DRC-2024-006135

July3, 2024
Liz Ruedig, Site Manager
Rio Algom Mining LLC
P.O. Box 218
Grants, NM 87020
Subject:2023Annual Groundwater Monitoring Report and 2023 Split Sampling InspectionRadioactive Material License Number 1900481
Dear Ms. Ruedig:
The Utah Division of Waste Management and Radiation Control (Division) has reviewed the Rio Algom Mining, LLC (RAML) February 28, 2024, 2023Annual Ground Water Monitoring Report for
the Lisbon Facility (2023 Report) (DRC-2024-004739); and theDivision/RAMLLisbon Facility split sampling event inspection, which occurred on October 25, 2023.
The 2023Report was reviewed to determine compliance with the RAML Lisbon Facility Radioactive Materials License No. UT1900481, Amendment 7 (License), Condition 29.
The Divisionreview considered ongoing actions and documents related to groundwater compliance at the facility including:
Out of Compliance (“OOC”) status for uranium in groundwater monitoring wells RL-1, RL-3 and EF-8, and arsenic in monitoring well OW-UT-9, and RAML implementation of accelerated groundwater
monitoring at those wells.
The RAMLHydrogeological Supplemental Site Assessments for the Lisbon Facility, the Corrective Action Assessment Work Plan, and the site’s progression towards a Groundwater Corrective
Action Plan.
The approved RAML July 31, 2015 “Groundwater Monitoring Plan Version 2.0” (“GWMP”).
Based on Division review, and with consideration of ongoing actions to address out-of-compliance issues at monitoring wells OW-UT-9, RL-1, RL-3 and EF-8, it appears thatthe 2023 Report
is in compliance with the reporting requirements of the License and that the collected data is reliable for compliance purposes. Therefore, the 2023 Report review is hereby closedout.
October 25, 2023,Division/RAML Split Sample EventReview:Division staff met with representatives of RAML and Arcadison October 25, 2023,to conduct groundwater split sampling at the Lisbon
Facility. The Division split groundwater samples with RAML at two monitoring wells, RL-6 andH-63.Per Division review of field sample collection methods and documentation, no issues
were identified.Comparison of the October 25, 2023, RAML/Division split samples showed that sample results for all constituents were within acceptance criteria (as specified by the DRC
Split Sample Guidance Document for Uranium Mills, dated August 7, 2007, and Division Data Review).
If you have questions concerning this letter, please contact Chris Leahy at [phone].
Sincerely,
Adam Wingate, Uranium Recovery Manager
Division of Waste Management and Radiation Control
AJW/CL/jk
cc:Grant Sunada, Health Director, San Juan Public Health DepartmentDennis Shumway, Environmental Health Director, San Juan Public Health Department
Curtis Page, P.E., UDEQ District Engineer
Sandra L. Ross, Vice President, Rio Algom Mining LLC