2012-03-07_PERMIT FILE - C2010088A (17)

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2.04.6 Geology Description (3) Underground Mining (a) The proposed loadout is within the historic floodplain of the Colorado River. Within the permit area the uppermost 15 to 23 feet is described in the Gary Refinery well logs as silty clay "slopewash" from sheet flow. This deposit is most likely a combination of windblown fine material, slopewash, and possibly overbank flood deposits. Underlying the silty clay is 19 to 25 feet of alluvium that consists of poorly to well sorted sand and sandy gravel that forms the alluvial aquifer. (i) Not applicable to the loadout operation. (ii) Not applicable to the loadout operation. (iii) Not applicable to the loadout operation. (iv) Not applicable to the loadout operation. (v) (A) The near - surface strata beneath the disturbed area is described in the well logs as silty clay " slopewash" from sheet flow. (B) The near - surface strata is silty to sandy clay loam. The acid forming potential of the overburden and coal can be measured by the Acid Base Potential (ABP) of a sample. According to `Applications of Environmental Chemistry., A Practical Guide for Environmental Professionals" the acid base potential is equal to the equlivalents of Calcium Carbonates in excess of the amount needed to neutralize the acid that could potentially be produced from oxidation of pyritic sulfur. The acid base potential of the near - surface strata ranges from 19 to 246. Thus, the near - surface strata does not have acid forming properties. Additional analyses of the near surface strata are presented in Volume I, Exhibit 6. The analyses referenced above are samples obtained for test pits (TP) 3, 4, 6 & 7 ( "A" through "D" in the spread sheet in Exhibit 6). The near surface samples were obtained from a depth of 1.5 to 6 feet. The location of the test pits are shown on Map 19 Previously Disturbed Areas. Permit Application 2.04 -11 04/11