Optimization of tailings disposal method using fuzzy analytic hierarchy process

Due to the increasing demand for metals, the extractable grade of metal deposits has been decreasing and caused an increase in the amount of tailings. Increase in the volume of tailings requires proper attention to tailings disposal, the establishment of tailings dams, water consumption and prevention of environmental and groundwater pollution. Since tailings disposal consists of many stages such as discharge, thickening technology and location, and transportation, selection of the best disposal method is a complicated task. Nowadays, decision-making methods are widely used and they are very reliable and efficient. Therefore, a model based on fuzzy analytic hierarchy process (AHP) has been developed in this study to optimize tailings disposal method selection. In the model, 21 criteria and a wide range of alternatives have been introduced. The model has been applied to the Sangan Iron Ore Project (STOP). The concentrator plant of STOP will produce 75 million tons of tailings during the mine lifetime. Since the current disposal method wastes 1.5 million cubic metres of water annually and the project is located in a dry region, the proposed model has been used to investigate other options and the results show the filtered technique is the best alternative.