Laserfiche WebLink
-56- <br /> Memo to Candace Thompson <br /> Coal Basin TR - Sutey Pile Phase II <br /> page 2 <br /> The coal processing waste structure is founded on an assemblage of <br /> low-permeability alluvial and colluvial surficial materials adjoining Coal <br /> Creek. As a result of its preliminary adequacy review of Phase I of the Sutey <br /> Coal Refuse Structure, the Division expressed a concern that low-permeability <br /> foundation materials might undergo an undrained failure, if loading rates <br /> exceeded those materials' ability to drain and consolidate. The applicant had <br /> not performed effective stress triaxial strength testing on the foundational <br /> materials and could not derive the parameters necessary to complete a <br /> sophisticated undrained effective stress analysis of the foundational <br /> materials beneath the proposed pile. As an alternative, the amended static <br /> slope stability analysis was based on a worst case assumption of instantaneous <br /> application of the entire structure's five year configuration load. Utilizing <br /> this worst case assumption, the amended analysis demonstrated, to the <br /> Division's satisfaction, that the proposed coal processing waste pile's <br /> foundation will provide adequate support under realistic anticipated rates of <br /> loading. This demonstration applies to the Phase II expansion of the <br /> structure. <br /> cc: Mike Long <br /> Doc. No: 0463F <br /> JP/jp <br />