Decommissioning Projects - Quivira Mining Ambrosia Lake uranium mill site, McKinley County, New Mexico, USA 
(last updated 16 Dec 2021)
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NRC Docket No. 
(QUIVIRA MINING CO, GRANTS, NM)
NRC Source Material License No. SUA-1473
NRC Facility Info
Aerial View (tailings): Google Maps · MSRMaps 
Aerial View (mill): MSRMaps
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Geotechnical Characterization issued for Disposal Cell 4 Candidate Locations for disposal of contaminated soils at former Ambrosia Lake uranium mill site:
Byproduct material-affected (BMA) soils at the site have been identified as an existing reclamation item and include windblown tailings, pond-affected soils, and contact soils beneath, and adjacent to, former process plant areas. Thus, RAML [Rio Algom Mining LLC] has asked Stantec for assistance selecting an on-site repository location (Cell 4) to contain approximately 500,000 cubic yards (cy) [382,000 m3] of the BMA soils.
> Download: Rio Algom Cover Letter to NRC , May 26, 2022 (214kB PDF)
> Download: Work Plan for The Rio Algom Mining Ambrosia Lake Mill Site: Geotechnical Characterization for Disposal Cell 4 Candidate Locations , February 7, 2022 (37.1MB PDF)
Stormwater breaches berm at former Ambrosia Lake uranium mill site
The Ambrosia Lake Valley experienced a series of extreme precipitation events from July 21st
through 28th, 2021. [...]
The severe storms caused run-on to RAML [Rio Algom Mining LLC] property predominantly from property owned and controlled by others (involving several sections of land). This extreme precipitation resulted in excessive impounding of run-on water in the former Section 4 Ponds area; this impounded water ultimately breached an earthen containment berm that RAML uses to create a "non-discharging" watershed. The location of the berm breach is shown in the attached figure. Stormwater passed through the breached berm and ultimately flowed through non-industrial areas of RAML property and into the Arroyo del Puerto in an area downstream of existing the Ambrosia Lake West Mill outfalls.
(Rio Algom letter to NRC , Nov. 22, 2021)
NRC announces opportunity to request a hearing and to petition for leave to intervene concerning proposed burial of contaminated waste materials at former Ambrosia Lake uranium mill site
The U.S. Nuclear Regulatory Commission (NRC) has received an application from Rio Algom, LLC, Ambrosia Lake facility for amendment of Materials License SUA-1473, which authorizes the burial of contaminated waste materials resulting from previous onsite milling operations into designated onsite disposal areas. The amendment would allow the release of the Section 4, Ponds at the Ambrosia Lake facility for unconditional use and update the license accordingly.
A request for a hearing or petition for leave to intervene must be filed by May 7, 2018.
> Federal Register Volume 83, Number 46 (Thursday, March 8, 2018) p. 9874-9876 (download full text )
> Access Docket ID NRC-2018-0042
On Oct. 20, 2020, Rio Algom Mining LLC retracted this license amendment request.
Residual contamination exceeds limits at Section 4 Ponds area of former Ambrosia Lake Mill Facility, New Mexico
"This confirmatory survey determined that of the 41 confirmatory units investigated, more than half (22) contained areas of residual contamination that exceed the established limits. Based on the systematic confirmatory investigation of a sample population and the spatial distributions of confirmatory samples where individual or collective radionuclide concentrations exceeded cleanup criteria, there is a high probability that numerous other as-yet unidentified locations in excess of the cleanup limits exist over all portions of the Section 4 Ponds area. A potential root cause as to why the licensee did not identify the residual contamination may be a result of the reliance upon the Ra-226 gamma radiation to cleanup limit correlation, when Th-230 is the now the primary ROC. ORAU's independent conclusion is that the Section 4 Ponds area does not meet the decommissioning plan requirements for release from radiological controls."
> Download Re-Confirmation Survey of the Section 4 Ponds Area at the Rio Algom
Ambrosia Lake Facility, Ambrosia Lake, New Mexico , by Timothy J. Vitkus, Oak Ridge Associated Universities, November 2015 (5.2MB PDF)
NRC authorizes alternate on-site disposal cell location for disposal of byproduct material at Ambrosia Lake Mill Facility, New Mexico
The Nuclear Regulatory Commission (NRC) is considering the issuance
of a license amendment to Source Materials License SUA-1473 issued to
Rio Algom Mining LLC (Rio Algom, or the Licensee) to authorize an
alternate on-site disposal cell location for disposal of byproduct
material at its Ambrosia Lake Mill Facility, in Ambrosia Lake, New
Mexico.
The current licensing action is to provide an alternate on-site
disposal area for placing byproduct material such as mill building
debris and windblown impacted soil.
The NRC has prepared an Environmental Assessment (EA) for this
proposed action in accordance with the requirements of 10 CFR part 51.
Based on the EA, the NRC has concluded that a Finding of No Significant
Impact (FONSI) is appropriate with respect to the proposed action. The
amendment will be issued following the publication of this Notice.
Federal Register: October 15, 2010 (Volume 75, Number 199) p. 63518-63519 (download full text )
> Download Environmental Assessment, Oct. 2010 (153k PDF)
On Nov. 3, 2010, NRC issued the requested license amendment.
NRC issues Environmental Assessment and Finding of No Significant Impact for
site protection measures from surface water flow at Ambrosia Lake uranium mill tailings site
Federal Register: August 8, 2008 (Volume 73, Number 154) p. 46337-46339 (download full text )
NRC approves Cell 2 Expansion Reclamation Plan at Ambrosia Lake uranium mill tailings site
Notice of Availability of Environmental Assessment and Finding of
No Significant Impact for Cell 2 Expansion Reclamation Plan License
Amendment; Rio Algom Mining LLC, Ambrosia Lake, NM
Federal Register: November 13, 2007 (Volume 72, Number 218) p. 63934-63935 (download full text )
Environmental Assessment for the Tailings Cell 2 Expansion Reclamation Plan, Rio Algom Mining LLC's Uranium Mill Facility, Ambrosia Lake, New Mexico, Final Report, September, 2007 (ADAMS Acc. No. ML072670278)
License Amendment SUA-1473, Amendment 58, Dec. 10, 2007 (ADAMS Acc. No. ML073050340)
NRC issues final Environmental Assessment finding No Significant Impact for Soil Decommissioning Plan at Ambrosia Lake uranium mill tailings site
Environmental Assessment for the Soil Decommissioning Plan Rio Algom Mining LLC's uranium mill facility, Ambrosia Lake, New Mexico, Final Report, May 15, 2006 (ADAMS ML061630291)
Federal Register: July 3, 2006 (Volume 71, Number 127) p. 37962-37964
(download full text )
The requested license amendment was issued on Aug. 16, 2006.
Rio Algom issues Soil Decommissioning Plan for Ambrosia Lake uranium mill tailings site
> Download Soil Decommissioning Plan, Rio Algom Mining LLC Ambrosia Lake Facility, Grants, New Mexico, May 1, 2006, 189 p. (10.7MB PDF - ADAMS ML061320449)
"The purpose of the Plan is to remediate the windblown tailings, effluent contaminated soils, and soils contaminated by license activities that originated from the milling operation and disposal area, and to demonstrate that the clean-up plan was successful in remediating the contaminated soils to comply with the proposed release criteria. For areas of deeper contamination attributed to licensed activities, RAM will apply Alternate Release Criteria (ARC) to allow these soils to be left in place with an appropriate cover. The ARC will achieve appropriate closure to allow for the transfer of these areas to the U.S. Department of Energy under institutional controls."
NRC issues Draft Environmental Assessment on Soil Decommissioning Plan for Ambrosia Lake uranium mill tailings site
Draft Environmental Assessment Soil Decommissioning Plan for Rio Algom Mining LLC's Uranium Mill Facility, Ambrosia Lake, New Mexico, Feb. 28, 2006
NRC issues Environmental Assessment finding No Significant Impact for Lined Evaporation Ponds Relocation Plan at Ambrosia Lake uranium mill tailings site
On June 17, 2005, NRC issued an Environmental Assessment finding No Significant Impact for Lined Evaporation Ponds Relocation Plan at Ambrosia Lake uranium mill tailings site.
Federal Register: June 24, 2005 (Volume 70, Number 121) p. 36663-36664 (download full text )
> Access Environmental Assessment via ADAMS (Acc. no. ML051680226)
NRC accepts use of marginal quality rock for Ambrosia Lake uranium mill tailings cover
By letter to Rio Algom dated March 9, 2004, the U.S. NRC accepted the use of rock of marginal quality for the cover of the Ambrosia Lake uranium mill tailings: "The results of the testing and subsequent analysis show that the rock does not meet a minimal score of 80. However, Rio Algom followed the procedure in NUREG-1623 that allows for rock of marginal quality (scores less than 80) to be oversized to meet the requirements of 10 CFR Part 40."
NRC issues Environmental Assessment and Finding of No Significant Impact on Ambrosia Lake uranium mill demolition
Federal Register: October 15, 2003 (Volume 68, Number 199) p. 59420-59421 (download full notice )
NRC changes Ambrosia Lake license from standby to possession-only
On August 1, 2003, the Nuclear Regulatory Commission (NRC) changed the license for the Ambrosia Lake facility in status from standby to possession-only.
NRC announces opportunity to request hearing on Ambrosia Lake mill demolition plan
Notice in Federal Register, Jan 24, 2003 (Vol. 68, No. 16), p. 3570-3571 (download full notice ):
" The Nuclear Regulatory Commission (NRC) has received, by letter
dated December 10, 2002, a proposed mill demolition plan for the
removal of the mill located at Rio Algom Mining Limited Liability
Corporation's uranium mill facility at Ambrosia Lake, New Mexico. In
accordance with License Condition 29 of NRC Source Materials
License, SUA-1473, the mill demolition plan describes the demolition of
the structural features associated with the Ambrosia Lake uranium mill
facility. The plan addresses the removal of surface structures in
preparation for subsequent implementation of the surface reclamation
release phase of the overall site decommission process."
Note: The ADAMS Accession Number ML030070154 given in the notice for the application for the license amendment and proposed decommissioning and reclamation plan is incorrect.
NRC grants further 3-year delay of decommissioning of Ambrosia Lake mill site
On April 5, 2002, NRC granted Rio Algom's request for a further 3-year delay to the initiation of the decommissioning process at the Ambrosia Lake mill.
By letter dated March 1, 2002, Rio Algom's subsidiary Quivira Mining had requested a further 3-year delay to the initiation of the decommissioning process at the Ambrosia Lake facility. "This allows Rio Algom to maintain the mill for future operations while market conditions are improving." In 1997, Rio Algom had been granted a first 5-year delay.
NRC grants 2-year extension of reclamation deadline for Ambrosia Lake tailings
On January 3, 2002, NRC granted the requested 2-year extension of the deadline for completion of the erosion protection for impoundment #2.
By letter dated November 6, 2001, Rio Algom Mining Corp. is requesting a two year extension to the deadline for the completion of reclamation work on Impoundment #2.
Rio Algom claims that the construction material, primarily the rock specified in the proposed erosion protection design, currently under NRC review, is not available from a local source, at a reasonable cost, within the time remaining before the deadline.
NRC approves requested groundwater alternate concentration limits at Ambrosia Lake uranium mill tailings site
On Feb. 24, 2006, NRC issued the requested license amendment.
> Download Technical Evaluation Report, Alternate Concentration Limits Application, Rio Algom Mining, LLC, Ambrosia Lake uranium mill facility, New Mexico, Feb. 24, 2006 (ADAMS)
> Download Environmental Assessment for amendment to Source Materials License SUA-1473 for ground water alternate concentration limits, Rio Algom Mining LLC, Ambrosia Lake uranium mill tailings site, Ambrosia Lake, McKinley County, New Mexico, January 2006 (ADAMS)
On June 11, 2001, Quivira Mining requested alternate concentration limits for a number of constituents in the alluvium (shallow) groundwater at its Ambrosia Lake uranium mill tailings site. This request follows a similar one concerning deeper aquifers (see below).
Ambrosia Lake alluvium groundwater standards
| | GPS | ACL |
| Molybdenum [mg/L] | 0.06 | 83 |
| Nickel [mg/L] | 0.06 | 0.14 |
| Selenium [mg/L] | 0.05 | 3.1 |
| Natural Uranium [mg/L] | 0.06 | 11.1 |
| Gross Alpha * [pCi/L] | 15 | 16726 |
| Thorium-230 [pCi/L] | 3.1 | 10 |
| Radium-226 + Radium-228 [pCi/L] | 5.0 | 196.1 |
| Lead-210 [pCi/L] | 4.9 | 58 |
* excluding radon and uranium
GPS = current site-specific NRC Groundwater Protection Standards
ACL = Alternate Concentration Limits proposed by Quivira Mining
1 pCi/l = 37 mBq/l
Background documents are available through ADAMS .
NRC revokes approval for release of a reclaimed evaporation pond at Ambrosia Lake mill site for unrestricted use
Based on elevated radium concentrations found in soil samples taken in November 1999, NRC on June 5, 2000 revoked its 1988 approval for the release of evaporation pond No. 8 for unrestricted use.
NRC issues Environmental Assessment and Finding of No Significant Impact on Rio Algom/Quivira Mining request for relaxed groundwater standards at Ambrosia Lake mill site
Federal Register: January 27, 2006 (Volume 71, Number 18) p. 4622-4624 (download full text )
> Download Environmental Assessment for Amendment of Source Materials License SUA-1473 for Ground Water Alternate Concentration Limits, Rio Algom Mining, LLC, Ambrosia Lake, New Mexico, Jan. 20, 2006 (ADAMS)
Notice in Federal Register, June 29, 2000 (Vol. 65, No. 126), p.40144 (download full notice ):
"SUMMARY: Notice is hereby given that the U.S. Nuclear Regulatory
Commission (NRC) has received, by letter dated February 17, 2000, an
application from Quivira Mining Company (Quivira) to establish
Alternate Concentration Limits and amend the Source Material License
No. SUA-1473 for the Ambrosia Lake uranium mill facility."
A request for hearing must be filed within 30 days from June 29, 2000.
The Quivira Ambrosia Lake tailings pile with its contents of 30.1 million metric tonnes is the largest uranium mill tailings pile in the U.S.
Quivira requests alternate concentrations limits for uranium up to 40-fold the current site standard (GPS), for thorium-230 up to 378-fold the GPS, for radium-226 and 228 up to 8-fold the GPS, among others:
Ambrosia Lake groundwater standards
| Constituent | | Bedrock unit |
Dakota
Sandstone | Tres Hermanos
A Sandstone | Tres Hermanos
B Sandstone |
| U-nat [mg/l] | GPS | 0.02 | 0.01 | 0.02 |
| ACL | 0.81 | None | 0.25 |
| Th-230 [pCi/l] | GPS | 2.3 | 4.3 | 2.2 |
| ACL | 869 | 139 | 139 |
| Ra-226 and -228 [pCi/l] | GPS | 5.0 | 5.0 | 7.4 |
| ACL | 41 | 41 | 41 |
| Pb-210 [pCi/l] | GPS | 1.9 | 4.1 | 0.9 |
| ACL | 57 | 13 | 13 |
| Nickel [mg/l] | GPS | 0.03 | 0.05 | 0.06 |
| ACL | 0.1 | None | 0.37 |
GPS = current Groundwater Protection Standard, ACL = proposed Alternate Concentration Limit
1 pCi/l = 37 mBq/l
Background documents are available through ADAMS .
> View background information on Uranium Mill Tailings Management - USA