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Memo to Dave Berry <br />Bowie No. 2 Geotechnical Adequacy Responses <br />page 5 <br />Lambe & Whitman (1969), to deduce shear strength parameters (36° <br />internal angle of friction and a cohesion of 0 psf) for the completion of <br />their stability analyses. In my experience, blow count conversions can be <br />suspect when penetration testing is performed on materials containing <br />large fractions of competent cobbles which resist penetration. Maxim, <br />having completed an entailed 23 bore augering program and sampling of <br />the materials, chose to perform four triaxial shear tests of the "Lean Clay <br />with Gravel". Maxim's test results determined that at least two different <br />material characters are manifested by this colluvial material, depending <br />largely upon its clay constituency and degree of hydration. Undrained, <br />unconsolidated triaxial compression tests performed on lower- plasticity <br />materials had an angle of internal friction of 23° and an apparent cohesion <br />intercept of 2,200 psf. However, higher plasticity materials displayed <br />friction angles as low as 4° with an apparent cohesion of 3,050 psf. <br />Materials with strengths similar to these highly plastic colluvial Lean <br />Clays with Gravel will not result in acceptable SSF for the proposed <br />refuse pile. Therefore, the Division continues to request additional <br />information to verify WESTEC's assumed strength parameters for the <br />"colluvial sandstone above the Mancos Shale". The material could be <br />sampled and tested, or Maxim, if it examined the site, might be capable of <br />rendering an opinion regarding the relationship of the waste pile <br />colluvium to the materials it tested in completing its study. <br />71. In responding to concern #27, BRL stated; "Slope stability analysis of the <br />reclaimed slope will be performed based on the in progress M-K <br />geotechnical study and submitted at a later date." BRL hired Morrison <br />Knudsen (M-K) to address the geotechnical stability of the proposed <br />surface facility area of the Bowie No. 2 Mine. M-K, in turn, subcontracted <br />with Maxim Technologies, Inc., to complete a geotechnical investigation of <br />the site. The Division's primary responsibility regards the geotechnical <br />stability of the proposed reclaimed configuration. If the Division cannot <br />find that the mine site can be returned to a beneficial use the permit <br />cannot be approved. <br />