Mine closure risk management: An integration of 3D risk model and MCDM techniques

Mine life is limited to mineable reserve, but economic, social and environmental factors can make mine life shorter than what is expected. Mine closure is associated with adverse on-site and off-site impacts such as unemployment, the loss of community services and pollution which threaten achieving the sustainable development goals. Therefore, mine closure risk management is necessary for reducing the negative effects. The present study aimed to develop a generic procedure for mine closure risk management. To this end, a three dimensional (3D) risk model was developed for assessing mine closure risks. The 3D risk model can fix the deficiency of 2D risk model by considering the time value of risk. Mine reclamation is a risk treatment option which requires the selection of optimal Post-Mining Land Use (PMLU). The optimal PMLU depends on the risks identified by the 3D risk model. In addition, a hybrid approach involving three Multi-Criteria Decision Making (MCDM) methods was developed for optimal PMLU selection. Twenty six different criteria including six economic, four technical, three landscape and environmental, seven social and six mine site factors were proposed. Finally, the proposed risk management approach was implemented in Choghart iron ore mine of Iran. The results indicated that the identified events had a 51.4% low, 22.9% medium, 143% high and 11.4% extreme risk levels and accordingly revegetation with native species was recommended as the optimal PMLU. Compared with the 2D risk model, the assessment results are more effective and practical by adding the time value of risk which can help budget planning for risk treatment. (C) 2018 Elsevier Ltd. All rights reserved.