2006-04-05_REVISION - M1978056 - Laserfiche WebLink

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~~ December 6, 20(15 Mr. Bred Janes Varna Companies, Inc. 8120 Gage Street Frederick, Colorado 80516 Re: Soil Remediation Completion Report Varna Companies, Inc. Durham Pit 117 1431 E. 1t" Street Greeley, Colorado DMG Mine ID: M-1978-056 CGRS Project #: 1-135-99Z9ab Dear Mr. Janes: ENVIRONMENTAL • CONSTRUCTION • COMPLIANCE This report documents results of the bioremediation treatment of petroleum contaminated soil that was excavated during the January Z0, 2004, cleanup of the former fueling depot at the referenced Vatra Companies, Ina (Varna), Durham Pit 117. As noted in the Soil Remediation Report and Treatment Plan prepared by CGRS, Inc. (CGRS), dated February 12, 2004, soil excavated from the former fueling depot was stockpiled on a concrete pad south of the truck scales. The estimated loose volume of soil stockpiled was approximately 430 cubic yards. Following the treatment plan guidelines, manure compost was blended into the stockpile at a 25 percent to 30 percent mixture. Since the concrete pad provided an existing barrier to prevent potential cross- contamination with underlying soil without disturbing another area of the property, the soil stockpile rr:mained on We concrete pad in a six- to eight-foot mound throughout the treatment process. The treatment process included fuming and blending the soil on a bi-weekly to monthly basis utilizing on-site excavation equipment and applying water as needed to maintain adequate moisture. Between October 8, 2004, and November 9, 2005, CGRS conducted three soil sampling events at six-month intervals to monitor the treatment progress. Each sampling event was performed by obtaining soil samples approximately 6 feet into the core of the pile with a hand auger at six random locations. The soil sample locations were on the southwest (SP-1), south-central (SP-2), southeast (SP-3), northeast (5P-4), north-central (SP-5), and northwest (SP-6) sides of the stockpile. Soil samples were submitted to Technology Laboratory, Inc., in Fort Collins, Colorado, for analysis to determine concentrations of total petroleum hydrocarbon diesel range organics (1'PH-DRO). Laboratory analysis results are summarized in Table 1. Copies of the laboratory analysis reports and chain-of-custody documentation are included in Attachment A. Review of Table 1 illustrates downward trends in TPH-DRO concentrations over the treatment period. Results of the November 9, 2005, soil sampling event show hydrocarbon concentrations were below the 500 mg/Kg target cleanup level. P.O. BOX 1489 FORT COLLINS, COLORADO 80522 PHONE: 970-493-7780 FAX: 970-493-7986