Application of Z-numbers theory to study the influencing criteria in underground mining method selection

The purpose of this study was to prioritize and determine the importance of effective factors in selecting the appropriate underground mining method (UMM). This study also evaluates the uncertainty and various life-threatening/mortal and financial risks associated with these criteria. In the present study, 43 influencing criteria for underground mining method selection (UMMS) were identified and classified into two main groups. Then, a model was proposed by employing the Z-numbers theory (Z-NT). A total of 25 specialists from around the world were approved for the study, and 10 of them returned questionnaires. By applying Z-numbers and using the proposed model, the uncertainty of the experts' opinions was highly reduced. Finally, the model was applied to the Angouran Lead and Zinc (L&Z) Mine in the northwest of Iran for verification. The findings indicate that within every group of criteria, the weighting of factors determined in this study is in good harmony with the key factors considered in the selection of mining method at Angouran Mine. Also, based on the technical reports of Angouran Mine, the mine is facing various risks. Therefore, this research has also been examined from a risk assessment perspective, and the findings of the proposed model have been put against the factors influencing the various risks in the Angouran Mine. The results show that the factors that have the highest weight in risk proneness are stope collapse, underground water inflow into the stope, and machines’ downtime.