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Kale Pickford, Environmental Specialist, Division of Minerals and Geology <br />November 13, 2002 <br />Page Two <br />AGGREGATE <br />INDUSTRIES <br />in soil was bracketed by abatement excavation confirmation samples, test pit samples or soil <br />boring samples. <br />• The BTEX and Polynuclear Aromatic Hydrocarbon (PAH) concentrations observed in soil <br />samples collected from the site did not exceed the Tier 1 Risk-Based Screening Levels (Tier ] <br />RBSLs) established by the OPS. The Tier 1 RBSLs are applicable to assessment and <br />remediation, <br />• Even though additional soil abatement is not warranted when comparing the on-site soil <br />sample results to the Tier 1 RBSLs, Aggregate Industries will excavate additional TEPH <br />impacted soil, if present, prior to cessation of the dewatering activities. When those future <br />excavation activities are performed, a TEPH concentration of 500 mg/Kg will be used as a <br />guide for completing the additional soil abatement activities. <br />Aggregate Industries originally anticipated that additional extraction activity would be occurring adjacent <br />to the abatement area and that any remaining contaminated soil would be excavated. It has been <br />determined, however, that aggregate reserves in this area are not economically recoverable and will not be <br />mined for processing. <br />Paragon's response indicated that additional soil abatement was not warranted at the time that the <br />technical revision was submitted. Additionally, the ground water samples obtained throughout the <br />monitoring period and the fact that there has been no evidence of contamination in the dewatering trench <br />further verifies that soil contamination has not impacted groundwater. We believe, therefore, that DMG's <br />goals have been achieved without excavating any remaining contaminated soil and that no further action <br />is necessary in this matter. While your letter of October 24 provides for discontinuance of groundwater <br />monitoring, we would appreciate your written concurrence with the consultant's opinion, as set forth in <br />his September 20, 2002 letter, that no additional assessment or abatement activity is warranted and that <br />site closure should be granted by DMG for the 2001 diesel-fuel release. <br />Mining activity at the 83'~ Joint Venture Pit will be completed within the next thirty to sixty days. <br />Although dewatering activity will continue throughout the reclamation phase, extraction and processing <br />equipment will be removed from this site in the near future. We would therefore respectfully request your <br />earliest consideration and response in this matter. Please contact me at (970) 336-6526 if you have any <br />questions or need additional information. <br />Very truly yours, <br />C <br />Connie Nickle Davis <br />Support Services Representative <br />cc: Scott Rutherford, Paragon Consulting Group, Inc. <br />Aggregate Industries-WCR, Inc. - <br />Mike Refer, Jamie Gaboriau, Pat Ward, Tom Maul, Mike McAfee <br />Connie Nickle Davis, Support Services <br />P. O. Box 337231, Greeley, CO 80633 <br />970-336-6526 Fax: 970-378-6856 <br />