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 (AUM) 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 AUM 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. Mine Name: Mexican Hat Stockpile Mine ID: 707 Navajo AUM North Central Region Prepared by: Weston Solutions, Inc. Contract: W91238-06-F-0083 20074.063.039.0020 April 2012 Mexican Hat Stockpile; Mine ID# 707 1 April 2012 ------- 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: 707 Map ID: NC2 CERCLIS: NNN000909311 Navajo Abandoned Mine Land Reclamation Program: None Local name / Aliases: None Chapter and local area: State of Utah County: San Juan State: UT Lat/Long: 37.1546554673 N / -109.856923882 W Nearby road and highway: Route 163 Local Post Office: Mexican Hat, UT Surface Land Status: check one or more and provide ownership and contact information below Tribal Trust Land ^ Public lands Q Private Q Tribal Fee Land Q Bureau of Land Mgmt Q Allotment Q State O Fee land Q Subsurface Mineral Rights: No information on subsurface mineral rights ownership was found in the EPA/AUM Database. Claim and operator information: No historical ownership / lease information or documents were identified in the EPA / AUM database. Number of residential structures within 200 feet of mine: None Mexican Hat Stockpile; Mine ID# 707 2 April 2012 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part II Summary of Radiological Readings Mine ID: 707 Highest gamma radiation measurement: 29,036 counts per minute (cpm) Background Average: 9,553 cpm Two Times Background: 19,106 cpm Describe any other radiological measurements: A total of 3,041 gamma radiation measurements were collected from the mine site, ranging from 6,317 cpm to 29,036 cpm. The measurements are represented in Figures 1 and 2. Distribution Chart and Statistics: Site Gamma Radiation Statistics Number of Readings 3,041 Minimum (cpm) 6,317 Maximum (cpm) 29,036 Mean (cpm) 11,015 Median (cpm) 10,626 Standard Deviation 2,324 Site Gamma Radiation Distribution 2,500 2,000 £ 1,500 Pi S 1,000 500 I I <10K 10K- 25K 25K- 50K 50K- 100K 100K - 250K 250K- 500K- 500K 1,000K Counts Per Minute (q)in) H < 10K H 10K-25K U25K-50K U50K-100K H 100K-250K H250K-500K ¦ 500K - 1,000K Mexican Hat Stockpile; Mine ID# 707 April 2012 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part III Status of Reclamation and Mine Waste Mine ID: 707 The following information was obtained from the Navajo Abandoned Mine Land Reclamation Program (NAMLRP) Point Features Database: NAMLRP Status of the mine site: Reclaimed: No Waste Pile onsite: No NAMLRP Project Number: None NAMLRP Mine features: None The following information was obtained from field observations collected during the 2011 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: None Observed Waste Piles: None Observed Pits: None Observed Shafts: None Observed Other Debris and Mine Features: Reclamation cap, approximately 50' x 150'; some debris/workings offsite Mexican Hat Stockpile; Mine ID# 707 4 April 2012 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part IV Site Observations and Environs Observed Residential Structures (number and human habitation status of structures at the following distances from the mine site): 0 to 200 feet: None Observed 200 feet to 0.25 mile: Observed Public or Commercial Structures (schools, clinics, Chapter Houses, places of business and any other structures used by members of the community at the following distances from the mine site): 0 to 200 feet: None observed 200 feet to 0.25 mile: 0.2 mi S - Fire house; 0.25 mi S - Town of Mexican Hat; Many oils tanks surrounding the site Levels measured around the perimeter(s) of the identified structure(s): Background Levels Observed Water Sources (number and type of wells and surface water sources that are potentially used for human consumption at the following distances from the mine site): 0 to 0.25 miles: 0.2 mi W - Reservoir; 0.25 mi SW - Reservoir 0.25 miles to 4 miles: 0.3 mi E - San Juan River Sensitive Environments (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 (information from interviews with Chapter officials and residents and database review, includes: mine ownership, type of mining operation, period of operation, known amount of production, and any other information provided): The Mexican Hat Stockpile mine claim consists of an area of 9,701 m . No additional historical ownership / lease information was identified in the EPA / AUM database. Mexican Hat Stockpile; Mine ID# 707 5 April 2012 ------- U.S. Environmental Protection Agency Region IX, San Francisco Navajo AUM Project Part V Response Action Summary Summary of Evaluation Factors: Accessibility: Was the mine easily accessible to potential human activity? Yes Radiological Measurements: Were any gamma radiation measurements collected at the mine greater than two times the site-specific background levels? Yes Waste Piles: Were any unreclaimed waste piles observed at the mine with gamma radiation measurements greater than two times the site-specific background levels? No Structures: Were any structures observed within 200 feet of the mine? No Potential Drinking Water Sources: Were any potential drinking water sources observed within 4 miles of the mine? Yes Reclamation: Was the mine reported to be previously reclaimed, or did the mine appear to be reclaimed? Yes Mexican Hat Stockpile; Mine ID# 707 6 April 2012 ------- G.S. Environmental Protection Agency Region IX, San Francisco Part VI Photos Navajo AtlM Project Mexican Hat Stockpile; Mine ID# 707 7 April 2012 ------- G.S. Environmental Protection Agency Region IX, San Francisco Navajo AtlM Project Photo 4 Mine Site #707 - Oil tank Mexican Hat Stockpile; Mine ID# 707 April 2012 ------- G.S. Environmental Protection Agency Region IX, San Francisco Navajo AtlM Project Mexican Hat Stockpile; Mine ID# 707 9 April 2012 ------- G.S. Environmental Protection Agency Region IX, San Francisco Navajo AtlM Project Photo 7 Mine Site #707- Oil tank Mexican Hat Stockpile; Mine ID# 707 10 April 2012 ------- U.S. Environmental Protection Agency Region IX, San Francisco Part VII Contact Reports and Information Navajo AUM Project Name: Title or official role (if any): Telephone number: Address: Eugene Esplain Navajo EPA Superfund Program (928") 871-7331 PO Box 2946, Window Rock, AZ 86515 Information provided: Lead Regulatory Agency Name: Title or official role (if any): Telephone number: Address: Information provided: Name: Title or official role (if any): Telephone number: Address: Information provided: Mexican Hat Stockpile; Mine ID# 707 11 April 2012 ------- Figure 1 - Gamma Radiation Measurements, Above Two Times Background Mexican Hat Stockpile (707) State of Utah Gamma Radiation Measurements • < 2X Backgound > 2X Background Measured as counts per minute (cpm) Average background 9,868 cpm Mine Site Boundary ~ General Slope Direction Observed Reclamation Feature I Feet 100 B i| l_S ^ f-tf Observed Waste Rock wgj (D Observed Adit ------- Figure 2 - Gamma Radiation Measurements Mexican Hat Stockpile (707) State of Utah "* \ Workings Gamma Radiation Measurements • 0- 10,000 cpm • 10,000 - 25,000 cpm 25,000 - 50,000 cpm 50,000 - 100,000 cpm • 100,000 -250,000 cpm • 250,000 -500,000 cpm • 500,000 - 1,000,000 cpm Mine Site Boundary General Slope Direction Observed Reclamation Feature Observed Waste Rock Observed Adit Average background 9,868 cpm Measured as counts per minute (cpm) m 3 ------- |