2023-05-02_REVISION - M2001046

• Permit No: M2001046
• IBM Index Class Name: Revision
• Doc Date: 5/2/2023
• Doc Name: Adequacy Review Response #2
• From: Brannan Sand & Gravel Co/Ready Mix
• To: DRMS
• Type & Sequence: TR2
• Email Name: ECS
• Email Name: MAC
• Media Type: D
• Archive: No

TABLE OF CONTENTS
1. BACKGROUND..................................................................................................... 3
Figure 1: Nix Mine Site and Vicinity ............................................................................. 3
2. BASELINE GROUNDWATER DATA..................................................................... 4
2.1 Baseline Groundwater Quality Data................................................................... 4
Table 1: Baseline Groundwater Quality Data................................................................ 5
Figure 2: Nix Groundwater Levels, Wells, and Adjacent Mine Sites............................. 6
2.2 Baseline Groundwater Quantity Data................................................................. 7
Figure 3: Groundwater Hydrographs............................................................................. 7
3. WATER QUALITY MONITORING ......................................................................... 8
3.1 Introduction........................................................................................................ 8
3.2 Sampling Methodology....................................................................................... 8
3.2.1 Background Monitoring and Point of Compliance (POC) Locations.................... 8
Table 2: Groundwater Monitoring Stations................................................................... 8
3.2.2 Monitoring Frequency.......................................................................................10
3.2.3 Monitoring Parameters......................................................................................10
Table 3: Baseline and Operational Water Quality Parameters....................................11
Table 4: Omitted Parameters from CDPHE Regulation 41, Tables 1-4.......................11
3.2.4 Sampling Protocol.............................................................................................12
3.3 Analytical Procedures: Comparison to State Water Quality Standards..............13
3.4 Water Quality Mitigation Plan............................................................................14
3.5 Annual Report...................................................................................................14
4. WATER LEVEL MONITORING PLAN..................................................................15
4.1 Monthly Monitoring............................................................................................15
4.2 Criteria and Trigger Values...............................................................................15
Attachment A: Field Sheets and Instrument Calibration Sheet.......................................17
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