2019-08-23_REVISION - M1980244 (5)

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Cripple Creek&Victor Gold Mining Company Squaw Gulch VLF Phase 2A Part 1 ■ Record of Construction Report 475.0106.032 August 21,2019 Volvo A30 Haul Truck Edge TRT622 Trommel CAT 740 Haul Trucks Tandem Axle Water Trucks CAT 777 Haul Trucks CAT 740 Water Truck CAT 773 Water Wagon 2.1. Clearing and Grubbing The footprint of the Phase 2A Part 1 Squaw Gulch VLF was stripped of all deleterious materials. Any soil containing vegetation was removed and placed in several site topsoil stockpiles designated by CC&V. All cleared areas were inspected by the CQA Monitor to ensure that all deleterious material was removed prior to further construction activities. 2.2. Underground Working Remediation Historic underground workings within the Squaw Gulch VLF Phase 2 footprint were remediated in accordance with IFC Drawing A38 and the project Technical Specifications. IFC Drawings, A30 through A38, present all historic underground workings that were known at the start of construction. All underground workings that were encountered within the Phase 2 limits during construction were given a unique identification number and are summarized in the table presented in Appendix D.1. The table includes the historic identification number, identification number, location (northing, easting, and surface elevation), type of working, remediation type, remediation quantities and remarks regarding the remediation. Workings were only identified if they were within 50 feet of the finished subgrade surface. Investigation and remediation were not required for any workings that exist at a depth greater than 50 feet below the finished subgrade surface. Appendix D.2 contains a layout of all underground workings that were remediated within the Phase 2 limits. 2.2.1. Confirmatory Drilling Confirmatory drilling was performed at all workings that were known or encountered during Phase 2 construction in order to help define the limits of the working. The goal of the confirmatory drilling was to isolate the working so that the proper remediation could be completed. Pneumatic hammer track drill rigs were used to drill three-inch diameter holes, on a 4- foot grid, to a depth of 50 feet from the pad finished grade elevation. If drilling activities indicated that 50 feet of crown pillar existed above the working, then the drill hole was marked as a "miss." If any voids were encountered during drilling, then the drill hole was marked as a "hit," and the void depths were recorded. After the working was encompassed by "misses," a remediation plan was developed for the working. P:\Projects\0106.032 VLF2 Phase 2 CQA\1-REPORTS\Cert Report-Phase 2A Part 1\DRMS Comments\475.0106.032 CCV PHASE 2A Part 1 ROC REPORT_Revl.docx Page 2