2022-02-09_PERMIT FILE - M2021046 (4)

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amec foster wheeler Zephyr Gold USA Ltd. PAGE 7 OF 11 Dawson Gold Project Dawson Filtered Tailings Storage Facility SPECIFICATION SEC. NO.: 01400.1 Pre-feasibility Study TECHNICAL SPECIFICATIONS FOR EARTHWORKS DATE: (ORIGINAL) Fremont County, Colorado CONSTRUCTION QUALITY ASSURANCE(CQA) 20-October-16 PROJECT NO.: 74201633 PLAN REVISION: A DATE: 20-Oct-16 constructed and existing structures. The CQA MONITOR(S)will record visual observations throughout the construction process to ensure that the materials are placed to the minimum dimensions as shown on the DRAWINGS. 6.1 FOUNDATION PREPARATION The CQA MONITOR(S)shall observe and document the foundation preparation including: • Initial Foundation Cleaning: Stripping and excavation activities required to remove any unsuitable materials such as loose or embedded rock, soft soils or tailings, organic material, and any other deleterious material (such as debris, roots, branches, vegetation, or mud). The CQA MONITOR will document that any unsuitable materials, as determined by the ENGINEER, are removed and placed in an appropriate stockpile facility. • Stockpiling activities to include verification of location of stockpile, material type, and dressing. • Excavations for seeps, unsuitable foundation soil, elevation, and proper drainage. • Foundation subgrade preparation to confirm that the surface of the subgrade is free of soft, organic, and otherwise deleterious materials, and that soil and rock surfaces that contain joints or fractures are adequately filled in accordance with the SPECIFICATIONS. • Construction of access roads, site grading, drainage control features and erosion control features to verify compliance with the DRAWINGS and SPECIFICATIONS. 6.2 PLACEMENT OF MATERIALS During placement of any engineered fill such as Rockfill, Structural Fill, Geomembrane Cushion Material, Filter Material, Drain Gravel, and Riprap, the CQA MONITOR(S)shall: • Verify the use of appropriate fills. • Monitor and document that the material placement, including soil type, particle size, loose lift thickness, moisture conditioning process, compaction equipment, methods used to attain compaction, including number of passes, uniformity of compaction coverage, compacted lift thickness, bonding of lifts, in-place moisture content and dry density is in compliance with the SPECIFICATIONS. • Monitor surface preparation to verify that the soil surface is suitable for geomembrane installation as discussed in the SPECIFICATIONS. • Monitor the soil placement to confirm that they comply with the SPECIFICATIONS. S:\ZEPHYR MINERALS\DRMS MINE APPLICATION\01400.1-EARTHWORKS CQA.DOCX