Decommissioning Projects - United Nuclear Church Rock uranium mines and mill, McKinley County, New Mexico, USA
(last updated 15 Feb 2019)
> See also Issues for:
New Mining Projects ·
Operating Mines ·
Legislation & Regulations
> See also Data for:
Deposits, Proposed and Active Mines ·
Old Mines and Decommissioning
NRC Docket No. 40-8907 (UNC MINING & MILLING (DIV. OF UNITED NUCLEAR CORP.), Church Rock, NM)
NRC Material License No. SUA-1475
NRC Facility Info
Aerial view: Google Maps · MSRMaps
> View EPA Region 6 Superfund Site Progress Profile
> Download EPA Region 6 UNC Church Rock factsheet
> Download EPA Region 6 UNC Church Rock Five-Year Review Report (Sep. 2003): without maps and photographs (3.8MB PDF) · (full report available through NRC ADAMS )
Modeling effort fails to analyze water balance of soil covers at selected uranium mill tailings sites
> View here
United Nuclear requests five-year extension to groundwater corrective actions at Church Rock mill and tailings site
By letter dated Sep. 18, 2013, United Nuclear Corp. requested a five-year extension for the projected completion of groundwater corrective actions and subsequent dates for placement of the final radon barrier and erosion protection.
NRC approved the requested five-year extension for the projected completion of groundwater corrective actions on Nov. 7, 2013.
NRC invites comment on requested extension of date for emplacing final radon barrier and erosion protection at former Church Rock uranium mill site:
However, prior to making a final determination on the UNC's second request to extend the date for emplacing the final radon barrier and the erosion protection, the NRC is providing an opportunity for public participation. Specific comments are requested on the extension of the date for emplacement of the final radon barrier and the erosion protection from December 31, 2014 to December 31, 2019.
Comments should be provided within 30 days of April 30, 2014.
> Federal Register Volume 79, Number 83 (Wednesday, April 30, 2014) p. 24459-24460 (download full text )
> Access Docket ID NRC-2014-0096
On April 17, 2012, United Nuclear Corp. sent to NRC a License Amendment Request for Revised Background Standards Based on Updated Background Concentrations.
> Download License Amendment Request April 17, 2012 (PDF)
NRC offers opportunity to request a hearing and to petition for leave to intervene on United Nuclear's requests for relaxed groundwater protection standards at the Church Rock uranium mill and tailings site:
A request for a hearing or petition for leave to intervene must be filed by April 23, 2013.
> Federal Register Volume 78, Number 36 (Friday, February 22, 2013) p. 12365-12368 (download full text )
Note: The ADAMS Package Accession No. given in the FR notice for the license amendment request is incorrect!
> Access Docket ID NRC-2013-0036
NRC approves United Nuclear's requests for relaxed groundwater protection standards at the Church Rock uranium mill and tailings site:
On April 9, 2015, the NRC issued License Amendment No. 52 approving United Nuclear's requests for relaxed groundwater protection standards at the Church Rock uranium mill and tailings site.
> Federal Register Volume 80, Number 78 (Thursday, April 23, 2015) p. 22744-22746 (download full text )
> Download License Amendment No. 52 , April 9, 2015
> Download Technical Evaluation Report , April 2015
> Download Final Environmental Assessment , April 2015
NRC invites comments on scoping for EIS on proposal to place mine waste repository on top of reclaimed Church Rock uranium mill tailings deposit:
The U.S. Nuclear Regulatory Commission (NRC) received a
license application by letter dated September 24, 2018, from United
Nuclear Corporation (UNC). By this application, UNC is requesting
authorization to amend its license (SUA-1475) to excavate approximately
1 million cubic yards (CY) of mine spoil from the Northeast Church Rock
Mine Site and dispose of it at the existing mill site in Church Rock,
New Mexico (the proposed action). The NRC staff will prepare an EIS to
document the potential environmental impacts from the proposed action
and reasonable alternatives. As part of the EIS development process,
the NRC is seeking comments on the scope of its environmental review.
Comments must be filed by April 19, 2019.
> Download: NRC release Feb. 14, 2019 (PDF)
> Federal Register Volume 84, Number 27 (Friday, February 8, 2019) p. 2935-2937 (download full text )
> Access Docket ID NRC-2019-0026
United Nuclear requests licence amendment to place mine waste repository on top of reclaimed Church Rock uranium mill tailings deposit
"[...] Proposed activities at the site include construction of a Repository for mine-impacted soil and debris on the licensed mill tailings disposal area. Mine waste will be removed from the Northeast Church Rock Mine Site (based on defined cleanup standards), transported to and placed in the Repository, located on the existing tailings disposal area. The Repository design includes specific procedures for protection of the existing radon barrier over the mill tailings and an erosion-resistant, evapotranspirative (ET) cover over the mine waste. Stormwater controls will be added in the immediate vicinity of the Repository and to the Pipeline Arroyo. [...]
The Repository layout includes a design capacity of 1,033,500 cubic yards [790,167 m3] of mine waste with the ability to accommodate variations in the mine waste volume between about 955,000 cubic yards and 1,110,000 cubic yards."
> Download: UNC Application for License Amendment, US NRC Source Material License SUA-1475 , Sep. 24, 2018
Pre-Design Studies Work Plans released for proposed disposal of contaminated soil from the North East Church Rock Mine site on top of the existing Church Rock uranium mill tailings disposal cell:
Northeast Church Rock Mine Site Removal Action, Pre-Design Studies Work Plan, Northeast Church Rock Mine Site, August 16, 2013:
> Download: Part 1 · Part 2 · Part 3 · Part 4 · Part 5 · Part 6
Northeast Church Rock Mine Site Removal Action, Pre-Design Studies Work Plan, Church Rock Mill Site, August 16, 2013:
> Download: Part 1 · Part 2 · Part 3
EPA issues Record of Decision for disposal of contaminated soil from the North East Church Rock Mine site on top of the existing Church Rock uranium mill tailings disposal cell:
> Download: Record of Decision, United Nuclear Corporation Site, McKinley County, New Mexico, Surface Soil Operable Unit , U.S. Environmental Protection Agency, Region 6, March 29, 2013 (17.9MB PDF)
EPA plans to place approximately 1.4 million short tons of contaminated soil from the North East Church Rock Mine site on top of the existing Church Rock uranium mill tailings disposal cell:
> View here
Navajo Nation President declares anniversary of Church Rock uranium tailings spill as "Uranium Legacy Remembrance and Action Day"
Navajo Nation President Ben Shelly has declared Saturday (July 16) as "Uranium Legacy Remembrance and Action Day."
The proclamation was issued to commemorate the 32nd anniversary of a uranium tailings spill near Church Rock, N.M., as well as six decades of impacts from uranium mining on the reservation.
Elected officials and other community leaders planned to gather in the Church Rock area Saturday morning for a prayer and a march to the site of the July 16, 1979 spill.
That day, millions of gallons of acidic water poured into the north fork of the Rio Puerco after an earthen uranium tailings dam failed. Within days, contaminated tailings liquid was found 50 miles downstream in Arizona.
(The Republic July 16, 2011)
Revised Site-Wide Supplemental Feasibility Study released for Church Rock mill and tailings site
> Download: Revised Site-Wide Supplemental Feasibility Study (SWSFS) for the Church Rock mill and tailings site, April 2011:
Part 1 · Part 2 (Tables) · Part 3 (Fig. 1 - 12) · Part 4 (Fig. 13 - Appendix G)
United Nuclear chasing three cows, this time...
During an environmental inspection performed on Oct. 27, 2009, United Nuclear's maintenance worker had to chase 3 cows out of the fenceline area of its reclaimed Church Rock tailings; the damage of the fenceline was repaired.
(Semi-Annual Effluent and Environmental Monitoring Report, Second Half of 2009 (July thru December), Feb. 24, 2010)
Failed groundwater cleanup at Church Rock is nothing but administrative problem, UNC says
In the Executive Summary (dated Jan. 28, 2010) of the 2009 Groundwater Corrective Action Annual Review Report for UNC's Church Rock uranium mill tailings site, UNC contractor Chester Engineers maintains that
"UNC believes that the main requirements for achieving closure of corrective action are largely administrative in nature for the Southwest Alluvium and Zone 1."
According to UNC, compliance can easily be achieved, if EPA and NRC issue the requested waivers and alternate concentration limits.
Navajo president reaffirms tribal ban on uranium mining to mark 30th anniversary of Church Rock uranium mill tailings spill
The leader of the Navajo Nation marked the 30th anniversary of a massive uranium tailings spill by reaffirming the tribe's ban on future uranium mining.
Speaking in Navajo and English, President Joe Shirley Jr. addressed about 100 people who made a seven-mile walk Thursday (July 16) to the site of the July 16, 1979 spill and to the land of Navajo ranchers who live near another contaminated site.
What Shirley called "the largest peacetime accidental release of radioactive contaminated materials in the history of the United States" occurred when 94 million gallons of acidic water poured into the north fork of the Rio Puerco after an earthen uranium tailings dam failed.
Within days, contaminated tailings liquid was found 50 miles downstream in Arizona.
(Los Angeles Times July 16, 2009)
Failed groundwater cleanup at Church Rock: United Nuclear Corp. points at EPA
In a letter dated May 20, 2009, UNC's parent company General Electric presents its view of the "Technical Impediments to Site Closure" of its Church Rock Mill Site to the NRC: in summary, the reason for the site groundwater not complying with the remediation goals is not UNC's inability/incapability to reach them, but EPA's unwillingness to relax them.
Thank you, UNC, for this "strong statement."
United Nuclear chasing horse, again...
During an environmental inspection performed on Oct. 31, 2008, United Nuclear's inspector had to chase a horse out of the fenceline area of its reclaimed Church Rock tailings; the damage of the fenceline was repaired.
(Semi-Annual Effluent and Environmental Monitoring Report July thru December, 2008; Feb. 25, 2009)
United Nuclear requests further relaxed groundwater standards at Church Rock uranium mill and tailings site
On Dec. 15, 2008, United Nuclear Corporation (UNC) requested "an amendment to Source Materials License SUA-1475, Condition 30. B., to apply Alternate Concentration Limits (ACLs) to two point-of-compliance (POC) wells within the Zone 1 hydrostratigraphic unit."
On Apr. 27, 2009, NRC informed UNC of its intent to hold the License Amendment Request in abeyance until after the completion and submittal of the comprehensive Site Wide Supplemental Feasibility Study (SWSFS) requested by the U.S. Environmental Protection Agency (EPA). The EPA has directed UNC, to develop the SWSFS, in light of the existing remedy's ineffectiveness in improving groundwater quality.
U.S. EPA opposes United Nuclear's request to halt groundwater treatment at Church Rock uranium mill tailings site
"The U.S. Environmental Protection Agency (EPA) has concerns regarding the United Nuclear Corporation's (UNC's) August 15, 2007 License Amendment request under Source Materials License SUA-1475 (License) for the permanent discontinuance of corrective action in the Southwest Alluvium. As you know, EPA has directed UNC to perform a site-wide supplemental feasibility study (SFS) at the UNC Church Rock Superfund site (Site) to evaluate other remedial alternatives for ground water and support future EPA decision-making. [...]
Currently, the cleanup standards for TDS and sulfate are being exceeded for the Southwest Alluvium, as well as Zone 1 and Zone 3 of the Upper Gallup Sandstone Formation. The SFS is intended to develop, screen, and analyze other alternatives that shall attain (or support a waiver of) those standards. [...]
Additionally, as part of the ongoing SFS, UNC has been directed to review the cleanup criteria established by EPA in the 1988 Record of Decision and assess the
appropriateness of changing some of those criteria to reflect newly promulgated federal and state standards and health-based criteria for ensuring the continued protectiveness of the remedy. The assessment will include the new federal Maximum Concentration Limit (MCL) for uranium of 30 micrograms per liter (µg/L), promulgated under the Safe Drinking Water Act. The current uranium standard established by the NRC in the License is 300 µg/L. The uranium concentrations measured in the seepage-impacted areas of the Southwest Alluvium are currently at or below the current NRC standard of 300 µg/L. However, they would exceed the 30 µg/L MCL if selected by EPA as an ARAR for the CERCLA remedy. [...]"
(U.S. EPA letter to NRC, February 12, 2008, emphasis added)
Flood event downs fence at Church Rock uranium mill tailings site
A major flood event had occured on Aug. 6, 2007, which damaged or downed the perimeter fenceline on UNC's Sec. 36 and Sec. 2 property areas on 200 and 700 feet, respectively.
(Environmental Inspection Aug. 31, 2007; in: United Nuclear Corporation: Second Half - July thru December, 2007, Semi - Annual Effluent and Environmental Monitoring Report, Feb. 26, 2008)
Flood event downs fence at Church Rock uranium mill tailings site; UNC chasing cattle...
Major flood events had occured on July 10 and 11, 2006, which damaged or downed the perimeter fencing on UNC's Sec. 36 and Sec. 2 property areas on 100 and 420 feet, respectively.
Daily surveillance was done to keep out livestock and 8 heads of cattle was chased on July 21, 2006.
(Environmental Inspection July 31, 2006; in: United Nuclear Corporation: Semi-Annual Effluent and Environmental Monitoring Report from July to December, 2006, Feb. 26, 2007)
Pilot study to improve groundwater restoration at Church Rock uranium mill tailings site by injection of alkalinity unsuccessful
The pilot study was conducted between October 2006 and February 2007 to evaluate
the use of alkalinity injection wells to enhance the ongoing remediation of Zone 3.
The injection and extraction rates observed during the pilot study were not the expected rates, and the total amount of cumulative extraction was considerably lower than calculated. As a result, the estimated travel time between the injection wells and extraction wells became prohibitive with respect to pore volume extraction rates, and the pilot test was terminated.
The lower than expected K values, extremely low injection well efficiency, and
negligible yield from 4 of the 5 extraction wells may be attributed to alteration of the Zone 3 aquifer minerals by the acidic leachate that comprises the groundwater plume.
Based on information presented above, it would take 10 times longer to accomplish
remedy goals than was hypothesized. Using what might have been envisioned as an
approximate 5 year remedy enhancement could actually take 50 years or more.
(United Nuclear Corporation, In-Situ Alkalinity Stabilization Pilot Study Report,
UNC Church Rock Site, Gallup, New Mexico, June 2007)
U.S. EPA releases Update on Ground Water Cleanup at Church Rock uranium mill tailings site
> Download Update on Ground Water Cleanup, United Nuclear Corporation Church Rock Superfund Site, Church Rock, McKinley County, New Mexico, May 2006 (1.1M PDF - U.S. EPA Region 6)
United Nuclear granted relaxed radium groundwater standard at Church Rock uranium mill tailings site
On Sep. 30, 2005, United Nuclear filed a License Amendment Request for Changing the Ground Water Protection Standard for Radium at its Church Rock uranium mill tailings site: "The proposed revision accounts for the fact that the current site standard lies well within the background concentration ranges for radium-226 and 228 in the Southwest Alluvium and Zone 1. The proposed revision incorporates a statistical testing procedure to objectively determine if the combined radium concentration is attributable to the occurrence and migration of seepageimpacted
water or if it is within the normal and expected background distribution."
On Feb. 22, 2006, United Nuclear submitted a revised license amendment request and technical analysis report.
On July 26, 2006, NRC staff issued a related Environmental Assessment and Finding of No Significant Impact.
> Federal Register: August 2, 2006 (Volume 71, Number 148) p. 43822-43823 (download full text )
On Aug. 9, 2006, the NRC issued the requested license amendment.
United Nuclear intends to inject alkalinity into aquifer to improve groundwater restoration at Church Rock uranium mill tailings site
Given that the currently pursued groundwater restoration scheme of removal and evaporation apparently cannot meet the remedial objectives, United Nuclear now plans to inject alkalinity into the aquifer to enhance remediation of the Zone 3 groundwater at the Church Rock uranium mill tailings site.
"This Pilot Study will evaluate the use of alkalinity injection wells to enhance the ongoing remediation of Zone 3 in addition to using extraction wells alone at the United Nuclear Corporation (UNC) Church Rock Site (site) located in Gallup, New Mexico. This Pilot Study has been prepared on behalf of UNC by Blasland, Bouck & Lee, Inc. (BBL).
The planned studies will test the injection of alkalinity-rich groundwater from an unimpacted part of the Southwest Alluvium into the Zone 3 aquifer. The injected water (hereinafter referred to as "fixiviant") will then flow through the Zone 3 formation to recovery wells where the fixiviant will be pumped to the surface for treatment and disposal. Theoretically, injection of the alluvium groundwater (i.e., fixiviant) into Zone 3 would effect the following changes:
1. The pH of the Zone 3 groundwater would increase;
2. Groundwater migration of target Zone 3 groundwater constituents of concern (such as cadmium, cobalt, nickel, radium-226/228, Th-230 and gross-alpha) would be reduced or eliminated via changes in aqueous/solid partitioning and precipitation reactions as a result of the increased pH conditions; and
3. Groundwater and fixiviant withdrawn by the extraction wells would recover uranium (and other chemical species) in solution, which could then be handled via the existing evaporation system.
The specific pilot study described herein will be conducted to assess the effectiveness of this proposed remedial approach. In addition, information obtained from the pilot study will be used to prepare a full-scale design, if groundwater remediation via injection is deemed a viable and effective remedy for the Zone 3 aquifer."
(UNC Church Rock Site In-Situ Alkalinity Stabilization Pilot Study, October 2005)
United Nuclear chasing horse, this time...
During an environmental inspection performed on Jun. 28, 2005, United Nuclear's inspector had to chase a horse out of the fenceline area of its reclaimed Church Rock tailings, though no damage of the fenceline could be observed.
(Semi-Annual Effluent and Environmental Monitoring Report from January to June 30, 2005)
United Nuclear yet again chasing cattle...
United Nuclear's fence problems at its reclaimed Church Rock tailings area are continuing. During environmental inspections performed in the second half of 2004, United Nuclear's inspector once again had to chase cattle out of the perimeter fence line:
Sep. 24, 2004: Chased two bulls out of the fenced tailings area
Oct. 26, 2004: Chased three bulls out of the east perimeter area
(Semi-Annual Effluent and Environmental Monitoring Report from July to December, 2004).
New Church Rock tailings fence line seriously damaged during floodings
A new 48'' field fence that had been installed in place of the previous barbed wire fence line to prevent further livestock entry, was damaged and downed a few weeks after installation during a major flood event on Sep. 9, 2003.
(Semi-Annual Effluent and Environmental Monitoring Report from July to December 2003; Feb. 11, 2004)
United Nuclear again chasing cattle...
United Nuclear still has problems with the fences at its reclaimed Church Rock tailings area. During environmental inspections performed in the first half of 2003, United Nuclear's inspector again had to chase cattle out of the perimeter fence line: he chased 6 cows and 9 burros on Jan. 16, and one cow and one calf on June 30, 2003.
(Semi-Annual Effluent and Environmental Monitoring Report from January to June 2003; Aug. 15, 2003)
United Nuclear chasing cattle...
During environmental inspections performed in 2002, United Nuclear's inspector had to chase cattle out of the perimeter fence line of the reclaimed Church Rock tailings area: he chased 6 herds of cattle on July 31 and "1 bull" (!) on August 27, 2002.
(Semi-Annual Effluent and Environmental Monitoring Report from July to December 2002; Feb. 19, 2003)
United Nuclear wants to halt groundwater treatment at Church Rock site
On November 4, 2002, United Nuclear's contractor Earth Tech, Inc., submitted a technical impracticability (TI) evaluation [!!] to support a request for a TI waiver for sulfate and total dissolved solids (TDS).
"Based on the results of the test, United Nuclear Corporation (United Nuclear) believes that sufficient data have been collected to demonstrate that natural attenuation mechanisms are more beneficial than the current corrective action at controlling the quality of groundwater for all key constituents of concern. Therefore, United Nuclear requests a decision from the agencies that the Southwest Alluvium system can be shut down permanently."
> View extension of groundwater plumes and proposed areas for institutional controls
(Fig. 7-1 from Second Five-Year Review Report for the United Nuclear Corporation Ground Water Operable Unit Church Rock, McKinley County, New Mexico, September 2003, US EPA Region 6)
On Feb. 13, 2004, EPA submitted its comments on UNC's Final Report and Technical Impracticability Evaluation, finding that the data provided by UNC is insufficient to support the conclusion that natural attenuation were more beneficial than the current groundwater corrective action.
Church Rock tailings cover deteriorates prematurely
Following a site visit on June 13, 2002, the U.S. DOE, in a letter dated July 3, 2002, notified the U.S. NRC of a number of concerns regarding early deterioration observed at the site:
Based on these observations, DOE feels that "significant annual maintenance at the Church Rock site will be required. [...] annual maintenance costs will be in the $10,000 to 20,000 per year range. These costs will be above and beyond what is normally required to maintain long-term care of a disposal site."
- A large amount of sediment had been deposited in the on-pile channels and in the other diversion channels.
- The slopes of the diversion berm appeared to be in a deteriorated condition caused by erosion and sloughing.
- Some rocks in the jetty along Pipeline Arroyo had been displaced.
- A gully had occurred on the side slope of the tailings pile at the southern end.
- Some differential settlement was noted in several areas on the top cover.
- Biointrusion of the cell cover was visible.
Environmental Protection Agency Meeting with United Nuclear Corporation, April 22, 1998
"On April 22, 1998, a representative from the Division of Waste Management
participated in an Environmental Protection Agency (EPA) Meeting with
United Nuclear Corporation (UNC), New Mexico Environmental Department, and
the Navajo Nation. The purpose of the Meeting was to discuss the EPA's
draft five-year review of corrective action at UNC's Churchrock uranium
mill site. UNC's Churchrock site is a Nuclear Regulatory
Commission-licensed superfund site currently undergoing corrective action
for a groundwater plume that developed from leachate generated by a uranium
tailings impoundment. UNC provided its comments on the draft as well as its
plans for site closure. The regulatory agencies provided comments on the
tentative closure plans, and discussed options available to UNC for site
closure including Alternate Concentration Limits and Technical Infeasiblity
waivers." (NRC Weekly Information Report for the Week Ending May 1, 1998)
NRC FINES UNITED NUCLEAR $100,000 FOR FAILING TO SET ASIDE
FUNDS FOR DECOMMISSIONING CHURCH ROCK URANIUM MILL
(Feb 14, 1997) "The Nuclear Regulatory Commission staff has
proposed a fine of $100,000 against United Nuclear Corporation,
of Gallup, New Mexico, for failing to properly comply with a
January 1992 order to set aside $16.4 million needed to
decommission and decontaminate the Church Rock uranium mill site near
Gallup." [NRC Region IV Press Relase 97/10]
> View Notice of Violation EA 93-170
> View background information on Uranium Mill Tailings Management - USA