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• • <br />AGGREGATE <br />Kate Pickford, Environmental Specialis4 Division of Minerals and Geology INDUSTRIES <br />October 26, 2001 <br />Page 17vee <br />TEPH contamination was observed in the "smear" zone away from the source area in the West Wall <br />North End and South Wall Middle soil samples. <br />The TEPH concentrations observed in the Wesi Wall North End, Bottom # l and South Wall <br />Middle soil samples collected from the abatement excavation exceeded the TPH Threshold <br />established by the Division of Oil and Public Safety (OPS) of the Colorado Department of Labor <br />and Employment. The TPH Threshold is a soil standard applicable to assessment only and is no[ <br />applicable to remediation. The lateral and vertical extent of TEPH contamination in soil was <br />bracketed by abatement excavation confirmation samples, test pit samples or soil 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 I <br />RBSLs) established by the OPS. The Tier I RBSLs are applicable to assessment and <br />remediation. <br />• Even though additional soil abatement is not warranted when comparing the on-site soil sample <br />results to the Tier 1 RBSLs, Aggregate Industries will excavate additional TEPH impacted soil, if <br />present, prior [o cessation of the dewatering activities. When those future excavation activities <br />are performed, a TEPH concentration of 500 mg/Kg will be used as a guide for completing the <br />additional soil abatement activities. <br />A check in the amount of $188.00 is enclosed herewith as the filing fee for this technical revision. Please <br />contact me at (970) 336-6525 if you have any questions. <br />Very truly yours, <br />~~~ ~~ <br />Connie Nickle Davis <br />Support Services Representative <br />Enclosures <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 60633 <br />970-336-6526 Fax: 970.378fi856 <br />