The Quivira Church Rock Mines 1 (CR1) and 1 East (CR1E) are located approximately 16 miles northeast of Gallup, New Mexico, in McKinley County.  The reclaimed and closed uranium mine sites are located within the Navajo Nation.

The mine sites were operated by Kerr-McGee and Quivira Mining Company.  Rio Algom Mining LLC (RAML) is responsible for conducting the removal action.  Operations included exploration and development of two underground mines.  Ore was transported to the Quivira Ambrosia Lake facility for milling approximately 43 miles southeast of CR1 and CR1E.  Production operations ceased in 1983, and all surface structures were subsequently demolished and removed.  Sediment from on-site ponds was excavated and disposed in mine shafts and ventilation raises.  Waste piles at each site were covered with a minimum of 1 foot of soil and seeded with a local seed mix recommended by BIA.

Under an EPA administrative order on consent (AOC), Rio Algom initiated an interim removal action to secure the two mine sites and prevent migration of contaminants off site on October 5, 2010.

Church Rock, NM on Navajo Nation Reservation – EPA Region IX

1.1.2.2 Description of Threat
During the past 20 years, lack of site maintenance, intrusion by livestock, and local resident trespassing has led to overgrazing and a need for maintenance at the site. The poor coverage of vegetation at the CR1 site has contributed to the formation of deep erosion rills in the soil cap. Existing storm water control structures at both sites were identified as needing maintenance during the April 2010 inspection, and a need for additional storm water BMPs was identified. At the initiation of this interim remedial action, exposed soil material with elevated gamma activity was present at both sites and along RWPR north, south, and east of the bridge over the unnamed arroyo that borders the southern perimeter of the CR1 site. It is likely that some discharge of impacted material has also occurred to the adjacent unnamed arroyo.

1.1.3 Preliminary Removal Assessment/Removal Site Inspection Results
Recent characterization work associated with the nearby former North East Church Rock Mine suggests that the former mine access road and portions of the adjacent Red Water Pond Road (RWPR) were originally constructed using mine waste and or soils with elevated concentrations of radium -226 (Ra-226). Additional site characterization work performed by Weston Solutions Inc (Weston) in 2008 and 2009 on behalf of USEPA Region 6, and gamma activity levels measured during a site inspection in April 2010, suggest that the clean soil caps on the CR1 and CR1E waste piles are either failing or were constructed using material that does not meet the current USEPA action levels for Ra-226. Gamma readings ranging from below background to more than six times background were observed in the project area, with the west and southwest portions of CR1 along Red Water Pond Road being generally the most elevated.

Since the last field work, RAML completed the following:

• Finalized the Phase II Work Plan, 7 December 2010

• Submitted to EPA a draft report (February 2010) for Phase I IRA activities undertaken through December 2010

• Submitted to EPA a draft Stormwater Pollution Prevention Plan (SWPPP) (February 2011)

• Submitted to EPA an evaluation of drilling alternatives for planned subsurface soil and waste pile characterization investigations.

• Scheduled fieldwork to complete static and scanning gamma surveys, scheduled to begin March 14, 2011.  Earlier attempts were made during February to conduct this work; however, winter weather and wet soil conditions forced a rescheduling of this work.

Additional Characterization Work: Phase 2 Removal Assessment work is tentatively scheduled to resume in March 14, 2011 and last through the spring of 2011. The work is intended to characterize the lateral and vertical extent of selected potential contaminants of concern, including radioisotopes, petroleum hydrocarbons, and dioxins and PCBs.  Additional characterization work will occur at the CR1 and CR1E sites, and in areas adjacent to and downgradient from the sites, including in arroyos where process mine water and/or impacted sediments may have been discharged and/or wind-blown deposition of impacted dusts may have occurred.

RAML is expected to prepare and submit to EPA a technical memorandum that discusses the specific equipment, methods, and procedures to be employed for subsurface investigative work.

Sediment and erosion controls: Additional storm water BMPs are considered necessary. RAML now has a SWPPP.  RAML acknowledges that erosion control measures must be applied to the drainage along the shoulders of RWPR, and sediment basins and other BMPs need to be installed or modified during the spring and summer of 2011. 

Phase II site characterization investigation is expected to be completed and a report of the work submitted by September 30, 2011.  Pending the results of the characterization work USEPA expects that RAML will need to excavate at least some impacted areas at and near the CR1 and CR1E sites and consolidate them into existing waste piles. USEPA expects that clean fill material will be required to re-cap the existing waste piles. Regrading, additional erosion controls, and reseeding will likely be necessary to stabilize the sites.

1. USEPA expects that the measures discussed herein are interim in nature and that, pursuant to requests from the Navajo Nation Tribal Government, all mine wastes will eventually need to be removed from Navajo tribal lands.
2. The structural integrity of the RWPR Bridge remains a key issue. This is the shortest and easiest route for heavy equipment to enter the CR1 site.
3. Implementation of a SWPPP BMP installation, inspection, and maintenance plan is a key issue at the site.
4. RAML must still determine how they will conduct subsurface investigation of the unnamed arroyo.  EPA and RAML are unclear about how RAML will determine when they encounter native soil or to determine in the field when Ra-226 concentrations are below the action level of 2.24 pCi/g.
5. RAML still needs to investigate background sampling options and prepare technical memorandum that discusses it.
6. Excavation, removal, and consolidation of impacted soils from offsite areas, and recapping of existing soils as part of an interim remedial action to stabilize the waste pile and prevent continued discharge of impacted materials to the environment is considered necessary if final removal actions will not occur in 2011.

EPA 1, NNEPA – 0, START – 1, RAML/BHPB – 1 to 5, Senes – 4, BHP-Billiton – 1 to 2