U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Navajo Abandoned Uranium Mine Site Screen Report This form is for use at the site of abandoned uranium mines (A UM) located on Navajo Nation lands. Applicable sites include all mine and mine features that have or have not undergone reclamation by the Navajo Abandoned Mine Lands Reclamation Program, including features, adits, pits and waste piles. Applicable sites also include all AUM sites listed in the USEPA CERCLIS database, all sites listed in the 2008 AUM GIS Report issued by USACOE and USEPA, all A UM sites on allotment lands associated with the Navajo Nation, and any and all AUM sites not listed in any database located on Navajo lands. Reconnaissance of any sites located on lands adjacent to Navajo lands that may be impacting Navajo lands will need to be coordinated with the authorities appropriate to those lands. The purpose of the form is to ascertain the status and location of the identified A UM site, and record all immediate site information associated with the mine site. Decisions and recommendations on what additional steps are needed will be provided on a separate document. Mesa II1/2, Mine 4 AUM Site Navajo AUM Northern Region Prepared by: Weston Solutions, Inc. Contract: W91238-06-F-0083 12767.063.496.1111 March 2010 Mesa II 1/2, Mine 4, Mine ID # 604 1 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part I Site Identification, Location and Status Site Names and ID numbers as applicable Mine ID: 604 Map ID: N237 CERCLIS: NNN000908913 Navajo Abandoned Mine Land Reclamation Program: NA-0313 Local name / Aliases: Mesa 2 1/2-Mine #4 Chapter and local area: Cove Chapter County: Apache State: Arizona Lat/Long: 36.5150253553 N/-109.244201288 W Nearby road and highway: Indian Route 33 Local Post Office: Cove, AZ Surface Land Status: check one or more and provide ownership and contact information below Tribal Trust Land ^ Public lands EH Private EH Tribal Fee Land EH Bureau of Land Mgmt EH Allotment EH State EH Fee land EH Subsurface Mineral Rights: No information on subsurface mineral rights ownership was found in the EPA/AUM Database. Claim and operator information: The mine site surface land status is classified as Tribal Trust Land. Historical documents showed the operator of the mine as Kerr-McGee in 1952. No other historical ownership / lease information was identified in the EPA/AUM database. Number of residential structures within 200 feet of mine: None Estimated volume of mine waste onsite: 2,764 yd3 Mesa II 1/2, Mine 4, Mine ID # 604 2 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part II Summary of radiological readings Highest gamma radiation measurement: 276,859 counts per minute (cpm) Describe any other radiological measurements: A total of 2,044 gamma radiation measurements were collected from the mine site, ranging from 18,968 cpm to 276,859 cpm. Measurements in the vicinity of the waste debris were found at levels in up to 150,000 cpm, the drainage through site ranging from 137,000 - 275,000 cpm, and at the adit entrance at 75,000 cpm. The measurements are represented in Figures 1 and 2. Background Locations Average background = 10,289 cpm #1 10,289 cpm Distribution Chart and Statistics: The following chart and statistics were generated by ESRI ArcGIS 9.3.1, and show the general distribution of the site gamma radiation measurements. The horizontal X axis represents the gamma radiation reading levels in cpm (lowest levels to the left). The vertical Y axis represents the frequency of each gamma radiation level. Count: 2044 Minimum: 18968.00000 Maximum: 276859.00000 Sum: 134265684.00000 Mean: 65687.71233 Median: 57435,50000 Standard Deviation: 36526.17141 Mesa II 1/2, Mine 4, Mine 10 # 804 2 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part III Status of Reclamation and Mine Waste The following information was obtained from the Navajo Abandoned Mine Land Reclamation Program (NAMLRP) Point Features Database: NAMLRP Status of the mine site: Reclaimed : Yes Waste Pile onsite : Yes NAMLRP Project Number: NA-0313 NAMLRP Mine features: 1 Portal The following information was obtained from field observations collected during the 2009 site screening: Provide description and status of all mine sites and features at site. Include all waste piles, adits, pits and other features, and indicate whether they are open, closed, covered, capped, buried or unreclaimed. Indicate approximate size, shape and extent, including description of any reclamation caps. Note condition of all caps. Observed reclamation work and status: Adits Stone sealed adit Waste Piles Debris piles throughout the south end of the site: 150' x 50'; 75' x 75'; 30' x 60', with a total estimated volume of 2,764 yd3 Pits None Shafts None Other Debris and Mine Features Various mining debris was present at the site. The drainage running through the site had some running water, and starts at the adit in the adjacent site, Mesa III Mine. Drainage was followed until the slope became impassible. Mesa II 1/2, Mine 4, Mine ID # 604 4 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Part IV Site observations and Environs Navajo AUM Project Observed Structures: list number of and describe human habitation status of structures at the following distances from mine: 0 to 200 feet: None 200 feet to 0.25 mile: Observed Public or commercial structure: list and describe all schools, clinics, Chapter Houses, places of business and any other structure used by members of the community at the following distances: 0 to 200 feet: None 200 feet to 0.25 mile: None Levels measured around the perimeter(s) of the identified structure(s): All gamma radiation measurements collected in the vicinity of the house were less than 11,000 cpm Observed water sources: list the number and type of wells and surface water sources that are potentially used for human consumption at the following distances from the mine: 0 to 0.25 miles: Surface water draining from adit in Mesa III Mine site, east of site 0.25 miles to 4 miles: None Sensitive environments: note and describe all sensitive environments located within visible range of the mine site, including: wetlands, endangered species, habitats and approximate locations of sites that may be under protection of the government of the Navajo Nation. None observed Known Site History: include information from interviews with Chapter officials and residents. Note information on mine ownership, type of mining operation, period of operation, known amount of production, and any other information as provided. Mesa II 1/2, Mine 4 consists of an area of 10,737.09 m2. The mine was identified as being operational from 1952 to 1952. Historical documents showed the operator of the mine as Kerr- McGee in 1952. While operational, the mine had a total reported production volume of 114 tons. No other historical information or any additional ownership / lease information was identified in the EPA/AUM database. Mesa II 1/2, Mine 4, Mine ID # 604 5 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Part V Response Action Summary Site Name(s): Mesa II 1/2, Mine 4 Chapter: Cove Navajo AUM Project Decision Criteria Is there an unreclaimed waste pile at the site? Yes At what distance from the waste pile is the nearest residential structure located? At what distances from the waste pile are there potential drinking water sources? None Is there a reclamation cap or sealed adit in place at the site? Yes Is the cap/seal functionally intact? Yes Is the cap/seal sufficiently degraded to create a concern about releases? No At what distance from the cap/seal is the nearest domestic structure located? At what distance from the cap/seal is the nearest domestic drinking water source? None Summary of emergency response factors None Summary hazard ranking system factors None Summary of reclamation factors Unreclaimed waste piles, stone sealed adit; various mining debris was present at the site. The drainage running through the site had some running water, and starts at the adit in at the adjacent site, Mesa III Mine. Drainage was followed until the slope became impassible, elevated readings throughout drainage. Mesa II 1/2, Mine 4, Mine ID # 604 6 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part VI Photos Photo I. Mine site drainage Photo 2. Waste rock Mesa II 1/2. Mine 4. Mine 10 # 604 7 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Photo 3. Mining debris Photo 4. Waste pile Mesa II 1/2. Mine 4. Mine 10 # 604 8 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Photo 5. Drainage Photo 6. Drainage off site Mesa II 1/2. Mine 4. Mine 10 # 604 9 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Photo 7. Sealed adit Mesa II 1/2. Mine 4. Mine 10 # 604 10 March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Mesa II 1/2, Mine 4, Mine ID # 604 ^ \ March 2010 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part VII Contacts Reports and Information Name: Stanley Edison (928) 871-6861 Eugene Esplain (928) 871-7331 Title or official role (if any) Navajo EPA Superfund Program Address PO Box 2946. Window Rock. AZ 86515 Information provided Lead Regulatory Agency Name Title or official role (if any) Address Telephone number Information provided Name Title or official role (if any) Telephone number Information provided Name Title or official role (if any) Telephone number Information provided Mesa II 1/2, Mine 4, Mine ID # 604 12 March 2010 ------- Figure 1 - Gamma Radiation Measurements, Above Two Times Background Mesa II 1/2 Mine 4 (604) Cove Chapter, Navajo Nation, Arizona Legend Gamma Radiation Measurements • < 2X Backgound > 2X Background Gamma survey conducted 10/2009 Measured as counts per minute (cpm) Average background = 10,289 cpm Observed Adit Observed Waste Pile I Feet yyyy//1 Inaccessible due to steep grades —~ General Direction Down-Slope ~ Mine Claim Boundaries 150 £•» !<* 4fSHttir»EIJ ------- Figure 2 - Gamma Radiation Measurements Mesa li 1/2 Mine 4 (604) Cove Chapter, Navajo Nation, Arizona Legend Gamma Radiation Measurements • 0-10,000 • 10,000- 15,000 15,000-20,000 • 20,000-50,000 • 50,000- 100,000 • > 100,000 Observed Adit Observed Waste Pile inaccessible due to steep grades —~ General Direction Down-Slope ~ Mine Claim Boundaries Gamma survey conducted 10/2009 Measured as counts per minute (cpm) Average background = 10,289 cpm i Feet 150 ------- |