Crews are making great progress at the Maxey Flats Disposal Site. All 274 trench sumps are undergoing preparation for the final cap. Check out these agency photos of recent work within restricted area.
Protruding Trench Sump Risers
Of the 274 trench sumps on site, 83 are active, protrude through the liner and extend down to the waste trenches. These sump risers must be cut off below surface. But before this happens, bentonite must be placed in sumps to absorb any standing liquid in the bottom of the sumps.
Grouting Trench Sumps
The sump must then be filled with grout. This is a glimpse into the top of a trench sump riser that has just been filled with grout. This is part of properly sealing the sumps, which represent pathways that lead from the surface to the buried waste in trenches.
Existing Liner Repair and Placement of HDPE Flat Stock
Repair is made to the existing liner where possible and a 1.5-inch-thick piece of high-density polyethylene (HDPE) flat stock is placed over the sump with steel spikes. Finishing the top surface of the sumps in this manner is a critical design feature. It is to ensure that the top surfaces of abandoned sumps are completed in such a manner that settlement does not allow the sump risers to penetrate the final closure cap.
“Trench sump risers are expected to be leveled at a rate of 15 per day once that part of the operation is in full swing,” said Shawn Cecil, project coordinator for the Department for Environmental Protection. “There are also previously abandoned sumps that need additional preparation. Completion of these efforts is expected by the end of June.”
This work is funded utilizing the trust fund established for the final closure of the facility and includes abandonment of several structures, including 83 existing active sumps, and improvements to previously abandoned sumps for long-term stability beneath the final cap.
The Maxey Flats Disposal Site is a low-level radioactive waste landfill located in Fleming County, approximately nine miles northwest of the city of Morehead. The facility was privately operated from 1963 to 1977, receiving approximately 4.7 million cubic feet of waste containing low levels of radiation.
To ensure proper closure and care, the Commonwealth of Kentucky assumed ownership in 1978 and is obligated by a 1995 Consent Decree to carry out the remaining remediation and monitoring efforts.
The site was added to the National Priorities List (NPL) in 1986. The NPL is the U.S. Environmental Protection Agency’s list of national priority sites among the known or threatened releases of hazardous substances, pollutants, or contaminants throughout the United States.
The remedy selected for the Maxey Flats Disposal Site has included several phases and the site has been under an interim cap for about the last 12 years to allow for natural settling of the material in the landfill. The placement of the final cap is expected to be the last substantial remedial construction effort, after which the site will be subject to ongoing monitoring and maintenance by the Commonwealth.
Efforts to complete the design for the final cap are nearly finished.
“The design of the final cap is now at 90 percent, so we have details including estimated costs and an estimated timeline. We will be bidding the work through the Finance Cabinet shortly,” said Cecil.
The Construction of the final cap is scheduled to begin later in 2014.
More information on the Maxey Flats Disposal Site can be found here on the Kentucky Division of Waste Management’s website. You may also contact Shawn Cecil at Shawn.Cecil@ky.gov or 502-564-6716, ext. 4754.
Click here to view all previous Naturally Connected posts on the Maxey Flats Disposal Site.