The San Rafael Mine, which is operated by Minsur S.A. (Minsur), is an underground mine located 120 km from the city of Puno in southeast Peru, in the eastern cordillera of the Andes at 4,500 masl. It is the third largest tin producer in the world.
The B3 tailings storage facility (TSF) is operational with 15 Mt of capacity. The main structure is the 90 m high rockfill dam (with a 450 m crest length) that was raised following the central axis method. In addition, B3 TSF has another containment structure to the north called Dike 2.5, which is in contact with the water pond of B3 TSF.
One of the main challenges of the project is adequately integrating strategic aspects of tailings management with the operational activities of the mine. Knight Piésold is promoting industry best practices and global initiatives, such as those proposed by the International Council on Mining and Metals and the Mining Association of Canada, to successfully drive a sustainable and long-term project.
Knight Piésold was appointed by Minsur as the civil-geotechnical designer for the project in 2010. Since then, Knight Piésold has provided the following services: geotechnical, geological, and geochemical characterization, including liquefaction and seismic behavior analysis; water balance; hydrological and hydraulic analysis; civil engineering design; stability analysis, risk management support, and potential failure modes evaluation; and other services. In addition, Knight Piésold has provided technical assistance and continuous quality control during construction of B3 TSF and Dike 2.5, verifying compliance with the design intent.
Moreover, Knight Piésold was designated as the Engineer of Record for the project in 2018 and has since been providing technical assistance for all stages of its life cycle and participating in monitoring, performance assessment, and risk management.
The final raise of the B3 TSF (4,490 masl) was completed, and the maximum capacity for the disposal of tailings in the TSF has been reached.