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May 16, 2011 C-1982-057/Seneca II -W Mine SLB <br />The discharge riser (primary spillway) to Pond 0 1 6A has been damaged by ice on the pond surface during the <br />winter. The riser was torn at the point where the vertical and horizontal pipes meet, causing the pond to dewater at <br />the level of the horizontal pipe instead of the riser elevation. All discharge from the pond was flowing to Pond <br />016. There were two large cracks in the embankment of Pond 016A, having been caused by either the ground <br />movement in the area or the damaged spillway. There were also cracks between the Pond 016A outfall and the <br />inlet slope of Pond 016. Since Pond 0 1 6A had been dewatered by the damaged primary spillway, the risk of <br />embankment failure was lessened. The operator should not allow the water in the pond to rise above the damaged <br />spillway elevation, and should immediately pump the water out of the pond in the event that the level rises. The <br />operator has proposed to remove Pond 0 1 6A as part of the slide remediation plan currently under review (TR -73). <br />Since the pond will be removed, repairs to the pond will not be required at this time. Should the pond not be <br />completely dewatered and removed within 90 days of this inspection, repairs will be required. <br />Pond 016 was discharging very turbid water. A sample for settleable solids was taken in an Imhoff cone; after one <br />hour, there was a barely detectable amount of solids in the bottom of the cone, well below the 0.5 mlll standard. <br />The embankment of the pond was stable and well vegetated, and the outfall areas of both spillways were stable. <br />Postmining drainage channels that were accessible were in good condition and functioning as designed. All of the <br />major drainage channels were flowing at or near capacity due to the high snowpack and recent rains. <br />ROADS — Rule 4.03 <br />Construction 4.03.1(3)14.03.2(3) <br />Drainage 4.03.1(4)14.03.2(4) <br />'- Surfacing and Maintenance4 .03.1(5) and (6)14.03.2(5) and (6) <br />_Reclamation 4.03.1(7)14.03.2(7).• <br />A slide had occurred along the Mine Entrance Haul Road (MEHR) on the south side of the road. The slide is <br />approximately 200' in length, and originated at the top of the road embankment. The approximate location of the <br />slide is shown as "Area 1" in Figure 1 of this document. The movement of the embankment resulted in fill <br />material being pushed into and constricting the flow of Dry Creek. Severe erosion of the sidewalls has occurred in <br />the Dry Creek channel as a result of the constricted flow, and sedimentation has occurred offsite where material <br />from the road fill was washed into Dry Creek. An approximately 25 l.f. long section of the toe approximately 3' <br />thick had entered into and partially blocked the river channel. As a result, the Division issued Notice of Violation <br />No. CV2011 -001 for failure to ensure that "construction, maintenance, and post - mining conditions of haul roads <br />into and across the site of operations will control or prevent erosion and siltation, pollution of air or water, and <br />damage to public or private property ", as required by Rule 4.03.1(1)(a), and failure to ensure that haul roads do not <br />cause "additional contributions of suspended solids to strea nflow or to runoff outside the permit area" as required <br />by Rule 4.03.1(1)(b). An excavator was working during the inspection to pull the material out of the creek bed, <br />and a scraper and dozer were moving the material to the opposite side of the road. In addition to remediation of <br />the slide area, the operator was working to narrow the MEHR to the approved post - mining configuration. <br />Number of Partial Inspection this Fiscal Year: 9 <br />Number of Complete Inspections this Fiscal Year: 3 <br />Page 3 of 15 <br />