2004-08-19_REVISION - M2003037 (3)

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7) This is additionally confirmed by a letter from Jeff Jeffries, who worked at the Bob Cory Pit and the C. E. Mills pits in the 1960's and 1970's. He remembers that the floor of the pits was 40 to 50 feet below the mesa top and that groundwater was never encountered in the pits. 8) Since the long teen Haldorson operation contemplates mining a portion of the terrace to slopes of 3H:1 V, the operation will then leave a depression in the landscape that can be irrigated as before, with the exception of the sideslopes themselves. An evaluation of the potential impacts of this change to the landscape is in order. In short, the current regime is that during irrigation, the CJ and CJN laterals provide ittigation water to the areas west and south of the site. No imgation occurs on the Spring Creek Mesa east of the site. Much of the water is consumed by the plants or released in evapotranspiration. Aportion of this irrigation water infiltrates into the gravels which then migrates downward toward the Mancos Shale and toward the lower terrace. The water moves within 7 feet of the surface of the lower terrace toward the river. Annual precipitation of 10-14 inches makes the terrace very dry and aeeas that do not get irrigation are usually fairly batten with only drought tolerant grasses and shrubs able to survive. The permit area itself has historically been irrigated. The areas west and south of the permit area cannot be affected by the operation since the groundwater direction is towazd the pit from these areas. No wells exist in these areas and irrigation will continue as it has for decades. The water will continue to migrate as it always has, below the mining operation to the northeast. The removal of irrigation from each mining phase as it is mined could lessen the amount of infiltration into the ground, but this amount is relatively small as compared to the whole Mesa. It is also temporary since irrigation will be re- installed in each phase after mining. Another permanent effect of the plan is that the permanent depression will affect surface water runoff from the site. In other words, there will be no surface water runoff The surface of Spring Creek Mesa is so flat and the rainfall so low that almost all runoff either evaporates, is taken up by the plants or infiltrates into the gravels. For the post-mine depression, this will not change. It could only affect the Haldorson Sand and Gravel Mine 36