2024-02-01_REVISION - M1973021 (2)

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Ninth Technical Revision (TR09) to Permit M-1973-021, Holcim- WCR, Inc. Morrison Quarry January 2024 | 5 Surface water runoff and stormwater entering the South Quarry will continue to be managed as prescribed in AM07, with the exception of modifications to the South Quarry West Wall drainage design (a Phase II Drainage Report was submitted as an appendix to AM07). To manage surface water runoff from the reclaimed South Quarry West Wall, Holcim will divert stormwater from the reclaimed slope of the south quarry highwall above elevation 7,110 ft in a diversion channel. The diversion channel will direct flows away from the highwall. The diversion will flow north parallel to the highwall along an inactive bench at a mild slope and then travel down a steeper chute slope, referred to as the diversion channel chute, to outlet to the South Quarry drainage area along the installed west quarry haul road. The drainage diversion structures were sized based on calculated 100-year peak flow rates and runoff volumes to limit impacts to reclaimed areas and existing drainage infrastructure. The drainage channel along the South Quarry West wall is a permanent feature and its final configuration can be found on Exhibit F.1. The diversion channel chute is a temporary feature that will be removed or modified as the West Quarry mine plan progresses. The updated design will be completed at a later date. Attachment B presents the detailed design for the South Quarry West Wall drainage. Schedule for Satellite South Pit Buildout Phase III development schedule remains unchanged. The West Quarry will be mined concurrently with the Satellite South Pit. The Satellite South Pit is anticipated to take up to three years to complete.