## 4 Discussion and Conclusions  
Mining, as with other industries, needs to face the challenges of lowering its negative impact on the environment. Post-mining excavations, which are the leftovers after extracting mineral resources, are one of the most important ones. They require actions aimed at their reuse, and they cannot just be left and forgotten. This new usage includes a wide variety of options, which depend on the mining and geological as well as economic conditions [5, 7, 11, 16, 29, 30, 31, 32, 33, 34, 35].  
In the case wherein the groundwater table level is above the floor of the post-mining excavation, the potential for reuse becomes limited. The only justified solution in such a situation is to perform the reclamation process in the aquatic direction or for fish production. Using such areas for other purposes (e.g., as forest lands) is technically possible, of course, but the necessary tasks (raising the floor of the excavation) would entail significant financial expenditures. Solutions of this kind are uneconomic.  
In their publications, [PERSON] and [PERSON] [12, 14, 15] proposed slope inclinations for excavations reclaimed in the aquatic direction. Although the results of that research are correct, the authors suggest that the reclamation scope of works and costs  
Figure 14: Calculation results for the slope inclination of 1:1—(a) Coulomb–Mohr potential, (b) shear stresses.  
Figure 13: Shear stresses for the underwater slope inclination of 1:15—(a) clay-type subsoil, (b) sand-type subsoil.  
might be lower if different slope inclinations are used. The analyses of stability and load-bearing capacity of the excavation slopes confirm the justification of such actions. The optimal inclinations for the above-waterline and below-waterline slopes which serve a beach function are now proposed at 1:5 and 1:15, respectively (Figure 15). This solution will allow a twofold or even fourfold smaller scope of the reclamation works related to moving earth masses in order to shape the slopes (depending on the chosen inclination of 1:30-1:60). Despite their increased inclination, the slopes functioning as beaches will still prove stable and safe while also comfortable to use. In the case of water reservoirs which are formed in old excavations of clastic rocks and clays and which are not intended to function as beaches, the optimal inclination for both underwater and above-water slopes is 1:2.  
Importantly, the analyses presented here are hypothetical; therefore, the potential for reducing the slope inclination should be analyzed individually for each case, allowing for the actual geological and mining parameters. The economic aspect, which significantly influences the cost of slope shaping works, should also be considered.  
Therefore, taking into account the research conducted and its results, further research directions can be proposed, which should be: the parametric studies with different soil parameters and the analysis of reclamation costs related to the proposed optimization of reclamation works and the determination of limit slopes related to safe use of the slopes of water reservoirs after the exploitation of mineral resources.  
Conceptualization, U.K.; methodology, U.K. and M.B.-U.; software, M.B.-U.; validation, U.K., for-mal analysis, U.K. and P.S.; investigation, U.K., P.S. and M.B.-U.; resources, U.K. and M.B.-U.; data curation, U.K. and M.B.-U.; writing--U.K., M.B.-U. and P.S.; review and editing, U.K., M.B.-U. and P.S.; visualization, M.B.-U. and P.S.; supervision, U.K.; project administration, P.S.; funding acquisition, U.K. and P.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Polish Ministry of Education and Science Subsidy 2022.  
Not applicable.  
The authors declare no conflict of interest.