THE APPLICATION OF FUZZY MADM MODELING TO DEFINE OPTIMUM POST MINING LAND USE FOR PIT AREA TO RECOGNIZE RECLAMATION COSTS IN OPEN PIT MINING

Open Pit Mining has considerable damaging effects on the environment of the mining region. These harmful influences have to be controlled during mining operation until mine closure. Different sections of mined land, such as; pit(s), waste dump(s), tailing pond(s), roads, areas for on site facilities and free land zones which are not mined, have to be reclaimed through treatment of environmental pollution and implementation of a permanent Post Mining Land Use (PMLU) after mine closure. Selecting a permanent PMLU for each section of the mined land has a direct effect on reclamation costs and accordingly on final Net Present Value (NPV) of an open pit mining project. Therefore defining of Optimum PMLU (OPM-LU) for each section of mined land in such project is a significant part of the planning phase. Different alternatives of PMLU can be judged based on the relevant criteria and attributes to define the priorities amongst them for each section of mined land. The approach which is presented in this paper uses Fuzzy Multi Attribute Decision Making (MADM) modeling to provide OPMLU for pit area. As the nature of the effective parameters for defining OPMLU is the same as the Fuzzy numbers and includes incremental changes without definite limits, thus the use of Fuzzy MADM modeling can noticeably produce more reliable result than the other techniques. The procedure was implemented also as a case study on a hypothetical copper mine in Northwest of Iran. Lumber Production was defined as the OPMLU for the pit area in the case study. It is finally concluded that through the use of the developed procedure, the PMLU with the highest priority is chosen as OPMLU for pit area. Reclamation costs can thus be estimated in the planning phase of an open pit mining project.