Developing a new social impact assessment model for deep open-pit mines

Various open-pit mines, particularly porphyry copper mines, are anticipated to reach depths of more than 1000 m, and short knowledge of social impacts at such depths is a significant challenge for the mining industry's future. In the present study, 37 social impact factors of deep open-pit mines are recognized as the first step for a Social Impact Assessment procedure. As a 37 × 37 matrix for weighting the importance level of each factor will be complicated and unreliable, these factors are classified into 10 categories and weighted using the Z-Fuzzy Delphi AHP technique. 26 experts worldwide were recognized as qualified for the study, among which 14 questionnaires were returned. The Cronbach coefficient was calculated to check the level of uniformity of the questionnaires, and the value was determined to be 0.925 for I (Importance) and 0.911 for R (reliability), which shows a high level of uniformity in the expert's predictions. By applying Z-numbers, and using fuzzy Delphi mathematics, the uncertainty of the experts' opinions was highly reduced. The results showed that the most critical social impact categories in deep open-pit mines are workplace safety (13.8%), employment (10.9%), and revenue generation (10.7%). Next, the social impact factor's score was determined using the scenarios described in this study. Finally, the methodology was applied to the Sungun Copper Mine (SCM) in the northwest of Iran for verification. The Social Sustainability Score (S_s) for the SCM was determined to be 6.364, which shows a medium level of sustainability. Finally, the proposed methodology can be used to determine the social responsibility level of any metal mining project.