2011-10-06_REVISION - M1980244 (3)

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3.04 EXCAVATION: Section 02200 Earthworks ame A. CONTRACTOR shall perform excavation to the lines and grades shown on the DRAWINGS or as directed by MANAGER. No excavation shall begin until the CONTRACTOR has provided construction staking for the proposed work. B. CONTRACTOR shall prevent the disturbance of surrounding areas during excavation. Where selective excavations are required to obtain materials for Structural Fill and Select Structural Fill, the material removed from the excavations shall be taken directly to the fill areas or, if required, stockpiled by material types. The stockpiles shall be approved by MANAGER. C. CONTRACTOR shall grade all excavations to ensure 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 Structural Fill or Select Structural Fill is to be placed on slopes steeper than 3H:1 V, 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 regular basis for signs of instability. Should signs of instability be noted, CONTRACTOR shall immediately undertake remedial measures 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 area. 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 confirm that the surface of the subgrade is smooth and free of debris, grade stakes, angular 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 subgrade 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 abrupt changes in grade. B. CONTRACTOR is responsible for maintaining subgrades in a condition satisfactory to CERTIFYING ENGINEER. CONTRACTOR shall protect prepared subgrades, including previously approved subgrade, from weather, construction 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 satisfaction, at no cost to CC &V. S:\Projects \1125G Squaw Gulch Valley Leach Facililty Design \I - Tech Specs \02200.r0.doc Page 7 of 18 January 14, 2011 Revision 0