2010-05-25_REVISION - C1981008 (4)

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this area is as follows: Since Lift A thicknesses are from 6 -13 inches and Lift B thicknesses are also relatively shallow (8" to 22 "), Lift A and B will be combined into one lift of mixed topsoil because it is very difficult to strip thicknesses of approximately 6 -8 inches with such large mining equipment. The Survcadd thickness averages for the non prime farmland fields west of the pit in February 2008 show 7.10 inches for the average of Lift A and 17.40 inches of Lift B. Using 80% of the soil sample average to obtain a stripping average for the area, this results in 5.7 inches for Lift A and 13.9 inches for Lift B. Therefore, the total average stripping thickness for the combined Mixed Topsoil ( Lift A and Lift B) is 19.6 inches. The expected range is from 8 inches to 38 inches. The mine foremen and operators will be trained on the stripping of the mixed Lift A & B, and will know to stop the removal when coarse fragments have a rise from less than 10% volume in Lift B to material that has significantly higher coarse fragments (20 -25 %). In some cases, bedrock will be encountered at the end of Lift B in the non prime farmland areas. An additional amount of suitable subsoil, which is basically the Bench 1 overburden material, will be stripped and placed as shown on Map 2.05.4 -4. The Benson West property basically has already been backfilled with a minimum of 30 inches of this material. The Lloyd property will receive a minimum of 30" of this material and the WFC property will receive a minimum thickness of 24" of this Bench 1 material. This backfilled Bench 1 material was tested in April of 2008 for the eastern area of the Morgan property which was exposed that time, and the results showed that it meets the suitability criteria. For the purposes of the volume calculations, the suitable subsoil material on the Benson West is assumed to be 30" in thickness, and Lloyd property is 30" and the WFC property will be 24" in thickness. These amounts allow a minimum of 48" total suitable medium on the Benson and Lloyd properties and 44" on the WFC property. From the 1998 soil survey, the Bench 1 suitable material is differentiated from the bottom of Lift B (which is the C soil horizon) by greater percentage of coarse fragments. The C horizon (at the bottom of the combined Lift A & B) generally has less than 10% coarse fragments and the Bench 1 material has from approximately 15% to 30 %. Lower material with higher coarse fragment amounts is considered overburden and will be placed below the suitable subsoil material. The mine foreman and the equipment operators will be trained to differentiate these levels of coarse fragments. (Revised October 09) 2.04.9 -35