How to assess landscape changes caused by land subsidence due to deep coal mining? Methodology tested in the mining area of Jastrzębie coal company (Southern Poland)

Land subsidence is among the most significant impacts of coal mining, posing a particularly prevalent challenge in Upper Silesia, Poland, where its adverse effects are well-recognized. Under Polish law, companies intending to mine coal must provide documentation as part of the concession application process. This includes a decision on environmental conditions - Environmental Impact Assessment (EIA). A critical component of the EIA is the Landscape Impact Assessment (LIA), which examines changes to the landscape, including potential visual and physical impacts. This article presents a methodology for assessing landscape changes resulting from post-mining subsidence, developed for the EIA report required to secure a mining concession for Jastrzębska Coal Company. The methodology includes an analysis of the landscape structure (delimitation of landscape units), identifying natural, cultural and visual values, and evaluating future landscape changes due to the subsidence. The changes are assessed for two variants using viewshed range analysis and by determining the scale of landscape changes caused by subsidence within the landscape units. The study involved cartographic analysis, statistical calculations, and visualizations presented as maps. The results suggest that visual values (viewshed range) will increase. A significant impact on the delimited landscape units is anticipated in several areas, including subsidence reaching 11,5 m, which will affect up to 94 % of the area of the landscape units in Variant 1 and 80 % in Variant 2. The innovation of the methodology is using the quantitative methods employed for analyzing view changes to ensure maximum objectivity in the assessment and implementing a numerical scale for describing landscape changes due the land subsidence.