2012-08-24_GENERAL DOCUMENTS - C1981008 (2)

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GSM's concern that Bench 1 material may not be a suitable substitute for Lift B material seems to be primarily based on the EC and rock content of this material. Bench 1 material was sampled in TP06, TP07 and TP08 in the Substitute Subsoil Redistribution Area at three different depths. The suitability criteria for Bench 1 material is very similar to the Lift B material. According to Map 2.05.4 -6 Morgan Property Topsoil Replacement Plan as of June 2010, Bench 1 material has been used as subsoil in Zone 1 on the eastern portion of the property. TP06, TP07 and TP08 are located in Zone 1. Based on the data, the Bench 1 material was within the threshold limits for all of the parameters. The EC threshold for Bench 1 material in Zone 1 is 6mmho /cm, the EC found in these test pits were 4.4, 5.0 and 4.3 mmho /cm. Rock fragments measured in the Bench 1 material was well below the threshold level for Lift B and Bench 1 material. If the EC threshold was lowered to 4mmho /cm, similar to item #2 above, it is likely the soils could be managed to account for the excess salt content of the soil. 4.) OSM's review has determined that the practice of significantly mixing C horizon material of inadequately proven quality with prime B horizon soils for creating the B lift substrate for prime farmland reclamation contravenes the requirements at 2.06.6(2)(d), 2.06(4)(c), 4.06.2(3), 4.25.3(2), 4.25.4(4). Overall this issue is similar to item #1 above; it does not appear the stockpiles material was significantly contaminated with C horizon material. Apossible exception to this is the elevated levels of Electrical Conductivity (EC) within the stockpiles. The stockpile data would indicate the EC levels in the stockpiles is higher on average than in the undisturbed area. The average EC found in the horizons of the undisturbed areas (including lower B and Upper C horizons) in TPO1 -TP05 yielded EC values of 4.22, 1.92, 1.32, 2.36 and 4.16 mmho /cm for each of the test pits. Sample Pile's A, B, C, D, and E yielded an average EC of 3.68, 3.71, 4.10, 4.21 and 3.46mmho /cm respectively. Based on the 1998 IRI soil survey samples and the 2011 samples from the undisturbed area on the Morgan property, it does not appear EC levels were as high as the level's found in the soil stockpiles even within the lower B and C horizons. Given this, it is unlikely the C horizon significantly affected the EC of the lift B material. Based on the analysis of Sample Pile B, this lift B material does meet the suitability criteria approved in the permit. Given the parameters required for a soil to classify land as prime farmland as discussed above, depending on the rooting zone of the plants to be established on the site and the depth of the lift B material to be placed, it may be necessary to revise the threshold for Lift B material to 4mmho /cm. If the EC threshold level was decreased to 4mmho /cm, only a portion of Lift B material would be outside of the acceptable limit. The overall EC average for the lift B material was measured to be less 4mmhos /cm, but any excess salts could be managed during reclamation and future farming practices. The question becomes, what would cause the EC values to be different on average between the undisturbed material and the stockpiled material? Electrical conductivity in soils is a function of precipitation, evapotranspiration, irrigation techniques, irrigation water quality and the properties of the soil material. The EC levels vary inconsistently throughout the soil profiles of the undisturbed land that the elevated EC levels of the soil stockpiles cannot be tied conclusively to the mixing of C horizon material with other horizons. Perhaps the function of stockpiling this material exposes the soil to an increased amount of evaporation leaving an increased amount of minerals in the soil increasing the EC level. Spraying water on the stockpiles with even low salinity could result in salt accumulation within soil stockpiles according to research (Page 25, Guidelines for Mining in Arid Environments; Department of Minerals and Energy; Western Australia, 1996). It is unclear what would cause the EC values to be different on average between the undisturbed material and the stockpiled material. 5.) Instead of receiving the balance of the B horizon soils salvaged from Zone 4, which had been previously identified as prime soils by the NRCS, as a substitute Zone 4 is to receive a mixed (50150) layer of C and B horizon materials as the B lift for reclamation. As per OSM's review of the permit, this substitution was approved by DRMS without demonstration that the substitute has Page 7 of 10