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Exhibit C-3A where estimated bedrock contours are shown, based on drilling information. Of course the <br />contours are only approximations, but what was found in Phase I was reasonably close to what <br />predictions said would be [here. Therefore, it can be assumed that the bedrock contours in Phase 2 are <br />probably close to being representative of what is actually there. <br />Underneath the gravel deposit is the Pierre Shale. This formation commonly occurs in this area, <br />as welt as throughout eastern Colorado. This formation forms the bedrock and the erosion surface before <br />the extensive sediment deposition during the Pleistocene. Another formation that is sometimes found <br />under these gravel deposits besides the Pierre Shale is the Carlisle Shale. These two formations are very <br />similar and for [he purposes of this plan need not be distinguished. The Carlisle is considered [o be <br />younger than [he Pierre and therefore, where it occurs, rests on [op of the Pierre. The groundwater in [he <br />alluvium above the shale is restricted [o a strong horizontal flow component with very little seepage <br />downward into the shale. This shale does not present any difficulties with respect to its chemistry or <br />physical properties. It does tend to fragment into thin, flat pieces when exposed to the air for some time, <br />but this does no[ appreciably alter its properties. Because these shales are quite dense, few zones in these <br />deposits act as reliable aquifers. On the other hand, when exposed [o the surface and combined with <br />suitable organic material after extensive weathering, they can form some of the richest agricultural soils in <br />Colorado. <br />Pre-Mining Issues of Importance <br />Prior to describing the actual mining plan, a number of issues need to be addressed that pertain to <br />the overall conduct of the operation. These include a definition of what constitutes the permit boundary <br />and [he affected land boundary so it is understood where disturbances can and cannot be made. Next is a <br />consideration of the impact of the operation on the groundwater surrounding the mine. And last is the <br />general approach to and consideration of the impacts of dewatering. A thorough understanding of these <br />issues is necessary to appropriately implement [he mining while minimizing impact on surrounding lands. <br />Permit Area and Affected Land Area <br />PERMIT AREA: <br />Requirem enr: The only land that may be disturbed within the large permit area is [hat land <br />contained in Phase 1 and Phase 2 as shown on the maps in Exhibit C. <br />Pueblo East Pit Amendment 3 (2007) Exhibit D Page 11 of 34 <br />