DRC-2024-004919

Rio Algom Mining LLC
March 7, 2024
Mr. Adam Wingate
Utah Department of Environmental Quality
Division of Waste Management and Radiation Control
195 North 1950 West
Salt Lake City, UT 84114-4880
Div of Waste Management
and Rad:ation Control
MAR 15 2024
RE: Corrective Action Assessment Work Plan Phase 1 Completion Notice
Rio Algom Mining LLC Lisbon Facility, San Juan County, Utah
Radioactive Material License Number UT1900481
Dear Mr. Wingate:
Rio Algom Mining LLC (RAML) submitted the Corrective Action Assessment Work Plan (CAAWP)
(INTERA, 2022) for the Lisbon Facility in San Juan County, Utah, on November 16, 2022. RAML
is now executing the CAAWP in accordance with Stipulated Compliance Order DRC-2023-
077694.
RAML initially planned to complete the CAAWP geologic coring data collection and monitoring
well installation program in two planned phases:
• Phase 1 Drilling Program consisting of geologic coring as 12 locations and monitoring well
installations at 19 locations within the RAML restricted area and/or on private lands which
RAML owns or for which RAML has secured access agreements.
• Phase 2 Drilling Program consisting of the geologic coring data collection and monitoring
well installation at remaining locations , which are on public lands administered by the
Bureau of Land Management (BLM).
This letter notifies DWMRC that RAML has concluded the Phase 1 CAAWP Drilling Program,
which occurred from September 18, 2023 to February 7, 2024. Through adaptive implementation,
as described in the Section 1.1 of the CAAWP and a CAAWP implementation update letter (RAML,
2023), RAML made the following changes to the above planned scope:
1. Added corehole PC-142 adjacent to monitoring well location PW-142 to provide additional
geologic data for inclusion into the hydrogeologic conceptual site model, and
2. Not installed monitoring well PW-164S adjacent to well PW-164D because a separate
shallow groundwater system was not encountered during drilling . Monitoring well
PW-164D is representative of the saturated Burro Canyon sandstone at the 164 location.
P.O.Box218,Grants,NMUSA 87020 -Tel: [phone]
CAAWP Phase 1 Completion Notice
March 7, 2024 Page 2
The final set of 11 coreholes and 15 monitoring wells completed during the Phase 1 CAAWP
Drilling Program are listed in attached Table 1.
Because of unusually warm wet weather leading to muddy and unsafe site conditions, RAML was
unable to complete two coreholes and four monitoring wells that were a part of planned Phase 1
activities:
• LPC-6 (Corehole)
• LPC-8 (Corehole)
• PW-142 (Monitoring Well)
• LPW-6 (Monitoring Well)
• LPW-7 (Monitoring Well)
• LPW-8 (Monitoring Well)
The above coreholes and monitor wells will instead be completed as part of the Phase 2 CAAWP
Drilling Program. Five of the above locations are on the Lower Tailing lmpoundment, where driving
equipment in muddy conditions could compromise the cover surface . While coreholes LPC-7 and
PC-142 were completed during Phase 1, RAML was unable to install the associated monitoring
wells as planned due to the wet, muddy site conditions. Instead, RAML abandoned the coreholes
at LPC-7 and PC-142 in accordance with Utah Administrative Code Section R655-4 (Utah Division
of Water Rights, 2022). Monitoring wells LPW-7 and PW-142 will be installed in new borings
located adjacent to coreholes LPC-7 and PC-142 during the Phase 2 CAAWP Drilling Program.
RAML is taking steps to expeditiously complete the CAAWP field program in a manner that meets
the CAAWP's objectives in a safe and environmentally protective manner. Currently, the Phase 2
Drilling Program is planned to begin in Summer 2024 following RAML receipt of access approval
from the BLM. RAML will keep DWMRC staff informed of schedule developments . After
completion of Phase 2 field activities and data collection, RAML will provide complete
documentation of the CAAWP activities in a Field Investigation Report as described in the
CAAWP.
If you have any questions or need additional information, please do not hesitate to contact me at
[phone].
Sincerely,
Rio Algom Mining LLC
Jt:~
Principal Hydrogeologist USA Legacy Assets
cc: Stephen Pitton , LM DOE (electronic only)
Kevin Ramsay, Operations Manager, BHP Legacy Assets USA
P.O . Box 218 , Grants, NM USA 87020 -Tel: [phone]
CMWP Phase 1 Completion Notice
March 7, 2024
References
Page 3
INTERA Incorporated (INTERA). 2022. Corrective Action Assessment Work Plan, Lisbon Facility,
Rio Algom Mining LLC, Radioactive Material License Number UT 1900481, San Juan County,
Utah. November 16.
Rio Algom Mining LLC (RAML). 2023. Letter Phil Goble, DWMRC, regarding Corrective Action
Assessment Work Plan Adaptive Implementation Update, September 2023. September 26.
Attachments
Table 1 Phase 1 CMWP Drilling Program Completed Coreholes and Monitoring Wells
P.O.Box218,Grants,NMUSA 87020 -Tel: [phone]
'
Table 1
Phase 1 CAAWP Drilling Program Completed Coreholes and Monitoring Wells
Rio Algom Mining LLC Lisbon Facility, San Juan County, Utah
Radioactive Material License Number UT1900481
Lisbon Phase 1 Field Program Status Tracker ----------------------------------------
Downhole Geophysics Well Construction
Well ID/Corehole ID Location Drilled? Completed? Completed?
UPC-1 Yes Yes NA
UPW-1 Yes NA Yes
UPC-2 Yes Yes NA
UPW-2 Yes NA Yes
UPC-3 Yes Yes NA
UPW-3 Yes NA Yes
UPC-4 Yes Yes NA
UPW-4 Yes NA Yes
UPC-5 Yes Yes NA
UPW-5 Yes NA Yes
LPC-6 No No NA
LPW-6 No NA No
LPC-7 Yes Yes NA
LPW-7 No NA No
LPC-8 No No NA
LPW-8 No NA No
PC-140 Yes Yes NA
PW-140 Yes NA Yes
PC-141 Yes Yes NA
PW-141 Yes NA Yes
PC-142 Yes Yes NA
PW-142 No NA No
PC-147 Yes Yes Yes
PW-147 Yes NA Yes
PW-148 Yes Yes Yes
PW-133D Yes Yes Yes
PW-161 Yes Yes Yes
PC-164 Yes Yes NA
PW-164S No No No
PW-164S* NA NA NA
PW-164D Yes Yes Yes
PW-165 Yes Yes Yes
PW-166 Yes Yes Yes
Notes:
Scope that was not completed in Phase 1 will be completed in Phase 2.
* -Monitoring well PW-164S was not installed adjacent to monitoring well PW-164D because a separate shallow
groundwater system was not present.
NA -Not applicable; coreholes were not designated for well installation and downhole geophysics were not designated
for well boreholes.