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threshold at depths in excess of 93 cm. Based on how the permit is written, only Lift B material could be <br />salvaged at these depths. None of the soil samples in the undisturbed areas yielded CCE% at or above the <br />Lift B threshold. In terms of rock fragments, none of the horizons sampled in the undisturbed areas <br />yielded level near the set thresholds. <br />A discussion of the CCE% levels found in the stockpiled material is above. Overall, it appears the <br />calcium carbonate levels within the stockpiles is below the thresholds set for the type (Lift A, Lift B, <br />Mixed) of material stockpiled. Very few samples within each pile yielded CCE% levels beyond the <br />designated thresholds. Based on this, it would appear contamination of calcium carbonate from the C <br />horizon is minimal. Also, the rock fragment percentage found both within the stockpiles and all of the <br />soil horizons in the undisturbed areas were well below the designated thresholds. <br />In conclusion, it does not appear the stockpiled soil material was contaminated significantly from possible <br />C horizon material. Lift B material that could be salvaged in the undisturbed area has a potential for <br />higher CCE % levels, however as indicated above, none of the horizons sampled had CCE% above the <br />threshold set for Lift B material. GSM's original concern is correct, excess C horizon material could <br />degrade growth media, however based on the samples taken it does not appear this has occurred in the <br />salvaged material or will likely occur in material that could be salvaged as Lift B material. <br />2.) It has not been determined that the practice of extensively mixing the A and B horizons as <br />opposed to segregating and redistributing the A and B horizons in separate lifts, will not degrade <br />the productive capacity of the growth medium when compared to handling these horizons <br />individually. Therefore, the current approved permit is not in compliance with the requirements of <br />the cited state regulation (4.25.3.1). <br />Based on the data obtained from the soil stockpiles, it would be difficult to ascertain if the mixing of the <br />A and B horizons would impact the productivity of the soil. In order to accomplish this, comparisons <br />would have to be made from crop yields measured prior to mining and yields after reclamation. <br />Comparisons can be made of the chemical and physical parameters measured in each of the stockpiled <br />material and the suitability criteria set for the different types of material. These comparisons are <br />discussed above in the analysis of the stockpiled material. Overall the primary concern identified in the <br />stockpiled material is the Electrical Conductivity (EC) levels. The National Soil Survey Handbook, <br />Chapter 657.5 (Attachment 2.04.9 -4 of the permit) indicates the EC threshold necessary for a soil to be <br />considered classified as prime farmland. According to the handbook, the soil can be managed so that, in <br />all horizons within a depth of 40 inches or in the root zone if the root zone is less than 40 inches deep, <br />during part of each year the conductivity of the saturation extract must be less than 4mmhos /cm and the <br />exchangeable sodium must be less than 15. According to Colorado State University Extension Fact <br />Sheet# 0.503; Managing Saline Soils, soil salinity and electrical conductivity can be managed by various <br />agricultural practices. Based on the review of each of the piles above; stockpiles C, D and the Mixed <br />Topsoil layer (from the eastern end of the Morgan property) and a portion of stockpile A do not meet the <br />currently approved suitability criteria. However, the EC levels within these piles measured from 4.1 to <br />4.21mmho /cm on average. It may be possible to manage the property after reclamation to address the <br />excess salts in the soil to make the soil suitable since the National Soil Survey Handbook only requires <br />soils to meet the 4mmho /cm threshold for part of the year. <br />3.) Regarding the substitution approved within the permit, in the absence of a demonstration <br />documenting that the Bench 1 materials are a reliable source of materials for restoring the yield <br />potential of the prime farmlands that existed prior to mining in Zones 1 and 2, OSM's review has <br />determined that the approved use of this substitute is in violation of sections 4.25.3(2), 2.06.6(2)(d), <br />2.04.9(3), and 4.06.2(3), and 4.06.2(4)(a) of the Colorado state program regulations. <br />Page 6 of 10 <br />