Gypstack Complex Closures

Site Overview

Envirocon executed the closure of two phosphogypsum stacks (gypstacks) at a former fertilizer production facility. The scope of work included mass earthwork, placement of substantial quantities of liner, and installation of various trenching, piping, and conveyance systems.

Project Highlights

• Dewatered, excavated, placed, and graded over 1.5 million cubic yards of saturated and dry phosphogypsum
• Placed over 6.9 million square feet of liner including HDPE and FML to line ponds and trenches and cap graded phosphogypsum
• Installed 52,500 linear feet of trenching, underdrain, and piping for the conveyance of both clean and impacted stormwater
• Hydroseeded the entire site complex and provided ongoing operations and maintenance services as needed
• Completed over 296,000 manhours with zero safety or environmental incidents on the projects

Value Delivered

Envirocon worked with the client to review and field fit (design/build) the original grading and cap design of the gypstack cover system because the gypstack elevation was lowering and excavation quantities changed significantly as the stack dewatered.