## 3 Methodology  
As was mentioned, the methodology of multicriteria analysis applied in our study relies on the Analytical Hierarchy Process (AHP) [7]. Our approach consists of two stages (Figure 2). In the first one (stage A), which has been described in [6], we identified, the above-mentioned mining waste criteria (K1-K7) based on their economic and environmental characteristics (A1) and employed the AHP methodology to calculate weights of these criteria (A2). Then, we allocated points to each of the 20 mining waste sites for each of the proposed criteria from a 3-point scale, where 1 point indicated the least suitable to be used for industrial purposes and 3 was the most likely to be used for industrial purposes (A3). In the last (A4) part of this stage, we calculated the weighted score for each mining waste sites. This provided the final ranking of mining waste that should be considered for potential new use (Table 1). In the second stage (B), which is the main subject of this paper, firstly we identified the main potential mining waste uses (B1). Next, we constructed a three-level AHP decision hierarchy structure, which was used to determine weights of potential mining waste uses (B2), weights of alternatives (mining waste sites determined in stage A) with respect to each of the potential mining waste uses (B3), and the final score of each site (B4). As previously [1], we determined the weights based on seven responses that were provided by the authors and four additional experts from specializations such as spatial planning, environmental protection, resource management, and mining administration. The experts represent regional institutions such as the Institute for Territorial Development (Marshal Office), the District Mining Office, the Regional Inspectorate of Environmental Protection, and Wroclaw University of Science and Technology. For the calculations, we employed the AHP template proposed by [PERSON] [35]. Figure 2: _Cont._In detail, Part B of our study, according to the AHP theory [7; 36], consists of the following steps:  
1. developing the model,
2. deriving weights for the criteria,
3. checking the consistency,
4. deriving local preferences for the alternatives,
5. deriving overall priorities and making the final judgement. Step a) involves constructing a hierarchy to analyse the decision. The AHP decision model for selecting waste for reuse is structured into a hierarchy of goal, criteria, and alternatives (Figure 3). In the case where the goal is to select the deposited mining waste for new use, the criteria are potential uses of mining waste, and the alternatives are the individual mining waste sites. Step b) consists of deriving weights of the criteria, and the importance of criteria is compared pairwise with respect to the desired goal to derive their weights. Next, in step c), check of the consistency of judgments is performed; it involves a review of the judgments in order to ensure a reasonable level of consistency in terms of proportionality and transitivity. Step d) consists of deriving the local preferences for the alternatives. Priorities for alternatives are derived separately for each criterion following the same method as in step b). Consistency check is also carried out. In step e), overall priorities of the alternatives are calculated, i.e., the obtained alternative preferences are combined as a weighted sum to take into account the weight of each criterion. The alternative with the highest overall priority constitutes the best choice. Figure 2: General scheme of the methodology for multicriteria analysis of mining waste potential of new use for the selected sites.