2016-10-21_REPORT - M1980244 (31)

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Cripple Creek & Victor Gold Mining Company Squaw Gulch VLF Phase 1 Completion Record of Construction Report 475.0106.006 October 14, 2016 P:\Projects\0106.006 CC&V CQA and EDS\J‐REPORTS\ROC Report\475.0106.006 CCV PHASE 1 ROC REPORT ‐ FINAL161014.DOCX Page 5 specification. The development of the method specifications are described in Appendix D. All subgrade preparation and SF placement associated with site grading was monitored by the CQA Monitor to ensure that it met the project technical specifications. 2.5. Subgrade Preparation The subgrade was prepared and inspected prior to SLF placement. The exposed subgrade surface was moisture conditioned and primarily compacted using a 10‐ton smooth drum vibratory compactor. In areas where a steep slope existed, two smooth drum compactors mounted in tandem with a dozer were used to compact the subgrade. Ames also utilized a smooth drum compactor attachment mounted on an excavator on slopes where the two compactor and dozer configuration could not be used. Compaction of the subgrade was performed in accordance with the applicable developed method specification for the smooth drum compactor and excavator roller attachment presented in Appendix D. The CQA Monitor inspected and approved the finished subgrade surface prior to SLF placement. 2.6. Leak Detection Trench Approximately 6,775 linear feet of leak detection trench was constructed within the Squaw Gulch VLF Phase 1 Completion area in accordance with the project technical specifications. The as built layout of the leak detection trench is shown on Record Drawing No. 5. Detail V on IFC Drawing A260 shows the typical leak detection trench section. Per Detail V, a minimum one foot by one foot trench was excavated and lined with 40 mil smooth LLDPE geomembrane. The geomembrane was installed in long strips with a 5 foot overlap and was overlain by a 12 oz/yd 2 non‐woven geotextile. A 3‐inch diameter perforated corrugated polyethylene pipe (CPeP) was then placed in the trench. The trench was backfilled with Leak Detection Fill (LDF) and the geotextile was wrapped around the fill with a minimum 1 foot overlap. A minimum slope of 0.5 percent was maintained along the entire length of the trench. The CQA Monitor observed all leak detection trench installation. The Squaw Gulch VLF Phase 1 Completion leak detection trench was constructed by installing approximately 33,880 square feet of 40 mil smooth LLDPE geomembrane, 33,880 square feet of 12 oz/yd 2 non‐woven geotextile, 6,775 linear feet of 3‐inch CPeP, and 251 cy of LDF. Approximately 50 linear feet of 3‐inch solid HDPE (DR13.4) pipe was coupled to the perforated pipe and installed outside of the lined area to each 36” diameter HDPE manhole as shown in Details 5 and 8 on IFC Drawing A260.