Laserfiche WebLink
<br />Memo to Dave Berry <br />Bowie No. 2 Third Supplemental Response <br />page 3 <br />1. Inclinometer Monitoring and Reporting <br />Mr. Stover amended the text of his introductory section to Volume VII to commit BRL to <br />the continued periodic collection and presentation of inclinometer data at the Bowie No. <br />2 mine site. This satisfies my concern. <br />2. Use of Filter Fabrics <br />Mr. Stover amended the text of his introductory section to Volume VII to clarify the <br />gradation of a "well graded filter blanket". Further, Mr. Stover clarified the use of filter <br />fabrics to cover open boulder rubble drains to minimize the migration of fines into the <br />drains. This satisfies my concerns. <br />3. Expansive Soils Shear Strength <br />In this instance Mr. Stover has chosen to decline my request for additional information <br />regarding the potential destabilizing effects of swelling soils. <br />In my earlier comment memo of January 14, 1997, I stated; <br />"In their original geotechnical engineering report, Maxim Technologies reported <br />that several soils exhibited volumetric expansion (under 500 psf fixed loads) of up <br />to 13 percent, correctly termed 'highly expansive'. Further, the author <br />appropriately commented; 'Clearly, most of the clays on this site would be <br />considered sensitive to loss of strength and/or volume change upon increases in <br />moisture content or pore pressure.' In my original adequacy memorandum I <br />observed; '...upon reclamation of the surface facilities extensive soil materials will <br />be unavoidably exposed to the elements. In their reclaimed configuration, swelling <br />and low-strength soils will be unconfined and exposed to extensive moisture. In <br />this configuration materials will exhibit their swollen, deteriorated 'ultimate' plastic <br />regime strengths. Reclaimed facilities will have to be designed and analyzed with <br />this fact in mind. The appropriate material strengths will have to be used in <br />determining the slope stability of reclaimed facilities, cuts and fills.' " <br />"Further, the author observed that the expansive soil materials will likely <br />significantly degrade in performance if wetted. One of the anticipated wet spots <br />in which Maxim projects the likelihood of encountering significant ground water is <br />in the area of the portal bench, where the highest cuts and slopes are projected <br />to be constructed. In my earlier adequacy comments 1 commented; <br />