Chat Mine Reclamation & Repository Construction/Cap

Site Overview

Envirocon was awarded five Superfund Site mine reclamation projects located in the Tri-State Mining District which encompasses approximately 2,500 square miles in three states. Chat mining and smelting activities occurred from 1830 to the 1970s. In 1990, the site was added to the National Priorities List (NPL) under the oversight of the EPA and state Department of Natural Resources.

Project Highlights

• Excavated, transported, and placed 430,000 cubic yards of lead mine waste into a constructed on-site repository
• Constructed and capped the 20-acre clay-lined repository for disposal of mine waste
• Developed a borrow area and excavated, transported, and placed 275,000 cubic yards of clean backfill into excavation areas
• Provided extensive surface and groundwater management services throughout the project
• Removed lead-impacted sediment from a stream bed and restored stream bed and site with native vegetation
• Self-performed 97% of the project without a single safety incident

Value Delivered

Envirocon encountered large volumes of adits/pockets filled with water and endured several weather events during the project. Surrounding soils consisting of predominantly clays became very slippery, and loads became very heavy when saturated. Our project team responded quickly and installed pumps to dewater the affected areas, reduced the size of haul truck loads for added stability, and lowered the speed limit and instituted additional traffic controls around the site which allowed for safer trucking operations and zero incidents.