Applying multi-criteria decision-making processes to deep-level mine ventilation projects

Abstract

Deep-level underground mining costs in South Africa are continuously rising due to the increased depth at which gold is being mined, increasing the need for improved cooling requirements. Therefore, mines must evaluate the various ventilation and cooling optimisation projects required to be implemented throughout their "life of mine" (LOM). The ventilation system of a deep-level underground mine is complex and challenging to evaluate holistically. This study's solution presents ventilation simulations to determine the impact of the projects on the underground environment. The evaluation of an environmental improvement project to decrease the safety risk, while improving underground conditions and best suit the current economic climate, is an essential aspect of the solution developed in this study. This study develops a method to evaluate and rank underground environmental improvement projects to improve thermal comfort in underground mines. The solution utilises a 'multi-criteria decision-making' (MCDM) process, incorporating the 'analytic hierarchy process' (AHP) and the 'technique for order performance by similarity to ideal solution' (TOPSIS) into the method to provide for scientific decision-making. These projects are evaluated based on five criteria: project risk (risk mitigation), the impact on the underground mine environment (such as thermal comfort), cost, energy efficiency, and implementation time. Title: Applying multi-criteria decision-making processes to deep-level mine ventilation projects | Abstract iv The method was implemented on a mechanised deep-level underground mine where the ventilation system was not adapted over time to consider the mine's dynamical development. The method showed that surface refrigeration is the most suitable project solution, and it was implemented at the case study mine to validate the developed solution. The study proves that the MCDM method is an adequate solution to incorporate subjective criteria into the decision-making process, resulting in a scientific and structured approach to making significant and complex decisions. This study led to a publication titled "Prioritisation of environmental improvement projects in deeplevel mine ventilation system" in the journal Mining, Metallurgy & Exploration.