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(STATE OF CO ~ORAaO aiC~-aD o. L•W. ~•~^•' DEFAitTxifNi OF NATUaAL 0.ESOURGES D. Mona Pa~COa, Eaaartnt Diraetpr E 1FiINED LAND RECLA'VIATION y~~I i._.,-._ 423 Centennial building. t3t3 Sherman Street Denver, Coloretlo 80203 Tel.i303) 839-3567 June 30, I9BI TO: Bob Llddle FROM: Jim Pendleton David C. 5helton~ ~ `r Director , ~~~-~b ~,~,ab~' Jiff. 3198~~ .~ SUBJECT: Geotechnical as s. of Energy Feels xo. 3 Permit Rpplieatioa Pursuant to your request I have reviewed the Energy Fuels No. 3/Middle Creek pe_-manent program permit epp2ication. I fozward the following commenrs regarding the geotechniceI aspects of the permit: for your consideration. Grading and Backfilling The application states that it is the applicant's intent to backfil2 the surface pits and the portal area alt to approximate original contour, The - "'-" applicant further requests a variance from required ccn:emporaneous reclamation within the portal and surrounding area. The purposes for this request are to allow aortal access and to facilitate placement for underground waste rock (2 ft. of roof rack removed to assure roof stability) throughout the SG-year projected life span of the Middle Creek underground mine. ` The application is dufficient in two facets of its backfilling and grading proposal. First, the material bulking calculations are based upon very limited materials field density testing which utilizes "wet density" results. I do not believe this determination is sufficient. The applicant should conduct additional testing including determtination and comparison of results using dry material densities. Comparison of dry densities will eliminate the possibility of confusion due to moisture variation between the samples. The testing submitted within the application is limited to one in-place overburden test and approximately a half dozen spoil sample sites. The applicant should expand the testing program to include multiple ir.-place undisturbed overburden samples designed to test the representative overburden stratigraahic types. Furthermore, testing of disturbed spoil should include both the permanent and temporary overburden piles, which have been consclidated to varying degrees. Secondly, the application contains only a brief calculation of overall spoil bulking, including allowance for coal removal. The application should be amended to detail volume calculations far the separate project pits, the portal area and the permanent and temporary overburden piles. Further, a detailed calculation summary of the projected underground waste material volume should be included. This should allow verification of the applicant's statements re- garding the excess nature of the various overburden piles and veri °:cati.on of their projection of regraded approximate original contour.