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Ninth Technical Revision(TR09)to Permit M-1973-021,Holcim-WCR,Inc. Morrison Quarry <br /> Groundwater Management <br /> Groundwater measurements in and around the proposed Satellite South Pit identify groundwater <br /> levels between El. 6,588 and El, 6600. These water levels and locations are presented in Table 1. <br /> Table 1: South Quarry Water Level Measurements <br /> Well ID/Boring # Location 2022 Water Level <br /> Elevation ft <br /> MW-2019-02 South of the South Quarry 6,588 <br /> HDR-001 P Current South Quarry it floor El, 6,600 6,595 <br /> HDR-002 Current South Quarry it floor El, 6,600 6,588 <br /> HDR-003 Current South Quarry it floor El, 6,600 6,592 <br /> HDR-004 Current South Quarry it floor El, 6,600 6,600 <br /> These water levels indicate that Holcim will need to manage groundwater as the Satellite South Pit is <br /> advanced. To evaluate potential groundwater in-flows, HDR conducted a hydrogeologic analysis, <br /> using acoustic televiewer and flowmeter tools, to evaluate fracture networks and flow rates at four <br /> observation holes within the South Satellite Pit footprint. Flows in these borings were low, ranging <br /> from 0.01 to 0.19 gallons per minute under ambient flow conditions. Using this flow data and the <br /> planned Satellite South Pit geometry, it is estimated that approximately 5 gallons per minute of water <br /> would potentially require management during mining operations. <br /> To manage this anticipated groundwater, as mining proceeds in the South Quarry, mining operations <br /> will proceed from east to west, creating a low point on the east side of the pit, south of the spur road. <br /> a sump will be maintained in the pit where accumulated groundwater will be pumped and either(1) <br /> discharged to Outfall 006 (directly east of the proposed sump location); (2) used directly on site; or <br /> (3) stored on site and evaporated. <br /> Concurrent with this TR, Holcim is preparing a water court application (including an application for a <br /> plan for augmentation), substitute water supply plan, and well permit application to allow for the <br /> interception of groundwater and to replace depletions from the interception, exposure, storage, and <br /> use of groundwater. Until the substitute water supply plan and well permit are granted, if <br /> groundwater is encountered during mining, operations will cease in that area and the excavation will <br /> be backfilled. It is anticipated that Holcim will not obtain a decree in the water court case for at least <br /> one to two years after the water court application is filed. <br /> Surface Water and Stormwater Management <br /> Surface water runoff and stormwater entering the South Quarry will continue to be managed as <br /> prescribed in AM07, with the exception of modifications to the South Quarry West Wall drainage <br /> design (a Phase II Drainage Report was submitted as an appendix to AM07). To manage surface <br /> water runoff from the reclaimed South Quarry West Wall, Holcim will divert stormwater from the <br /> reclaimed slope of the south quarry highwall above elevation 7,110 ft in a diversion channel. The <br /> diversion channel will direct flows away from the highwall. The diversion will flow north parallel to the <br /> highwall along an inactive bench at a mild slope and then travel down a steeper chute slope, <br /> referred to as the diversion channel chute, to outlet to the South Quarry drainage area along the <br /> October 2023 1 4 <br />