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The Issue: Human health related to uranium mining.
The Area: Vicinity around State Highway Route 566 and intersection with the Puerco River which is located approximately 17 miles northeast of Gallup, McKinley County, New Mexico.
The Inhabitants: Approximately 250 to 500 predominantly Navajo people live within two miles of the area. This area includes the Navajo Nation's Pinedale, Church Rock, Coyote Canyon, Standing Rock, Nahodishgish Chapters and the residences along Route 566 south of the mill site. The Red Water Pond Road Community lies between the Northeast Church Rock Mine and the Quivira Church Rock I Mine, just west of the Pipeline Canyon Road.
United Nuclear Corporation Mill Superfund Site - Section 2 contains the former uranium ore processing mill facilities and a byproduct material (tailings) disposal site which cover about 25 and 100 acres, respectively. Section 36 adjoins the southern border of the Navajo Reservation.
Two underground uranium mines were formerly operated in the vicinity of the Site. UNC operated the former Northeast Church Rock (NECR) mine, which is located to the northwest and adjacent to the Site, and Quivira (formerly Kerr-McGee) operated a mine to the north of the Site (Figure 2).
The UNC uranium mill was operated from 1977 to 1982. Uranium ore was processed at the facility using a combination of crushing, grinding, and acid-leach solvent extraction methods. The milling operation produced acidic slurry of ground rock and fluid (tailings) that was pumped into the tailings impoundments, into which an estimated 3.5 million tons of tailings were disposed.
Uranium Mines in the Area (see Figure 1):
Nearby Uranium Mines
Northeast Church Rock Mine (NECR) — is a former uranium mine that operated from 1967 to 1982. Most of the 125-acre mine permit area is held in trust for the Navajo Nation by the United States Government. Approximately 40 acres are patented mining claim land owned by the United Nuclear Corporation (UNC). There is a small community of residents that live immediately next to the mine site on the Navajo reservation, downstream and downwind of the waste piles. The residents graze sheep, cattle and horses, and collect herbs around the area. Due to the proximity of the residents to the mine site, this mine was identified as the highest priority for cleanup by US EPA and Navajo Nation EPA of over 500 abandoned uranium mines on the Navajo Nation.
The uranium ore body is located up to 1,800 feet below grade at the NECR Mine Site. Therefore, the mining was conducted over 1,000 feet below the ground surface accessed through two main underground shafts. Other mining features included several vent holes, support buildings, roads and water extraction wells and treatment facilities. Portions of the site are located within an arroyo. Approximately 3.5 million tons of uranium ore from the UNC mine was processed at the adjacent UNC Mill Site, located on private property across Highway 566.
Quivira Mines (Quivira Church Rock I and Quivira Church Rock IE) - are two former uranium mines that were operated by Kerr McGee Corporation (Kerr McGee) from 1974-1986. Rio Algom Mining LLC (RAML) received the property in 1985 and relinquished the lease in 1987. The Quivira mine areas contain abandoned uranium mines and are considered to be the major sources of the soil contamination at the Site. All the uranium ore from the mines, approximately five-million pounds, was processed at the Quivira Mining Corporation (QMC) Ambrosia Lake Mill located in Grants, New Mexico.
|Regulatory Agency||U.S. EPA Region 6 and Nuclear Regulatory Commission||U.S. EPA Region 9||
U.S. EPA Region 9
|Potential Responsible Party||UNC||United Nuclear Corporation (UNC)||
Rio Algom Mining LLC
|Land Owner||UNC||Navajo Indian Trust Land with 40-acres of patented mining claim land owned by UNC||
Navajo Indian Reservation
|Contaminants||Uranium, Radium, gross Alpha and Metals||Uranium, Radium and gross Alpha||
Uranium, Radium and gross Alpha
For more information, see the Contaminant Sources and Impacted Areas webpage.
The surface reclamation actions performed by UNC under the direction and oversight of the U.S. Nuclear Regulatory Commission (NRC) at the Site between 1988 and 1996 have stabilized the mill tailings and have protected the Rio Puerco from contamination spills like the one that occurred in 1979.
National Priorities Listing (NPL) History
NPL Proposed Date: 12/30/82
NPL Final Date: 9/08/83
|Location:||The Site is located 17 miles northeast of Gallup, New Mexico and on the southern border of the Navajo Indian Reservation.|
|Population:||The surrounding area is sparsely populated, with the nearest residence located 1.5 miles north of the Site.|
The Site includes a former uranium ore processing mill and tailings disposal area, which covers about 25 and 100 acres, respectively. The tailings disposal area is subdivided into three cells by dikes. The cells are identified as the South Cell, Central Cell, and North Cell. The tailings cells have been capped with an interim radon barrier cover as part of the reclamation activities directed by the NRC. Two evaporation ponds have been constructed on top of the cells as part of the EPA's ground-water remedy.
The surrounding lands include Indian Tribal Land, Indian Allotment Land and UNC-owned property. The land use near the Site is primarily grazing for sheep, cattle and horses. It is noted that the Ft. Defiance Housing Corporation, in conjunction with the U.S. Department of Housing and Urban Development and the Navajo Housing Authority, is planning to develop a 1000-unit housing complex, called the Springstead Estates Project, in the vicinity of Springstead (seven miles to the southwest of the Site).
Four water wells are within a 4-mile radius, the nearest being 1.7 miles northeast of the Site; however, nearby residents generally have used bottled water for drinking since the well water has a bad taste.
Hydrogeology: Three shallow water-bearing units beneath the Site were significantly recharged by mine water that was discharged into a local arroyo prior to and during Site milling operations. They are Zone 1 and Zone 3 of the Upper Gallup Sandstone Formations and the shallow alluvium (referred to as the Southwest Alluvium). These recharged units were then contaminated by tailings seepage from the Site. Underlying the Upper Gallup Sandstone Formation is the Mancos Shale. The Mancos Shale acts as an aquitard to prevent or retard the downward migration of contamination.
Acidic mill tailings, total dissolved solids, sulfate, thorium, radium, aluminum, ammonia, and iron.
Surface Soil Operable Unit Proposed Plan released July 20, 2012.
Preferred Alternative: On-Site Disposal at the UNC Site within the Tailings Disposal Area.
Public Comment Period: July 20, 2012 through September 21, 2012.
August 29, 2012
August 30, 2012
Octavia Fellin Public Library
Navajo Nation Superfund Office
Record of Decision
EPA signed the ROD on September 30, 1988.
- The selected remedy included:
- Containment and removal of contaminated ground water in the Southwest Alluvium and Zones 1 and 3 of the Upper Gallup Sandstone utilizing existing and additional wells.
- Evaporation of ground water removed from aquifers using evaporation ponds supplemented with mist or spray systems to enhance the rate of evaporation.
- Implementation of a monitoring program to detect any increases in the areal extent, or concentration of ground water contamination at, and outside of, the boundary of the tailings disposal area.
- Implementation of a performance monitoring and evaluation program to determine water levels and contaminant reductions in each aquifer, and the extent and duration of pumping actually required outside the tailings disposal area.
A Ready-for-Reuse Determination has not been made. The Site will be turned over to the Department of Energy for long-term care and monitoring of the tailings cells following closure.
Documents and Reports
4/11/2013 Administrative Record for United Nuclear Corporation Superfund Site
11/7/2012 NRC Final Comments on Surface Soil Operable Unit Proposed Plan
9/18/2012 UNC/GE Transmittal Letter for Comments
3/29/2013 Site Status Summary
3/29/2013 Fact Sheet
Five-Year Review Reports
9/2013 Fourth Five-Year Review
9/2008 Third Five-Year Review
9/2003 Second Five-Year Review
9/1998 First Five-Year Review
6/29/1989 Administrative Order - United Nuclear Corporation - Docket No. CERCLA 6-11-89
7/20/2012 U.S. Environmental Protection Agency Announces the Surface Soil Operable Unit Proposed Plan
Records of Decision
3/29/2013 Record of Decision for Operable Unit 2 Surface Soil Operable Unit
6/3/2014 Groundwater Flow Model of the Church Rock Site and Local Area, Church Rock, New Mexico – Revised Appendices
10/4/1979 Comments on Spill Response
5/13/2014 Ground Water Education Session #2
12/12/2013 Ground Water Education Session #1
8/30/2012 Transcript from Public Meeting.
8/29/2012 Transcript from Public Meeting
8/8/2012 TASC Meeting Minutes
|EPA Remedial Project Manager:||Janet Brooks||214.665.7598|
|EPA Community Involvement Coordinator:||Jason McKinney||214.665.8132|
|EPA Attorney:||James Costello||214.665.8045|
|EPA Region Public Liaison:||Donn R. Walters||214-665-6483|
|EPA State Coordinator:||Kathy Gibson||214.665.7196|
|New Mexico Environment Department:||Earle Dixon||505.827.2980|
|Navajo Nation Superfund Contact:||Eugene Esplain||928.871.7331|
|EPA Region 6 Superfund Toll Free Number:||800.533.3508|