2023-04-07_REVISION - M2001046

• Permit No: M2001046
• IBM Index Class Name: Revision
• Doc Date: 4/7/2023
• Doc Name: Adequacy Review Response
• From: Brannon Sand & Gravel
• To: DRMS
• Type & Sequence: TR2
• Email Name: ECS
• Email Name: MAC
• Media Type: D
• Archive: No

CIVIL RES"JURCES, LLC
ENGINEERS & PLANNERS
March 31, 2023
Ready Mixed Concrete Company
Mr. Steve Kelton
2500 East Brannan Way
Denver, CO 80229
RE: Technical Revision 2 Adequacy Review-Nix Mine(Permit M-2001-046),Weld County,Colorado
Dear Mr. Kelton:
This letter is being generated to discuss the history of the Amendment 1 permitting process as it relates to groundwater
quality testing and responds to the comments from the Division of Reclamation Mining and Safety in their March 10,
2023 Technical Revision 2 Adequacy Review 1 letter.
Background
The property associated with the Division mining permit M-2001-046 (commonly "Nix Mine") was originally permitted to
Owens Brothers Concrete Company on May 30, 2003. The Nix Mine was subsequently sold to the Ready Mixed
Concrete Company, LLC and the "Transfer of Permit and Succession of Operator" application was submitted to the
Division on October 14, 2004 and approved by the Division on November 4, 2004.
RMCC applied for an Amendment to the Reclamation Permit ("Amendment 1") in 2021 to add 149.6 acres of affected
area within the 307.2 acre permit boundary and modify the post mining plan to lined water storage. Amendment 1 was
approved June 28, 2021.
As part of the Adequacy Review process of the Amendment 1 application, the Division commented that the site should,
"submit a monitoring plan to detail where and how water levels and chemistry will be monitored to document that impacts
to the prevailing hydrologic balance will be minimized and mitigated if necessary." In response to this comment, Civil
Resources, LLC ("CR") drafted a letter with the following response, "See attached monitoring plan and updated Exhibit
G. Water levels for wells 1-8 have been collected monthly by RMCC since August 2019. Water levels will continue to be
collected monthly for the life of the mine. Water levels on wells 9 through 12 were drilled in the later part of 2019 and
water levels have been collected since January 2020." Included with the response letter was a Groundwater Monitoring
and Mitigation Plan that pertained to groundwater elevation monitoring.Water quality sampling was not included with the
response to Adequacy Review 1.
On June 9, 2021, RMCC received comment in Adequacy Review 2 requesting a, "...Sampling and Analysis plan
describing how the operator will document ambient groundwater conditions relative to Tables 1-4 of the Interim Narrative
Standard prior to mining, as well as insure/document that the water quality will meet the Interim Narrative Standards
during operation and prior to release." The following response to this comment was sent in the June 4, 2021 letter to the
Division: "To document ambient groundwater conditions prior to mining, RMCC collected samples from Nix-Owens MON
4, Nix-Owens MON 5, Nix-RMCC MON 6, Nix-RMCC MON 7, and Nix-RMCC MON 8 on June 3, 2021.These wells were
selected to provide background water quality data along each roadway and the Varra pit.The analytes listed on Tables
14 of the Interim Narrative Standards,excluding the radiological section,were tested for in each of the wells sampled.
The lab results from this analysis will be included with the next annual report for the site.A list of analytes tested is
included (see attached Analytes For Baseline Sampling)."
Following a phone call with an RMCC representative and the Division, RMCC requested that CR add a Groundwater
Quality Monitoring Plan section to specifically include what analytes will be sampled for,commit to water quality sampling
8308 COLORADO BLVD SUITE 200 9 FIRESTONE CO 80504•PHONE: [phone]• FAX: [phone]