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D-7 <br /> The eolian sand deposit to be mined is a result of wind erosion(deflation),transport,and re-deposition, <br /> largely via saltation and/or creep processes. The Keenesburg No. 2 Mine sand deposit is on the <br /> northeast flank of the Denver Basin where the underlying sedimentary rocks,comprised of sedimentary <br /> units that dip generally to the south and southwest at about 50 to 100 ft. per mile. The immediate <br /> underlying strata are comprised of the upper and lower units of the Laramie Formation, respectively, <br /> with the uppermost part consisting of 250 to 600 ft.of shale,siltstone,claystone,occasional sandstone, <br /> and minor coal. Below this,the lower unit is comprised of an approximately 100 to 300 ft.thick zone <br /> of sandstone,shale,and coal. (Kirkham and Ludwig; 1979). <br /> It is anticipated that pit floor conditions will readily support mining operations with the type(s) of <br /> equipment to be employed. Where minor, isolated saturated lenses are or may be encountered within <br /> the deposit, it is anticipated that free drain-down (e.g., infiltration) will naturally occur and/or that <br /> conditions can be addressed through temporary routing of such seepage to low-lying areas within the <br /> active mining pit depression. <br /> With respect to the more general localized groundwater conditions, it is well known that the (deeper) <br /> Fox Hills Sandstone and the Laramie Formation, which are typically considered/combined into a <br /> singular hydrogeologic unit,are considered a principle aquifer of the Denver Basin,with the sandstones <br /> in both units considered aquifers. However,the upper part of the Laramie Formation is considered a <br /> confining unit, and it is anticipated that all mining(of the surficial eolian sand)will remain well above <br /> (i.e., several hundred feet), and will not penetrate, the upper part of the Laramie Formation. Locally, <br /> economically exploitable aquifers are present at depths in excess of 500 to 600-ft.(as demonstrated by <br /> groundwater well logs);comparatively,mining at the Keenesburg No.2 Mine is anticipated to terminate <br /> at or above a nominal 30 ft.to 40 ft.below ground surface. <br /> (g) Identify the primary and secondary commodities to be mined/extracted and describe the intended <br /> use; <br /> The primary commodity to be mined is an industrial sand product to be utilized within the regional oil <br /> and gas industry sector. <br /> There is no immediately foreseen market for any off-specification, reject, or wash product waste <br /> materials that will be generated as a result of the processing operations;however,CSC retains the right <br /> to market any or all such materials if economic conditions warrant doing so. CSC envisions that any <br /> Keenesburg No. 2 Mine_112 Reclamation Operation—November 22, 2019 <br />