• In addition to soil sampling, a complete soil profile description was completed at each
<br />backhoe pit location. Soils description followed standard Natural Resources
<br />Conservation Service (NAGS) field methods (Schoeneberger et.al., 2002). Digital
<br />photographs were taken of each pit and adjacent landscape. All soil and spoil laboratory
<br />data was reviewed and approved by IML soils laboratory supervisor Ms. Karen Barten.
<br />All soil and spoil samples were analyzed by IML. The analytical pazameters for the soil
<br />backhoe pits included: pH; saturation percent, electrical conductivity (EC); sodium
<br />adsorption ratio (SAR calculation from meq/L for calcium, magnesium, and sodium);
<br />texture (percent sand, sih, and clay - by hydrometer method), and NPK (nitrate-nitrogen,
<br />phosphorus, and potassium, ppm). The overburden spoil samples from the backhoe pits
<br />were also analyzed for these parameters, except phosphorus and potassium, as well as
<br />Boron (B), Selenium (Se), and acid-base potential (ABP) which included sepazate
<br />analysis/calculation for: total sulfur percent, total sulfiu acid-base (tons/1000 tons),
<br />neutralization potential (tons/1000 tons), total sulfur acid-base potential (tons/1000 tons),
<br />and pyritic sulfur acid-base potential (tons/1000 tons) for any samples with a total sulfur
<br />ABP of less than minus five (<5.0). The analytical parameters for the "final regraded
<br />spoil" samples included pH, EC, SAR, saturation percent, texture, nitrate-nitrogen, and
<br />ABP.
<br />All field and laboratory data were evaluated for suitability based on standazd threshold
<br />values for significant parameters, primarily EC, SAR, and AB potential. References for
<br />suitability evaluation include "Criteria for Evaluating Overburden, Underburden, and
<br />Regraded Spoil Suitability" (Seneca Coal IIW Mine, Table 6-3, revised January 2002),
<br />and "Criteria to Establish Suitability of Topsoil, or Topsoil Substitutes, and Overburden"
<br />(Wyoming Department of Environmental Quality, Tables I-2 and I-4, revised
<br />November1996). Unsuitable values include pH (<5 or >9), saturation percent (<25 or
<br />>85), electrical conductivity (EC>12), sodicity (SAR >18 or 22 depending on clay
<br />texture), and nitrate-nitrogen (>60ppm). Clay, sandy clay, or silty clay texture with
<br />greater than 50 percent clay content is also considered unsuitable except with
<br />amelioration (Seneca Coal II W Mine, 2002).
<br />3.0 RESULTS
<br />Reaoolied Topsoil and Regraded Saoil Laboratory Results:
<br />Several sets of laboratory data are attached to this report. Set 1 samples were delivered to
<br />IML on March 29 and reported on April 13, 2006. They include 3 final-grade spoil
<br />samples from Yoast (Yoast #1 thru #3) and 3 from 2W (2W #l thru #3). Set 2 samples
<br />were delivered on May 11 and reported on May 30, and include 3 final-grade spoil
<br />samples from Yoast (Yoast #4 thru #6) and 3 from 2W (2W #4 thru #6). Set 3 samples
<br />were delivered on June 9 and reported on September 26, and include 8 final-grade spoil
<br />samples from Yoast (Yoast #7 thru #14) and 3 from 2W (2W #7 thru #9). Set 4 samples
<br />were delivered on August 9 and reported on September 13, and include 10 final-grade
<br />• spoil samples from Yoast (Yoast #15 thru #24) and 16 from 2W (2W #10 thru #25). Set 5
<br />samples were delivered on October 6 and reported on November 2, and include 8 final-
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