2024-01-31_REVISION - M1977344 ‎(28)‎

• Permit No: M1977344
• IBM Index Class Name: Revision
• Doc Date: 1/31/2024
• Doc Name Note: App 4.6 Red Creek Quarry Modeling
• Doc Name: Adequacy Review - Preliminary
• From: Holcim
• To: DRMS
• Type & Sequence: AM2
• Email Name: TC1
• Email Name: MAC
• Media Type: D
• Archive: No

Red Creek Quarry, Groundwater Modeling Analysis

ii
DRAFT for review purposes only. Use of contents on this sheet is subject to the limitations specified at the beginning of thi s document.
RedCreekQuarry_Modeling_TM_DRAFT_20230911

Table of Contents
List of Figures ............................................................................................................................................................ ii
List of Tables ............................................................................................................................................................. iii
List of Abbreviations ................................................................................................................................................. iv
Section 1: Introduction ............................................................................................................................................. 1
1.1 Model Objectives ............................................................................................................................................. 1
1.2 Background ...................................................................................................................................................... 1
1.3 Site Conceptual Leapfrog Model .................................................................................................................... 3
1.4 Mine Plan Operations ...................................................................................................................................... 3
Section 2: Model Construction ................................................................................................................................ 5
2.1 Modeling Codes and Discretization ................................................................................................................ 5
2.2 Model Layering ................................................................................................................................................ 7
2.3 Hydraulic Boundary Conditions ...................................................................................................................... 7
2.4 Hydraulic Properties ........................................................................................................................................ 7
2.5 Groundwater Recharge and Storage .............................................................................................................. 7
2.6 Red Creek ........................................................................................................................................................ 8
2.7 MPO Mine Blocks .......................................................................................................................................... 10
Section 3: Simulation Results ................................................................................................................................ 10
3.1 Calibration to Existing Conditions ................................................................................................................. 10
3.2 Projected MPO Mine Block Groundwater Accumulation ............................................................................. 12
3.3 Projected MPO Mine Block Creek Influence ................................................................................................ 13
Section 4: Summary and Conclusions .................................................................................................................. 14
Section 5: Recommendations for Model Improvements ..................................................................................... 14
Section 6: Limitations ............................................................................................................................................ 14
References .............................................................................................................................................................. 15

List of Figures
Figure 1. Red Creek Quarry Site Map. ..................................................................................................................... 2
Figure 2. Red Creek Quarry MPO Mine Blocks. ...................................................................................................... 4
Figure 3. Red Creek Quarry Model Domain. ........................................................................................................... 6
Figure 4. Red Creek Reaches Groundwater Flow Model. ...................................................................................... 9
Figure 5. Red Creek Quarry Existing Conditions Simulated Groundwater Elevation Contours (feet). ............... 11