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Surface Drainage Modification Project 2 December 13, 1999 <br /> Project Completion Inspection CDPS No. CO-0044768 <br /> Consent Decree 94 Cv 5459 DMG File No. M-77-378 <br /> the previous ditch to allow the new ditch to be constructed entirely by fill. The previous <br /> ditch, constructed in tailings, was backfilled with native earthen materials and graded to <br /> direct drainage to the culvert inlet. The ditch was then lined with an impermeable liner. <br /> The liner was keyed into the slope of the embankment to ensure that slope drainage not <br /> undercut the liner. The liner was covered by approximately 12" of native soil, seeded and <br /> mulched. Application of mulch was complete except for a short stretch of the upper reach <br /> of the ditch. The finished ditch appeared well constructed and stable with sufficient <br /> capacity to function as designed. Borrow area for the fill and cap soil materials was <br /> located on the north side (upslope) of Tailings Pond 4. Additional comments on the <br /> borrow area are recorded below under "Additional Observations". <br /> The culvert under Highway 110 was a buried 24" diameter black plastic culvert. The <br /> culvert was double walled, inner wall was smooth, outer wall was annular. Two PVC <br /> pipes had been placed under Hwy 110, adjacent to the 24" ADS culvert. The additional <br /> PVC pipes were approximately 3" and 6" diameter and were apparently placed for future <br /> utility lines passing under Hwy 110. <br /> Additional Observations: The upland diversion ditch for Tailings Pond 4 was being <br /> extended in length to ensure diversion of all surface drainage around Tailings Pond 4. <br /> Dozer and excavator were present. Significant surface grading was occurring to ensure <br /> that the ditch excavation occur within a clay lens. The operator indicated that the clay <br /> lens extends at least 20' in depth. Excess materials were utilized to construct the <br /> sediment containment ditch, described above. <br /> Conclusion: Installation of the drainage control structures appeared consistent with SGC's <br /> November 8, 1999 report, and appeared to have been completed in accordance with the <br /> conditions of the Consent Decree and in accordance with the performance requirements of <br /> the Colorado Mined Land Reclamation Act and the Hard Rock/Metal Mining Rules and <br /> Regulations of the Colorado Mined Land Reclamation Board. <br /> cc: ♦ Allen Sorenson, DMG <br />