2022-12-21_PERMIT FILE - M2022001

• Permit No: M2022001
• IBM Index Class Name: Permit File
• Doc Date: 12/21/2022
• Doc Name Note: Response No 7
• Doc Name: Adequacy Review Response
• From: Red Tierra Equities, LLC/Civil Resources, LLC
• To: DRMS
• Email Name: PSH
• Email Name: JLE
• Media Type: D
• Archive: No

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ENGINEERS 6 PLANNERS
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December 2001, 2022 �V �1ti P�\Oo'
Mr. Peter Hays pFQ`O
Division of Reclamation, Mining,and Safety
1313 Sherman Street,Room 215 O\��
Denver, Colorado 80203 �00
RE: Red Tierra Equities, L.L.C.,Section 20 Mine, File No. M-2022.001, 112c Permit Application
Adequacy Review 7 Response
Dear Mr. Hays:
This letter addresses the Adequacy Review letter dated December 18th,2022 regarding the Section 20
Gravel Mine 112 Construction Materials Reclamation Permit Application Package. Responses to your
comments follow in bold:
Groundwater Model
1. In response to Item#3, the Applicant stated the Groundwater Model Report has been updated
to directly address the infiltration pond model run. The recommendations from the
groundwater model have not changed. Red Tierra has committed to installing the infiltration
pond by including it in the exhibits and it will be included in the bonding calculation.
The Division considers the Gilcrest Area Alluvial Groundwater Model report to be the
demonstration and justification for the proposed groundwater mitigation plan. Therefore, the
mitigation measures described in the report must correspond to the proposed mitigation
measures described in permit application exhibits. Please revise the groundwater model
report to incorporate the currently proposed mitigation plan to use underdrains and/or
extraction wells to transfer mounded groundwater along the southern boundary of the site to
an infiltration pond located north of Cell 7. The revised report shall include updates to the
Mitigation, Phase 2 Mitigation, Mitigation with Recharge and Conclusion sections of the report,
at minimum.
Please note, the Applicant is not required to resubmit the appendixes to the report unless the
revised report updates the information contained in the appendixes.
The report has been revised to show two mitigation scenarios,one where water is removed from the
model simulating surface flow to the river and one where flow is directed to the infiltration pond.
The surface flow removal scenario was kept in the report in case Red Tierra wishes to apply for an
amendment and add the underdrain discharge line at a later date. The infiltration pond scenario is
recommended in the latest revision and Figures 11 and 12 have been added to show the head
contours for the two phases described for the infiltration pond mitigation scenario.
2. In response to Item#4, the Applicant stated Exhibit G- Water Information has been updated
to "... or if the miner or the Division receives a complaint from any well owner within 600 feet
of the site boundary, then the miner will evaluate the cause and take action within 7 days and
notify the ORMS." Exhibit G has been included in the appendices of the Groundwater Model
Report and language has been added in the conclusions stating that the operator will comply
with the Groundwater Level Monitoring and Mitigation plan. Please commit to investigating all groundwater
impact complaints, not just complaints from
well owners within 600 feet of the site boundary, received by the Operator or the Division.
Please update the groundwater model report and Exhibit G-Water Information accordingly.
Please note, the burden to demonstrate any groundwater impacts to the prevailing hydrologic
balance is the responsibility of the Permittee.
B308 C❑LORADO BLVD • SUITE 200 • FIRESTONE, COLORAo❑ B0504 • PHONE: [phone] • FAX:
303.833.28S❑