2010-08-18_ENFORCEMENT - C1981008

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excavated by WFC at the previous sampling locations were inspected by Walsh. Each pit was inspected by sweeping off a face of the pit, measuring the depth of the pit and marking the 24-inch and 48-inch depths below the base of topsoil, visually estimating the percent boulders, stones, and cobbles using USDA criteria in the 0-24 inch (A) and 24-48 inch (B) depth zones, obtaining full-thickness soil samples from both depth intervals, placing each into a graduated sieve with a 2-millimeter final sieve size, and sieving the soil into a bottom pan. The volume percent of soil being caught in the 2-mm and larger sieves was estimated, the sieve pans and excavation were photographed, and two samples of the less than 2 mm fraction were obtained from each depth interval for laboratory analysis. No boulders (>25 inches) were observed in any soil pit. All field data were recorded on field data sheets, copies of which are attached to this letter. Samples were analyzed for selenium by Key Laboratories of Grand Junction, Colorado, and other analytes by Servi-Tech Labs of Hastings, Nebraska, with the results recorded in Table 2. The total percent rock fragments criterion was exceeded at NHSS-240A and NHSS-241 A and B, and the average percent rock fragment criterion was exceeded. No other exceedances were noted. NOV Step 3 - This step involved resampling Bench 1 suitable subsoil from the Morgan property at sample points SS-31 through SS-44. The 0-36 inch soil intervals at these points had previously been inspected by Lambert and Associates, Inc. in May, 2010; however, they did not deten-nine coarse rock fragment percentages, nor did they report soil texture using USDA criteria. Walsh calculated gravel percentage from Lambert's grain size distribution curves and recorded these results in Table 3, and calculated soil texture based on Lambert's grain size distribution curves using USDA grain size criteria and texture criteria and recorded these results in Table 4. In addition, pits excavated by WFC at the previous sampling locations were inspected by Walsh. Each pit was inspected by sweeping off a face of the pit, measuring the depth of the pit and marking the 36- inch depth below the base of topsoil, visually estimating the percent boulders, stones, and cobbles using USDA criteria, and obtaining a full-thickness soil sample from the 0-36-inch depth interval. In pits where observed gravel estimates appeared to vary from the Lambert report (SS-32 and SS-34), soil from the 0-36 inch interval was placed into a graduated sieve with a 2-millimeter final sieve size, and sieved into a bottom pan. The volume percent of soil being caught in the 2-mm and larger sieves was estimated, the sieve pans and excavation were photographed, and the results recorded in the field data sheet. Lambert recorded sample SS-32 to have 32% gravel; soil in this excavation was sieved and found to have 10% gravel, suggesting that the excavations were not in identical locations, although they were within about 10 or 15 feet of each other. All other sample points had gravel concentrations similar to those reported by Lambert. No boulders (>25 inches) were observed in any soil pit. All field data were recorded on field data sheets. No exceedances of relevant criteria were measured at any sampling location. Discussion - Soil sampling was conducted at locations specified by WFC. Coarse fragment percentages exceeded relevant criteria at sampling points NHSS-240 and NHSS-241, and the average of the eight coarse fragment percentage samples for Bench 1 Subsoil Substitute Topsoil exceeded the suitability criterion. No other results exceeded relevant criteria. All results are summarized in the attached tables. Chain-of-custody forms and laboratory analytical data are attached to this letter. - s Environmental Scientists and Engineers, LLC