_INSPECTION - C1994082 (87) - Laserfiche WebLink

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III. COMMENTS - COMPLIANCE Below are comments on the inspection. The comments include discussion of observations made during the inspection. Comments also describe any enforcement actions taken during the inspection and the facts or evidence supporting the enforcement action. General Comments This was an aerial inspection of the Seneca Yoast Mine. The site was flown on the afternoon of 5/29/08, and Harry Ranney of the Division took 26 oblique and near vertical digital image photos. The images were viewed by Dan Mathews of the Division on 6/04/08. Snow had very recently melted in most areas, although there were scattered remnant patches in drift locations. Most areas appeared muddy, with standing water from recent melt in low lying areas; most ponds and sediment ponds were full or nearly full. The snow pack was heavier than normal in the mine area this year, and snow cover persisted longer than is typically the case. Saturated soil conditions from the melt have likely contributed to minor slumps and ground settling observed in several locations, as well as the significant slope failure near Pond 12, described in the April inspection report, for which NOV CV-2008-001 was issued. Heavy runoff from snow melt has resulted in rill and gully erosion in various locations on recently reclaimed hillslopes, as well apparent erosion in some locations along reclaimed permanent stream channels. Due to the very recent melt off in most areas, vegetation has only recently initiated spring growth. A number of locations in addition to the Pond 12 slide were observed where erosion or settlement related maintenance will be necessary this field season. Areas of erosion or apparent instability that will need to be ground checked and that will likely require remedial work this field season are briefly discussed below. The Pond 12 slide is not discussed due to the detailed description included in the April inspection report. Due to incomplete photo coverage, and difficulty making detailed observations based on the aerial images, this is not intended to represent a comprehensive listing. • An area of significant concern was noted along and adjacent to Channel YPM-8, near its confluence with the large Annan Draw tributary. There appears to have been substantial erosion both in and adjacent to the lower end of the permanent channel in this location. The circumstances that resulted in the erosion and the extent of damage will be assessed during the next site inspection. Channel repair, slope regrading, topsoil replacement and seeding will be warranted in the area impacted by erosion. Drainage from this location reports to Sedimentation Pond 10, on Annan Draw. • A sinkhole feature was evident on a recently reclaimed area immediately west of the junction of YPM 19 and YPM 6-1, in the upper Pond 12 watershed. It appears that the feature may be approximately 15 feet in diameter and at least 6 to 10 feet deep. Circumstances and apparent cause will be investigated during the next field inspection. The hole will need to be properly backfilled. • A prominent hillslope gully was noted a short distance to the south of YPM Channel 7A. Lesser hillslope gullies and areas of rill erosion were observed in various locations on recently seeded steep slope sites. Apparent channel scour was noted along several permanent channel segments, including YPM 6-1, YPM-7, YPM-7A, and YPM-14 (in addition to the erosion along YPM-8). Gully remediation in accordance with the approved rill and gully plan and permanent channel repairs to restore the channels to design condition will need to be implemented in a timely manner during the field season. 3