2025-08-28_HYDROLOGY - M1983194 ‎(7)‎

• Permit No: M1983194
• IBM Index Class Name: Hydrology
• Doc Date: 8/28/2025
• From: NSI
• To: EPA
• Archive: No

Natural Soda LLC 2024 Project Status Report & Annual Plan of Development
iv January 2025
List of Tables:
Table 1: Monthly Production, Sales, and Inventory Summary in Tons (Confidential) ...... 7
Table 2: Mining Interval Annual and Lifetime Production (Confidential) .......................... 7
Table 3: List and Status of Wells Associated with NS (Confidential) ............................. 17
Table 4: Mine and Process Data (Confidential) ............................................................. 20
Table 5: 2024 18H Surface Subsidence Monument (SSM) Installation ......................... 22
Table 6: NS Water Supply Well Pumpage 2024 ............................................................ 23
Table 7: Historical Comparison with 2024 Water Year Data ......................................... 26
Table 8: Yellow and Piceance Creek Discharge Data up to 2024 Water Year .............. 26
Table 9: Disturbed Acreage ........................................................................................... 31
Table 10: Annual Precipitation in inches (10 Year) ....................................................... 33
Table 11: 2024 Hazardous Waste Disposal Inventory................................................... 37

Table of Appendices:
Appendix A: 2024 Groundwater Analytical Results .....................................................A-1
Appendix B: 2024 Potentiometric Surface Maps (Confidential) ...................................B-1
Appendix C: 2024 Vegetation Monitoring & Reclamation Status Report .................... C-1

List of Appendix Figures:
Appx. Figure B-1: NS Average 2024 Potentiometric Surface A-Groove Aquifer
(CONFIDENTIAL)......................................................................................................... B-2
Appx. Figure B-2: NS Average 2024 Potentiometric Surface B-Groove Aquifer
(CONFIDENTIAL)......................................................................................................... B-3

List of Appendix Tables:
Appx. Table A-1: 89-3 Annual Perched Aquifer ............................................................ A-2
Appx. Table A-2: MMC-IRI-1 Annual Perched Aquifer ................................................. A-3
Appx. Table A-3: MMC-IRI-5 Annual Perched Aquifer ................................................. A-4
Appx. Table A-4: PA-1 Annual Perched Aquifer ........................................................... A-5
Appx. Table A-5: 89-2 Quarterly A-Groove Aquifer ...................................................... A-6
Appx. Table A-6: 90-4 Quarterly A-Groove Aquifer ...................................................... A-7
Appx. Table A-7: AG-1 Quarterly A-Groove Aquifer ..................................................... A-8
Appx. Table A-8: AG-2 Annual A-Groove Aquifer......................................................... A-9
Appx. Table A-9: MMC-IRI-4 Annual A-Groove Aquifer ............................................. A-10
Appx. Table A-10: O-GMW-A Annual A-Groove Aquifer ............................................ A-11