Decision-making methodology for a groundwater drainage system using the simplified Analytical Hierarchical Process (AHP) in surface mining

The objective of this research is to propose the use of a methodology in long-term operational planning, so that it can be applied in the selection of a short-term drainage system through the Hierarchical Analytical Process (AHP). Currently, model information crosses are used to determine the volume or flow that will enter the pit. This methodology focuses on the selection of technical, economic and safety and environmental parameters so that the result is viable for all the dimensions that a mine encompasses. The research was carried out with the help of an expert in drainage systems and hydrogeology from a mine in the north of the country, who in turn was part of the research, since subjective evaluations are used for the development of matrices that will give priorities to the criteria and sub criteria proposed and accepted by it. These matrices will be related between each parameter, sub parameter and alternative, so that the priority vectors can be found. Some thirteen matrices were built based on the Saaty scale, which serves to transform subjective into objective assessments. It was possible to perform a basic matrix calculation in Excel with the SUMPRODUCT formula and a positive result was obtained, considering the drainage system currently used in the selected mine. An additional sub-criterion was added within the technical criteria so that the result is the most consistent with reality and the rugged geography of our Peru. It was possible to conclude with the application of the Hierarchical Analytical Process that the best drainage system to be used was that of pumping wells within the pit together with pumping stations and precisely the one that the mine currently uses. This indicates that the application of this methodology is reliable, viable and capable of deciding.