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Mr. Jim Stover August 9, 1946 -New App./Bowie 2 Page 14 style stability analyses. Subsequent to the Division's issuance of its adequacy comments for the Bowie No. 2 Mine application, BRL submitted a "Preliminary Geotechnical Study" of the surface facilities area performed by Maxim Technologies, Inc., as a subcontractor to Morrison Knudsen, Inc. Having identified the proliferation of mass wasting problems throughout the proposed surface facilities area, Maxim performed extensive boring, sample collection and laboratory testing of materials at the site. Maxim characterized the general colluvial materials encountered throughout the site as a "Lean Clay with Gravel (CL-GC)", observing that "the majority of the overburden materials at this site can be described as a matrix of silty lean clay supporting scattered to numerous fragments of sandstone." WF.STEC referred to the corresponding colluvial cover on the processing refuse pile site as "the colluvial sandstone above the Mancos Shale". WF.STEC chose to convert from blow count observation conducted during penetration sampling, using procedures outlined by Peck, et. al. (1974) and Lambe & Whitman (1969), to deduce shear strength parameters (36° internal angle of friction and a cohesion of 0 psf') for the completion of their stability analyses. In our experience, blow count conversions can be suspect when penetration testing is performed on materials containing large fractions of competent cobbles which resist penetration. Maxim, having completed 23 bore angering program and sampling of the materials, chose to perform four triaxia] shear tests of the "Lean Clay with Gravel". Maxim's test results determined that at least two different material characters are manifested by this colluvial material, depending largely upon its clay constituency and degree of hydration. Undrained, unconsolidated triaxial compression tests performed on lower plasticity materials had an angle of intemal friction of 23 ° and an apparent cohesion intercept of 2,200 psf. However, higher plasticity materials displayed friction angles as low as 4° with an apparent cohesion of 3,050 psf. Materials with strengths similar to these highly plastic colluvial Lean Clays with Gravel will not result in acceptable SSF for the proposed refuse pile. Therefore, the Division continues to request additional information to verify WESTEC's assumed strength parameters for the 'colluvial sandstone above the Mancos Shale". The material could be sampled and tested, or Maxirn, if it examined the site, might be capable of rendering an opinion regarding the relationship of the waste pile colluvium to the materials it tested in completing its study. 2.05.4 -Reclamation Plan 2.05.4(2)(c) - Backfilling and GradinE 71) In responding to concern H27, BRL stated; "Slope stability analysis of the reclaimed slope will be performed based on the in progress M-K geotechnical study and submitted at a later