CCR Surface Impoundment Closure

EPA regulations for managing coal combustion residuals (CCR) compelled our client, a large Colorado utility provider, to remove all infrastructure and waste from their decommissioned coal-fired power plant as part of this heavy civil construction project. With plans to market the 50-acre property for future development, the client turned to us for the excavation and closure of six coal ash surface impoundments.

We conducted comprehensive site assessments and engaged with stakeholders to ensure we addressed all environmental and community concerns. By working closely with local subcontractors and within environmental regulations, we developed a detailed project plan that met regulatory requirements and minimized disruption to the surrounding area.

As part of this effort, our team performed the excavation and off-site disposal of more than 421,000 tons of coal and fly ash from the site. This hazardous material removal operation took place in a logistically challenging area adjacent to the South Platte River. We coordinated more than 19,000 loads of material for disposal in a nearby Subtitle-D landfill through a transportation subcontractor, ensuring safe and compliant handling.

Close coordination and logistical planning with the transportation subcontractor was a key element of the project’s success, including decoupling excavation from stockpiling and load-out operations to ensure there were no disruptions to the continuous shipment of outbound waste material, and focused pre-staging and routing of transport vehicles daily.

Water management during excavation was also critical and required constant vigilance to make sure no contaminants migrated to the South Platte River, lending an extra layer of complexity as our team managed the water control structures, dewatering, and hazardous material cleanup from the site.

After removing all waste, our team graded the site and constructed 1,200 linear feet of surface water controls and 360,000 square feet of infiltration ponds. In total, the final site regrading required the cut and fill placement of more than 580,000 cubic yards of backfill material – enough to fill more than 175 Olympic swimming pools.

While overseeing the closure of this impoundment system, our team provided a sustainable solution that aligned with the client’s objectives and met their redevelopment goals. Throughout the process, our team effectively coordinated with subcontractors, oversaw safe handling of hazardous materials, and operated in close proximity to a significant water body, all within the scope of a highly visible project.

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