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MINING PLAN <br />(Exhibit C-3) located on the west side of the former reservoir site, removes groundwater from the <br />upper water zone; the lower water zone does not exist in this area. Pipelines from the extraction wells <br />convey the water to the treatment plan for treatment. The treated water is then reinjected into the <br />lower water zone along Bradley Road just east of Academy Boulevard. <br />The portion of the sand deposit to be mined is all above the clay seam that separates the two <br />water zones. Actually mining will stop a few feet above the clay seam as described later in this mining <br />plan. <br />Generally the sand on the norkhem end of the Little Johnson azea and mostly outside the plume <br />of affected water is more coarse than the sand on the southern portion of the mining area. Thus mining <br />on the north end of the area will probably be more complete than the mining on the southern end of <br />the area. But the mining plan map (Exhibit C) shows the extraction to be Fairly even in depth across <br />the mining area. This equalized extraction plan is used because it is known that the sand deposit was <br />variable where it has been mined in Phase 4e. Insufficient data is available from the Little Johnson <br />area to actually determine whether there are pockets of more coarse sand on the south end. Therefore, <br />the mining plan assumes that all of the sand to the designed maximum depth will be removed, even <br />though it is possible less will be removed on the south end than the north end of the mining area. <br />The sand deposit itself is a blend of both alluvial and aeolian sands. Structure in the sand <br />deposit clearly shows fairly continuous layers of sand of varying texture and thickness. This indicates <br />a primary deposition by alluvial processes. Cross-bedding as seen in sand dunes is faint or absent. <br />Undoubtedly though some of the sand was blown around on the dry land adjacent to the meandering <br />water course, but aeolian sand constitutes a fairly minor amount of the sand deposit. This sand is <br />probably of Pleistocene age and was probably deposited by Fountain Creek when it flowed across a <br />broad outwash plain from the Pikes Peak area when the glaciers on the north and east sides of the <br />mountain were melting. Undoubtedly, Monument Creek flowing southward from the Palmer Divide <br />as well as other drainages such as Sand Creek contributed to the deposit. The layering in the sand <br />deposit clearly indicates periods of vigorous erosion that deposited small amounts of gravel. These <br />were mixed with periods of gentle flows that deposited mostly fine sand. The shape of the Pierre <br />Shale bedrock in the valley indicates the presence of at least one major paleo-channel in this area. <br />Section LJ-1 at the end of this exhibit shows across-section through the Little Johnson area <br />along a basically west to east line. The zonation in the cross-section was derived from a compilation <br />of data derived from a large number of exploratory drill holes, water treatment process drill holes, and <br />monitoring well drill holes. However, because the various drill holes were not done at the same time <br />or by the same people and were not logged by the same person, differences in the interpretation of the <br />data obtained from the drill holes introduce some inconsistencies, especially with regard to the actual <br />texture of the sand encountered. However, water levels and other major features such as the clay <br />seam, when present, and bedrock are highly consistent between the drill holes. For those critical <br />features of the structure that relate to the remediation program, the drill holes aze considered to be <br />Daniels Sand Pit #2 -Little Johnson Amendment - M-~s~3-oo~ Exhibit D Page 2 <br />