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Visitors to the Rocky Flats National Wildlife Refuge may notice some heavy equipment activity on the southwest side of the Central Operable Unit — also referred to as the U.S. Department of Energy (DOE) Office of Legacy Management (LM) Rocky Flats Site, Colorado — located in the center of the refuge.

DOE is repairing two sections of the hillside where an old, closed landfill, called the Original Landfill, is located. Soil on this steep hillside has been slipping downhill for several years and previous repairs did not provide a long-term fix. The project involves installing steel anchors that will hold the soil deep into bedrock and subsurface drains that will route shallow groundwater away from the slipping areas. Work began August 7 and is expected to finish in May 2020. Crews are scheduled to work 7 a.m. to 5 p.m., Monday through Friday (except during holidays), until the project is finished.

While DOE does not expect to encounter hazardous or radioactive materials, debris exposed during drilling and excavating will be screened for proper disposal. Soil moved during repairs will be put back in place when possible and any excess material will stay on-site to fill other areas.

The Original Landfill was used as a construction and municipal waste dump since the Rocky Flats Plant began operation in 1952 and was used through 1968. During those early years, trash was dumped over the steep hillside, then covered with dirt. Although the landfill was never intended to be used as a hazardous or radioactive waste disposal site, some hazardous materials like paints, solvents, asphalt, and other chemicals were most likely disposed in the landfill. On one occasion, some depleted uranium being transported on a pickup truck caught fire and was placed in the landfill to burn out. Shortly after, what remained was removed.

In 2005, new soil cover and drainage features were installed as part of the Rocky Flats Closure Project. Surveys targeted the remaining spots of low-level radioactive material, which were removed before DOE graded and covered the landfill. Years of data from landfill soil and water monitoring before, during, and after cleanup show very low levels of hazardous or radioactive materials in the landfill.

More than 260 steel anchors will be drilled into each section to stabilize the east and west sides of this hillside. Each anchor will be capped with an 8-foot concrete square that will be buried to make the hillside look more natural. Drains will be installed underground to move groundwater away from the areas being anchored.

The Colorado Department of Public Health and Environment approved the contact record, which describes the project and the soil disturbance review plan associated with excavation. This contact record was emailed to engaged stakeholders and posted on the LM Rocky Flats website.

Go to to view the Rocky Flats Site documents.

Go to to view contact records, including more project details in document RFLMA CR-2019-02.

For more information, contact Rocky Flats Public Affairs at or (720) 880-4350.