(The Center Square) – Los Alamos National Lab is saving millions with excavated dirt reuse. By processing and reusing soil already excavated on-site and using it for new building foundations, roads and utility and stormwater lines, Los Alamos National Laboratory has saved $11.7 million.
“Cost savings to the Laboratory is only one of the benefits,” Jen Payne, chief operating officer for the Associate Lab Directorate for the Environment, Health, Safety and Quality, said in a press release from the Lab. “The reduction of greenhouse gas emissions is also important and helps us to meet our sustainability goals while also decreasing the number of trucks on our already heavily trafficked roads.”
The program could also make the Lab more green, avoiding 1,850 round trips for trucks on the roads. It will save 19,300 gallons of diesel and eliminate 428,000 pounds of carbon dioxide emissions, the release said.
Los Alamos National Laboratory has over one million square feet of construction planned in the next five years in the Pajarito Corridor. It means the Lab requires thousands of cubic yards of usable dirt, free of debris, known as engineered fill, for foundations, roads, and infrastructure.
Soil near the Lab is typically a poor-quality volcanic tuff. Therefore, soil has traditionally been hauled on-site.
However, the new collaborative initiative is significantly cutting costs.
Processing engineered fill on-site costs about $13 per cubic yard. Previously, the Lab paid a vendor about $247 per cubic yard. On 50,000 cubic yards recently processed, this saved the Lab $11.7 million. Processing 5 million cubic yards could save nearly $1.2 billion according to the math, enough to cover the U.S. Federal deficit for several hours.
For over 10 years, the Lab has hauled dirt from construction project excavations to the Sigma Mesa Clean Fill Stockpile in Technical Area (TA)-60, hoping to get use from it.
“The material met environmental requirements and was verified clear of trash, wood, concrete, other construction debris, and hazardous materials,” the release said. “But this 50,000 cubic yards of dirt still wasn’t the engineered fill that construction projects require, so it wasn’t being used.”
Late last year, the TA-51 warehouse complex project in the Pajarito Corridor started site preparations for four new 20,000-square-foot structures. The structures would require approximately 130,000 cubic yards of engineered fill material.
The TA-51 warehouse project team started the process of screening, testing, and blending the Sigma Mesa Clean Fill Stockpile material with on-site soils to make the desired engineered fill. Additionally, the team won a Patricia E. Gallagher Environmental Award, recognizing its efforts.
Following the warehouse project, Paul Luik, strategic improvement management lead for the Associate Laboratory Directorate for Infrastructure and Capital Projects, reached out to the environmental and logistics teams to inquire about how the resources could get further use.
An engineering team joined the effort to create a plan for testing and ensuring the soil meets engineered fill standards, and Infrastructure and Capital Projects provided it with funding.
In the final two months of the 2023 fiscal year, the Logistics Heavy Equipment Roads and Grounds group processed over 50,000 cubic yards of fill dirt. The crew used its excavators and loaders for 10 hours a day, including on weekends, screening to remove materials one inch and larger, like roots, cement, and asphalt.
After processing the soil, the Engineering Services Materials Testing Laboratory team performed a proctored test, measuring the soil’s compaction and moisture levels.
“With the processing and testing formalized and the initial projects completed efficiently and safely, the Lab is now creating its own engineered fill while dirt continues to be excavated from projects,” the release said.
So what happens to old concrete and asphalt after demolition projects? Aside from reusing dirt at the Lab, recycled concrete and asphalt materials from demolition projects are made available for construction projects, roads, and parking lots.
Two years ago, the Lab sent 850 tons of asphalt and 990 tons of concrete to Los Alamos County Eco Station for disposal. However, last year, the county ran out of storage space on-site. Until July this year, the Lab had to send asphalt and concrete to GM Emulsion, a vendor in Española.
Since this summer, GM Emulsion has had an operational permit to process waste concrete at the Los Alamos Eco Station. That said, the Lab no longer has to transport these materials to Española, cutting trucking costs.
“This mixture of concrete and asphalt is called conphalt and is known industry-wide as recycled base course,” Michael Moss of Environmental Protection and Compliance said in the release. “As the Lab continues to grow, there will be many uses for this material in the coming years.”
