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1.0 EXECUTIVE SUMMARY <br />Greystone Environmental Consultants, Inc. (Greystone) has preformed a soil loss analysis on the seven <br />Thermal Event Small Area Exemptions (SAES) located at the West Elk Mine (Permit # C-80-007) per the <br />request of the Colorado Division of Minerals and Geology (CDMG). The purpose of this analysis is to <br />demonstrate sediment generated from a 10-year, 24-hour storm event from the Thermal Event SAES is <br />equal to or less than sediment generated from the adjacent undisturbed slopes. This evaluation has <br />demonstrated that erosion control structures protecting the reclaimed areas can be safely removed. <br />1.1 METHOD OF ANALYSIS <br />This review and analysis is made using the Revised Universal Soil Loss Equation (RUBLE), developed <br />by United States Department of Agriculture (USDA), Agricultural Research Service. The RUBLE <br />method for determining soil loss is the recommended method of the U.S. Department of Interior, Office <br />of Surface Mining. This analysis is based on field information provided by Henry Barbe, Environmental <br />Coordinator, Mountain Coal Company; field data collected by Charles Florian, Staff Ecologist, <br />Greystone; and other sources as referenced herein. <br />1.2 PROJECT DESCRIPTION <br />The project consists of seven reclaimed SAES located in the Thermal Event area of West Elk Mine: <br />TEA I W Thermal Event Area -Main Pad (West) <br />TEAK Thermal Event Area-Main Pad (Central) <br />TEA 1 E Thermal Event Area -Main Pad (East) <br />TEA2 Thermal Event Area 2 <br />TEAG Thermal Event Area G <br />TEA3 Thermo] Event Area 3 <br />TEA4 Thermal Event Area 4 <br />Erosion control structures such as silt fence, circumvential ditches and hay bales have protected the SAES <br />to allow for sustainable vegetation establishment. Per the field investigation conducted November 5, <br />2004, and subsequent report, vegetative cover at all seven sites was estimated to range from 15 to 25 <br />percent with no erosion problems observed. <br />1.3 CRITERIA <br />The removal of the erosion control structures is dependant on the demonstration that sediment generated <br />by the Thermal Event SAES are equal to or less than sediment generated by adjacent undisturbed areas <br />during a 10-year, 24-hour storm event. <br />Thermal Event RUBLE Report.doc 1-I <br />