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Exhibit D Additional Info <br />Hydrologic Analysis <br />A hydrologic analysis was conducted by Steve Harris of Harris Water Engineering, Inc. (see <br />Exhibit G of original submittal). Mr. Harris' report suggests that groundwater levels will not <br />be significantly affected upon completion, but it does not address the affects of the dewatering <br />that may occur during pit operation. The dewatering of the pit area will likely result in a small <br />cone of depression around the project area. Keyah Grande will monitor both groundwater <br />levels and stream flows during the operation of the pit. Any mature cottonwoods or wetland <br />areas that might be affected by the temporary draw-down will be monitored for signs of stress. <br />Cottonwoods and wetlands that are located close to the project area will be periodically <br />watered with the water that is pumped out of the pit. If the surrounding vegetation shows <br />horticultural signs of stress, or the stream and groundwater data demonstrates that there is a <br />significant affect (greater than 1.5 standard deviations from the long term monthly mean) then <br />remedial action will be taken to correct the dewatering plan. Furthermore, upstream and <br />downstream flows and water quality will be monitored. <br />Floodplain Boundaries <br />The floodplain of Devil Creek has not been mapped, but the physical indicators observed <br />onsite, including steep topological breaks, fluvial morphology, and vegetative community age <br />and composition, provide a fairly accurate means of mapping the floodplain of Devil Creek. It <br />is apparent from these indicators that the almost the entire project is located with the expected <br />100-year flood zone. The only area that may be high enough to avoid a 100-year flood is the <br />southeast side of the project area where the stockpile areas have been relocated. The site is <br />likely to see the highest flows during the spring run-off. During this time special precautions <br />will be taken to prevent the loss of material and soil. Specifically, all BMPs will be re- <br />enforced and stored materials will be removed from flood prone areas. SME has identified two <br />locations where Devil Creek may jump its banks during a flood event. These areas will be <br />fortified with rip rap or other temporary scour and bank erosion protection. The reclamation <br />plan has been designed in a manner that will not only accommodate future flood events, but <br />will actually help to abate the events by increasing floodplain capacity and wetland vegetation. <br />Pit High walls <br />The slope to which the highwalls of the pit will be mined will depend on the stability of the soil <br />profile. At no time will the slope of the highwalls exceed a 1:1 slope. Furthermore, the operator <br />will maintain compliance with all applicable MSHA standards in order to guarantee the safety of <br />the workers. Lastly, in accordance with Section 3.1.5 (7) of the Mineral Rules and Regulations <br />of the Colorado Mined Land Reclamation Board for the Extraction of Construction Material (as <br />currently amended) the pits will need to be reclaimed to a 2:1 side slope (3:1 near the top of the <br />pit), therefore it would not be practical to exceed the 1:1 slope limit during operations due to the <br />cost and time it would require to restore the slopes upon completion.