbonate (3.02 meq/L) suggested a medium risk. Although, the concentration of toxic elements did not exceed the threshold limits; the long-term irrigation with mine water requires the monitoring of the molybdenum levels. These results suggest the potential for using artificial soils and mine water in post-mining land reclamation but highlight the need for the monitoring of their quality.