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It ~ -- <br />1 <br />2 <br />3 <br />4 <br />5 <br />6 <br />7 <br />8 <br />9 <br />10 <br />11 <br />12 <br />13 <br />14 <br />15 <br />16 <br />17 <br />18 <br />l9 <br />20 <br />21 <br />22 <br />23 <br />24 <br />25 <br />26 <br />27 <br />,g <br />~q <br />30 <br />31 <br />To assess exposures to members of the public, DOE evaluated a stxaario in which an <br />individual camps on a mine:-tuck waste pile for 24 hours a day over a 14-day period. This <br />time period was used at the suggestion of EPA (L.ammering 1994). Lease tract 13 was <br />selected for assessment because it is the most accessible to the public and because of its close <br />proximity to State Highway 141 and the historical community of Slick Rock. Additionally. <br />this area is popular with vi:~itors for viewing desert bighorn sheep and for rafting the Dolores <br />River. The exposure value resulting from this scenario on lease tract 13 is considered <br />representative of the amount of radiation an individual could be exposed to at any other lease <br />tract because of the physical similarities of all the mine sites and mine-rock waste piles. <br />The TEDE resulting from exposure was estimated with RESRAD softwrur: (Argonne <br />National Laboratory 1993), which is a software package that performs random dose <br />calcutadons~ using pathway analysis. The calculated TIDE was 79 •ttrrem/yr, this value does <br />not exceed the NRC standard of 100 mrem/yr. The average value of 0.04 percent UrO,, ~~,~~ <br />derived from historic data a~lleaed on lease tract 13, was used in the random dose <br />calculations. Several asstunptions also were used in these caltxilations:. natural uranium was <br />assumed to be 99.28 percent uranium-238; the concentration of uranium-235 was assumed <br />to be 5 percent of the uranium-238 concentration (by activity); and uranium-235 and <br />uranium-238 were assumed eo be in equilibrium with their decay products. The exposure <br />pathways analyzed included szterml expcnuta_W 84, lion of contaminated <br />dust and radon (and radon dfxay prvdircts), and ingestion or ~ritiu~it'd~~'at3ff.'''~most <br />significant exposure pathway was extermal exposure from gamma radiation emitted from the <br />mine-rack waste pile, which caused 90 percent of the TIDE. <br />4.17.2 '_Yonradiological Hazards <br />Nonradiological hazards at th.e lease tracts that could pose a threat to human health include <br />unprotected mine openings such as adits. shafts. or inclines/declines. Currently, the lease <br />tracts posing the greatest risk to members of the public from the presence of physical hazards <br />are lease [racts 5. 6. 7, 9, 21. and 22A in the Paradox Valley area: lease tracts 11. 13. 13A. <br />14. and l5 in the Slick Rock area: and cease tracts 18. 19, and 25 in the Uravan area. <br />ULUP EA DOE Grwd .lunctinn Pmjrcts U[fcr <br />P~Fr 50 \fa~ I9. I'Mt5 <br />