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buried with a minimum of three feet of suitable spoil prior to soil replacement. <br />Reareded Sooil Honitorina Proarem. In order to provide a feedback system to check the <br />reliability of the overburden sampling and analysis program, a regraded spoil sampling <br />program will be initiated. A sampling plan will be used in the Wedge area where the <br />overburden is thicker then 60 feet (as shown on Exhibit 6-4) and in the entire Wolf Creek <br />area to identify final graded areas having an unsuitable clay, pH, boron, end/or acid base <br />potential level. Prior to soil replacement, final graded areas will be sampled with a <br />hydraulic soil sampler, backhoe, bucket auger, or other suitable equipment. One <br />representative sample from a vertical increment of 0.0 to 3.0 feet will be collected by or <br />under the supervision of a soil scientist from a 60 degree slant grid system wiCh 500 foot <br />centers in the Wedge area end 300 foot centers in the Wolf Creek area. The soil scientist <br />will also inspect the su rf ec e~spoil between grid points. If a significant change in spoil <br />characteristics is observed between grid points, additional sample sites will be located. <br />Regraded spoil will also be visually inspected for compaction, possible root growth <br />problems, end the potential for slippage et the soil/spoil interface. <br />Shallow postmine soil pits will be excavated near revegetetion monitoring sites to • <br />evaluate plant rooting characteristics end compare topsoil/spoil date with site-specif it <br />revegetetion data. Semple sites will typically be placed in three-year-old revegetetion <br />areas et a frequency of about 1 site per 40 acres. Pits will be excavated end soil and <br />spoil will be sampled to a minimum depth of four feet. <br />Ai a minimum, final graded spoil samples will be analyzed for the following parameters to <br />determine suitability: pH, particle sire, boron, acid base potential, end saturation <br />percent. The parameter list is based upon the baseline information acquired during the <br />premine overburden (Tab 6) end soil survey (Tab 9) sampling programs. <br />The parameter list will be more closely evaluated once sufficient samples are collected to <br />determine the degree of sample variability. This approach will help to eliminate <br />unnecessary end unwarrantable analyses cost and data duplication. this parameter list <br />represents those characteristics of the Yoest soil end overburden which may hinder plant <br />growth on regraded spoil. Laboratory procedures and suitability criteria will be <br />identical to those described in Tab 6, Tables 4 and 5, and Tab 9, Tables 1 and 2. <br />U <br />i <br />bl <br />S <br />il Mi <br />i i <br />l <br />f h <br />i <br />bl <br />f <br />l <br />i <br />hi • <br />nsu <br />ta <br />e <br />oo <br />t one or more <br />aet <br />on P <br />an. I e unsu <br />ta <br />e <br />parameters <br />el <br />w <br />t <br />n t <br />range et a Biven grid point, a four-part mitigation plan will be implemented. <br />4 Revised 03/01/95 <br />