2018-03-09_PERMIT FILE - M2017049 (29)

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Transit Mix Concrete Co. evaluating the stability of the fines stockpiles. The factors of safety for both the pit walls and fines stockpile exceed those required by the Division.These evaluations were included in Exhibit 6.5 of the permit application. Additional details on the geotechnical analysis and responses to comments from Trout Unlimited are included in the attached memorandum from Norwest Corporation. Objection: The objector claims application does not adequately demonstrate that disturbances to the hydrologic balance will be minimized. Specific claims include that the application does not prove there is no interconnection of fractures north and south of the creek and that the granite fractures do not feed wells east of the fault(presumably in the sandstone aquifer). Response: The groundwater assessment and impacts analysis included in Attachment G-2 of Exhibit G discusses in detail the groundwater resources in the Little Turkey Creek watershed and quantifies the water balance. All operational water for HRR will be purchased from Colorado Springs Utilities that will be trucked to the site as needed. Local ground and surface water sources will not be developed for operational water usage. Any groundwater that flows into the HRR quarry will be collected in ditches and directed to sediment detention basins before being released into Little Turkey Creek,the ultimate discharge point for natural groundwater flow in this area. Post mining groundwater interception will flow to Little Turkey Creek via the post-mining reclaimed drainage topography. From a water balance perspective,there will be no net loss to the water resources of the Little Turkey Creek watershed during the active mining and post-mining periods. With regard to specific claims,the groundwater report included as Attachment G-2 in Exhibit G specifically addresses both of these topics. The most active groundwater flow in the granitic rocks is within the more highly fractured zone underlying the Little Turkey Creek valley bottom. Potentiometric data and water balance considerations clearly show that the Little Turkey Creek valley forms the major flow path for groundwater to cross the fault zone separating the granitic bedrock to the west from the Fountain Formation sedimentary rocks to the east. Little Turkey Creek is a gaining creek west of the "West Fault" and is the discharge zone for groundwater from both the north and south valley sides. The Little Turkey Creek valley bottom forms a hydraulic divide for the watershed groundwater flow system. The fracture interconnection between the north and south of the creek do not influence the groundwater flow path within the watershed. The HRR quarry base is designed to be maintained at least 10 feet above, and 100 feet outside,the adjacent Little Turkey Creek drainage. This ensures that the quarry will not impact the essential hydraulic functions of the valley bottom as a discharge point for groundwater and a conduit for groundwater flow to cross the fault zone and recharge the Fountain Formation to the east. There is clear potentiometric evidence demonstrating that groundwater flow within the south ridge area,where the quarry will be located, is towards the Little Turkey Creek valley bottom where it either discharges to Little Turkey Creek surface flows or flows parallel to the valley within the fracture zone underlying the valley bottom. The Little Turkey Creek Valley bottom provides the major flow path for groundwater to cross the fault zone. Recharge to the Fountain Formation on the east side of the fault zone is provided by Little Turkey Creek surface water flow and groundwater underflow within the fracture zone underlying the valley bottom. This is supported by the fact that Little Turkey Creek is a Hitch Rack Ranch Quarry Response to Comments March 9,2018 21