CCR Basin Closure – Roxboro, NC

Project Scope Highlights

• Clean Closure of 14,500,000 cubic yards of CCR Material
• Dredging & Processing 400,000 cubic yards of CCR
• Landfill Construction – 81 acres
• 2 million yards of Soil Placement
• 35 million square feet of Geosynthetic Liner Installation
• Landfill Closure – 210 acres
• 500,000 cubic yards of Cement Soil Mixing to construct 4,600 individual 8-ft diameter columns of DMM Wall
• 0 Acre Leachate Basin
• Up to 72” Pipe Fusion and Installation

The purpose of this project was to meet state regulations to fully excavate and clean close 300 acres of CCR basins over a twelve-year period. The work consisted of mechanical excavation of 14.5 million cubic yards of CCRs within the basins and constructing over 81 acres of landfill.

The client brought Trans Ash on-board during the design phase.  The team approach allowed the final designs to factor in our constructability methods and phasing for project completion. Since pre-project planning is essential to a project of this size, the team approach enabled all the shareholders to spend the necessary time to develop the detailed and safe work plan.

Environmental factors and water management created a unique set of challenges for this project:

• Landfill construction was critical path for the first two years of the project. Tackling groundwater challenges required an average of 20 feet of earthwork throughout the landfill footprint.  To meet an aggressive schedule for completion, the team operated multiple borrow areas and haul roads at the same time in addition to importing clay from offsite sources.
• The schedule required earthwork and geosynthetic liner installation to be constructed during winter months. The team was able to overcome weather limitations to meet stringent moisture and compaction specification requirements for clay and liner placement.
• High CCR Hauling Production: The team is achieving a CCR production of over 2,000,000 cubic yards per year. This high production is possible due to industry leading CCR conditioning techniques and efficient placement operations. Additionally, Trans Ash owned equipment fleet includes high-capacity articulating dump trucks and large size excavators.
• The scale of this excavation demanded the project team to be held to the highest level of safety throughout the project. Trans Ash worked with the customer and engineer to develop an excavation plan that included setbacks and safe work practices.  This plan incorporated both engineering analysis and Trans Ash’s historical experience, resulting in a plan that improved the safety of this project as well as other excavations throughout the customer’s system.
• DMM Retaining Wall – First of its kind application, Trans Ash was selected to complete the design and installation of an 81’ tall DMM gravity retaining wall. Trans Ash subcontracted an experienced engineer and DMM contractor to complete the design build team. This scope consisted of 4,600 individual 8-ft diameter columns and required 500,000 cubic yards of soil mixing using 3 drill rigs. The project was completed on schedule and under budget.