California Gulch- OU 11 Superfund Site

California Gulch OU11Leadville, Colorado:

PWT used value engineering and sustainable design to remediate toxic metal-contaminated soils in former mining sites near Leadville, Colorado. In operable unit 11 of the site, PWT managed an innovative environmental remediation project to treat and re-vegetate 150 acres of irrigated meadows pastureland and 18 acres of fluvial deposits that bordered approximately 3,000 feet of the Arkansas River.

The design incorporated a unique remediation process. It included the application of a lime-based amendment that is a by-product of sugar beet processing: the first large-scale application of this type of in-situ soil treatment. In order for this amendment to work, it was important to thoroughly incorporate the lime mixture into the contaminated soil. A state-of-the-art soil mixer was incorporated into the design, making the process more efficient. The time and cost savings for this value-engineered process allowed an expansion of two acres of treatment and covered the subsequent year’s costs. It also saved the energy and environmental pollution impacts of the traditional method of extensive soil removal.

This unique process is helping to create healthy soils that support the germination of new vegetation. Based on this data, the EPA is considering using the same method to treat the Clark Fork River NPL Site, a much larger site in Montana.

See an EPA report about California Gulch at

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