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reasonable potential to achieve equivalent yield potential when compared to the 31 inches of lift B <br />(100% B horizon) that existed prior to mining disturbance in Zone 4. Therefore, OSM's review has <br />determined that this soil handling practice does not comply with the State's regulations at <br />2.06.6(2)(d), 2.06(4)(c), 4.06.2(3), 4.25.3(2), 4.25.4(4). <br />This issue is similar to Item #2 above, without pre - mining and post mining yield numbers it would be <br />difficult to ascertain if the "substitute" material will restore the property to its pre - mining yield. Based <br />solely on the approved suitability criteria and the soil samples tested, it would appear the Lift B material <br />has not been significantly impacted by mixing of the soil horizons. Also as discussed above, a possible <br />exception to this is EC levels. <br />6.) Considering that the B and C horizons are approved for salvage in a combined (mixed) lift, and <br />that the limited sample data available indicated the C Horizon materials don't appear to have <br />reasonable potential for re- establishing the yield capability of the Morgan's prime farmland, it <br />appears there is significant risk that the reclamation plans may be unsuccessful. Additionally, <br />should the redistributed soil and substitute materials be found to be unsuitable through the <br />currently approved practice of sampling respread materials instead of sampling prior to <br />redistribution, mitigation of the resulting impacts may be impractical due to the extensive mixing of <br />A, B and C horizon and overburden materials approved for use. The practice of after - the -fact <br />sampling could lead to loss of a significant portion of the prime soils (a protected natural resource), <br />should use of the substitute materials not meet suitability criteria and/or agricultural yield <br />standards, as the respread materials may require burial, as discussed in the permit. Based on the <br />lack of a demonstration or affirming that the reclamation plan approved will reasonably conclude <br />with success, OSM's review finds that the after - the -fact soil/spoil sampling practice approved in the <br />permit, is not in compliance with 2.04.9(1)(d) and 2.06.6(2)(a)(ii). <br />The lab result data for each of the stockpiled material was analyzed and compared to the currently <br />approved suitability criteria. The results of this analysis is discussed above. Based on this data, it would <br />be inappropriate to bury soil and substitute material if the material does not meet all of the suitability <br />criteria. Given the data, the stockpiled material does not appear to have been significantly impacted by <br />the mixing of the various soil horizons with the possible exception of the EC levels as discussed above. <br />Since the salvaged soil has been sampled and analyzed, a soil quality mitigation plan and/or soil <br />amendment plan should be created for the stockpiles with parameters found to be outside of the soil <br />suitability criteria. <br />7.) The suitability criteria for the soil and substitute materials have been altered with the approval <br />of PR -6 (i.e. from 4mmho /cm to 6mmho /cm). According to Colorado State University Extension <br />Bulletin Number .503, Managing Saline Soils, a replaced growth medium that allows an EC of <br />6mmhos /cm has strong potential to be toxic to corn as well as have detrimental impact to Alfalfa <br />production and forage crops.... Considering that alfalfa is the target crop for demonstrating the <br />yield capability of the reclaimed prime farmland and that corn is likely to be a primary rotational <br />crop after the land is returned to the landowner, approval of an EC threshold of 6 mmhos /cm for <br />affirming the quality of the growth media to be used for reclamation is not in compliance with <br />regulations 4.05.8(1), 2.06.6(2)(d), and 4.06.5(4)(a) of the Colorado State Program. <br />Electrical Conductivity levels in the stockpiled soil material is of concern. Table 2.05.4(2)(d) -lA; lists <br />the Spoil and Soil suitability criteria for Morgan property. Lift A and Mixed topsoil must have an EC <br />level below 4mmho /com. Lift B Material must have an EC level below 6mmho /cm. In accordance with <br />National Soil Survey Handbook Chapter 657.5, to be considered a prime farmland soil, "the soil can be <br />managed so that, in all horizons within a depth of 40 inched (1 meter) or in the root zone if the root zone <br />is less than 40 inches deep, during part of each year the conductivity of the saturation is less than <br />Page 8 of 10 <br />