2004-10-18_REVISION - M1980244 (24)

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C. CONTRACTOR shall grade all excavations to enswe grades are maintained to provide adequate drainage at all times. Work shall be suspended by CONTRACTOR when, in the opinion of MANAGER and CERTIFYING ENGINEER, the site is overly wet, muddy, or otherwise unsuitable for proper maintenance, until directed otherwise by MANAGER, at no cost to CC&V. D. In excavations where Structuml Fill or Select Structural Fill is to be placed on slopes steeper than 3H:1V, horizontal benches shall be excavated into the slope to allow fill to be placed in horizontal lifts. The CONTRACTOR shall continuously bench and key embankment material into the existing material a minimum of 2 feet. E. The CONTRACTOR will be responsible for the safety of temporary construction slopes. CONTRACTOR shall inspect all temporary and permanent open-cut excavations on a regulaz basis for signs of instability. Should signs of instability be noted, CONTRACTOR shall immediately undertake remedial measwes and shall notify MANAGER immediately. Permanent cut slopes shall be left in smooth, safe, and stable condition at the end of the workday. F. CONTRACTOR shall final grade excavations within the valley leach facility to establish . positive drainage to the Pregnant Solution Storage Area. In no case will depressions or bowls be permitted in the valley leach facility azea. G. CONTRACTOR shall conduct all excavation and shoring operations in compliance with applicable MSHA, Colorado State and Federal government laws and regulations. • 3.05 SUBGRADE: A. The MANAGER and CERTIFYING ENGINEER wIll inspect and approve the exposed subgrade prior to any fill or Soil Liner being placed. CQA Monitor will confirni that the surface of the subgrade is smooth and free of debris, grade stakes, angulaz rocks, roots, branches, vegetation, mud, ice, or frozen material If the subgrade is determined to be frozen, using the criteria identified in Item 3.06.10 of Section 2200, the CONTRACTOR may either remove and replace the frozen subgmde or wait until subsequent temperature monitoring indicates the fill is unfrozen, at no cost to CC&V. The subgrade shall have no sudden sharp or abmpt changes in grade. B. CONTRACTOR is responsible for maintaining subgrades in a conditon satisfactory to CERTIFYING ENGINEER. CONTRACTOR shall protect prepazed subgrades, including previously approved subgrade, from weather, constmction equipment, or other factors as outlined in Part 3.06 of the SPECIFICATIONS. Subgrade surfaces, including previously approved subgrade, that become softened or otherwise unsuitable for placement of fill, shall be repaired to CERTIFYING ENGINEER'S and MANAGER'S sa[isfacfion, at no cost to CC& V. C. Prior to placement of fill materials, CONTRACTOR shall scarify all in-situ materials to a depth of 6-inches, moisture condition, and recompact the subgrade. Compactive effort shall be adequate to obtain a minimum of 95 percent of maximum dry density as determined by the standazd Proctor test (ASTM D698) for the particulaz fill material. Moisture conditioning shall be adequate to achieve a uniform moistwe and density. Tn rock azeas, the CONTRACTOR shall prepaze the subgrade by removing loose rock fragments until competent foundaton material is encountered as approved by CERTIFYING ENGINEER. I • D. If the underlying material is unsuitable to permit proper compaction of the subgrade, CONTRACTOR shall loosen, aerate (or excavate and remove), and recompact the subgrade until the top layer can be compacted as required. The recompacted surface shall then be scarified, as needed, to provide a good bond between the foundation and fill materials. Section 02200 Page 6 of 17 Mazch 22, 2000 Earthworks Golder Associates Revision 7 J.W9JOB5~043311pLLVC CERrb]CATfON REPOR'NHASE IVC OSA CERIWPPENDICiESAPPENDIX E rECkEJICAL SPECIFICATfoNS`U2200R] DOC