Progress on Defense-Related Uranium Mines Program

Transcription

1 Progress on Defense-Related Uranium Mines Program Russel Edge US Department of Energy (DOE) Office of Legacy Management (LM) John Elmer Navarro Research and Engineering, Inc., Contractor to LM Uranium Recovery Workshop, June 2018 Merry Widow Mine, Eagle Basin, Colorado

2 Defense-Related Uranium Mine Sites In 2014, DOE estimated there were 4,225 defenserelated uranium mine (DRUM) sites, based on preliminary U.S. Atomic Energy Commission (AEC) records DRUM site is a uranium mine that produced ore for the AEC ore-buying program Production occurred between 1947 and 1970 Wedge 1 Mine, Eagle Basin, Colorado LM began verification and validation (V&V) of DRUM sites in

3 Program Objectives Develop a database of DRUM sites: Location and size Production quantities Complexity Potential hazards to humans and the environment Complete V&V of 2,500 DRUM sites by 2022 Present the risks and pathways identified to land management agencies to aid in prioritization and decision-making Unstable cabin at the Okie mine in Manti-La Sal National Forest, Utah 3

4 Background Majority of DRUM sites are on U.S. Bureau of Land Management (BLM) and U.S. Forest Service (USFS) lands Mines are accessed for recreation Mines present physical hazards for humans (and sometimes to wildlife) Rescue operation in 2017 at a mine shaft in Five Mile Pass area, Utah 4

5 Background (continued) Partnerships LM has entered into memorandums of understanding with BLM offices in Colorado, Wyoming, New Mexico, and Utah and the USFS Rocky Mountain Region LM has also entered into cooperative agreements with state abandoned mine lands (AML) programs in Colorado and Utah Some states have the ability to obtain inventory data on private, private/public mixed-owners, and state lands without access agreements AML programs have already inventoried and performed closures of openings on hundreds of DRUM sites 5

6 Background (continued) Approximately 4,225 uranium mines fit the DRUM definition More than half these mines produced less than 1,000 tons of ore About 20% are very small, producing less than 25 tons of ore Majority of DRUM sites are in Colorado and Utah New Mexico had the highest production DRUM sites by state DRUM Mine Volume and Production, Top Five States % Mines % Ore 0 Colorado Utah Arizona Wyoming New Mexico 6

7 Validation and Verification Primary steps in performing V&V: Mine location reconciliation Field inventory Environmental sampling Reporting Risk evaluation Initial results evaluated Conclusions Waste rock pile at Markey Mine, Red Canyon, Utah 7

8 Mine Location Reconciliation Each production record is evaluated Mine associated with each production record is located Locations are determined using a compilation of historic data records Some mines had production from more than one operator Duplicates are merged to one mine name and location LM is compiling a large collection of historic uranium maps and documents Merry Widow Mine, Eagle Basin, Colorado 8

9 Mine Location Reconciliation (continued) Information is gathered on previous reclamation activities, permits, and closures Determination is made on whether mine is on public land, private land, or mixed ownership Best access route to mine is plotted Geologist locating an adit on a small mine in the Yellow Cat District, Utah Field Operation Plan is prepared with all mines reconciled in a specific area (i.e., Uncompahgre Field Office, Colorado) 9

10 Field Inventory Verify or modify reconciled location of mine Verify closure status Geolocate (GPS) waste rock dimensions Identify potential migration pathways (typically drainages) Conduct initial gamma screening Record signs of human recreational use and visitation (e.g., campfire rings, tire tracks) Identify best access to mine site for sample team Geologist collecting inventory data 10

11 Field Inventory (continued) Geolocate (GPS), photograph, and record main site features: Openings (adits and shafts) Waste rock dumps Ventilation shafts Equipment and machinery Erosional features Total disturbed area Human use Trash and other debris Campfire ring at Johns Incline, Yellow Cat District, Utah 11

12 Environmental Sampling Soil and water sampling Determination of background Utilize a regional site if consistent geology in an area or site-specific when there is highly variable geology or remote site Soil samples Collected from all but the smallest waste rock piles (less than 100 square feet) Telluride 18 Mine, Yellow Cat District, Utah A 30-point composite sample is taken utilizing a screening protocol established by the U.S. Geologic Survey Analyze for 22 constituents of interest (e.g., arsenic, uranium) Only a few water samples have been taken to date No water present at most sites 12

13 Environmental Sampling (continued) Gamma Survey Utilizes a backpack-mounted gamma detector with GPS Provides real-time data Utilizes color-coding to represent range of elevated gamma Covers mine site and drainages, which are then bounded by background Utilizes foot spacing of transects Many areas are not accessible due to steep terrain 13

14 Environmental Sampling (continued) Ecological surveys Surveys of flora and fauna and their potential habitat on or near a mine Look for evidence of threatened, endangered, or special-status species Large raptor nest was discovered after seeing golden eagle fly out of an adit Raptor s nest, Raytex Mine adit, Long Park, Colorado 14

15 BLM Sensitive Species Findings Map of known occurrences of San Rafael milkvetch in Colorado San Rafael milkvetch (Astragalus Rafaelensis) Close-up of fruits (small pea pods) 15

16 Reporting Reports are developed for every DRUM site covering: Observational findings Photographs Maps and figures Analytical results Risk hazard and scoring Summary tables Soil sample results for East Wooden Shoe Group Mine, Deer Flats, Utah 16

17 Risk Pathways 17

18 Risk Scoring LM worked with BLM to assemble a risk scoring assessment system Risk levels are based on a recreational scenario of two weeks per year for 24 years Radiological risk is based on gamma survey compared to several established exposure limits Risk scoring process designed to provide flexibility to risk evaluator Purpose is to identify low- and high-hazard sites BLM will utilize multiple lines of evidence to evaluate a site s risk and to prioritize potential future actions Emphasis is to put mines in bins that pose similar degrees of risk 18

19 Example of Risk Scoring Risk ranking summary for the East Wooden Shoe Group Mine, Deer Flats, Utah 19

20 Initial Results Initial set of 113 mines evaluated for risk Mines located in Colorado, Utah, and New Mexico More than half of the mines produced less than 1,000 tons No large mines in data set New Mexico mine sites are typically larger and more complex General correlation with increased physical hazards and larger size Some smaller mines had significant physical hazards 58% of the mines ranked medium or high for physical hazards Collapsed wooden ore chute at the Tramp 2 Mine, Club Mesa, Colorado 20

21 Initial Results (continued) Closing adits has reduced the physical risks To date, only two very severe hazards have been identified that required immediate reporting to BLM Gray Fox Mine, Eagle Basin, Colorado with bat gate Large subsidence feature next to road, Daisy 2 Mine, Red Canyon, Utah 21

22 Initial Results (continued) Radiological and chemical risks are much lower than physical hazards based on the recreational use exposure scenario 35% of the mines rank low or none for all 3 primary hazards 22

23 Conclusions Mines visited have considerable diversity of physical hazards No mines to date have shown a high risk to human health or the environment Physical hazards are more significant than radiological or chemical hazards Reconciliation helps to better define population of DRUM sites Waste rock pile at Paradox Belle Mine, Long Park, Colorado V&V activities continue to demonstrate need to collect quality data to provide risk scoring assessments 23

24 Questions? Raptor watching, Tramp 2 Mine, Club Mesa, Colorado 24