Case Study: Comparison of Net Operational Costs and NPV of Project Investment Between HCSD and LCSD

摘要

Park Elektrik Turkey, a Turkish copper producer, had a requirement for an alternative solution for their tailings storage facility that was approaching its maximum capacity. A further increase of the dam height and associated capacity of the existing tailings facility was not feasible. At that time the plant was operating a lean concentration slurry disposal (LCSD) system.It was decided to construct a new tailings storage facility, but instead of selecting a LCSD system a high concentrated slurry disposal (HCSD) system was selected, also referred to as thickened tailings disposal. With this design, a sloped and stable disposal area is formed as the majority of liquid evaporates from the slurry. In addition, the amount of liquid required for transportation is reduced, power consumption per dry ton of deposited tailings is decreased and environmental risks are minimized. This case study, conducted in cooperation with Park Elektrik, compares the two alternative tailings disposal systems, HCSD and LCSD, with a focus on financial impacts. Included in the financial comparison is the complete tailings disposal system, including thickener, pumping system and disposal area. Although the concept of HCSD requires a higher investment for slurry preparation and pumping equipment when compared to LCSD, the net cost per dry ton of deposited tailings proves to be substantially lower. The financial analysis demonstrates a payback time of 1.9 years justifying the initial higher investment for a project with a 15 year life. Factors such as mine closure, rehabilitation and long-term liability have not been included in the financial analysis as presented, but it is believed that including these would create an even stronger case for the HCSD approach.