Tetra Tech is the engineer-of-record supporting tailings storage facilities in Peru for Nystar, the world’s largest zinc producer. Tetra Tech’s services include detailed geotechnical, hydrological, and environmental engineering, as well as implementation of an ISO 14001-based environmental management system. For one of the company’s new tailings storage facilities, Tetra Tech prepared designs for the dry stack facilities, tailings loading and offloading stations, and surface water management. Tetra Tech also prepared mine and operation-wide closure plans involving hydrogeology studies, GIS-based databases, soil and groundwater quality assessments, slope stability analyses, river restoration and vegetation regeneration.