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COLORADO LEGACY LAND <br /> ' FORMER$CHWARTZWALDER MINE <br /> 1.4 RECORD CONSTRUCTION DRAWINGS <br /> The Record Construction Drawings consist of a topographic map of the finished grade and detail sheets showing <br /> as-built dimensions. The Record Construction Drawings prepared by Ensero, as well as an as-built surface <br /> provided by the Surveying Subcontractor, are presented in Appendix H. For comparison, the construction <br /> drawings are presented in Appendix G. <br /> 1.5 PROJECT DESCRIPTION <br /> The project site is located at the former Schwartzwalder Mine (the Site), located approximately six miles <br /> northwest of Golden, Colorado. The NWRP Diversion Channel construction activities included subgrade <br /> preparation, riprap placement, concrete work, liner (geoweb,geomembrane,and geotextile) installation and <br /> surveying. The project duration was from July to November 2020. This report covers the diversion channel <br /> construction activities monitored during the CQA program. <br /> 2 CONSTRUCTION OBSERVATIONS AND CQA SUMMARY <br /> Testing of the earthwork materials used in the construction of the NWRP Diversion Channel was performed in <br /> accordance with current American Society for Testing and Materials(ASTM)procedures.The requirements for <br /> testing frequency and test methods are presented in the Construction QA/QC Plan (Ensero, 2020),which was <br /> approved by DRMS under Technical Revision#28. Subgrade density and concrete testing was performed by <br /> AGW. CQA observations were performed by Ensero personnel. <br /> This section describes the QA/QC measures performed for all earthwork and channel construction activities. <br /> This work was completed in accordance with the Construction QA/QC Plan (Ensero, 2020) and documented <br /> with three technical inspections,conducted by DRMS: <br /> 1) August 4,2020: Headwall inspection <br /> 2) October 8,2020:Grading inspection <br /> 3) November 19,2020: Final inspection <br /> Copies of these inspection reports are included in Appendix A of this report. <br /> 2.1 EARTHWORK <br /> The channel alignment was excavated using a Caterpillar 320 Excavator below the channel invert grades in the <br /> design drawings. Clean subgrade material was then moisture conditioned and compacted in three lifts in <br /> accordance with the Technical Specifications providing a firm and unyielding subgrade for geotextile <br /> placement.In accordance with the Construction QA/QC Plan(Ensero,2020)compaction testing was completed <br /> every 100-feet for each lift. A minimum of 6 tests were required for each lift and a total of 18 passing tests were <br /> completed for the three lifts. Any unsuitable areas of subgrade were removed, replaced, and recompacted. <br /> Once adequate subgrade was built up above the channel bank elevation,the trapezoidal channel was excavated <br /> through the compacted subgrade along the entire alignment. Fill material classification and subgrade <br /> acceptance notifications are presented in Appendix E. <br /> DECEMBER 2020 3 NWRP CHANNEL RECORD OF CONSTRUCTION <br />