2016-01-27_REVISION - C1981019 - Laserfiche WebLink

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topography by collecting elevation point readings along a predetermined transect of the parcel. No issues were observed. The group's second stop was at the Gulch A Ditch in the East Pit area of the permit. Gulch A Ditch is a permanent, trapezoidal, rip -rap armored channel with a sedimentation pond and NPDES outfall at its terminus. As part of SL -8, Tri-State applied for Phase I release on a 2.1 acre portion of the ditch. Reclamation work was performed between 1996 and 2002. DRMS verified postmine topography by collecting elevation point readings along a predetermined transect of the parcel. The group also measured for channel base width, channel top width, and channel depth at three different points approximately equidistant along its 3000 foot length (Figure 2). The measurements taken (channel base x channel top x channel depth) are as follows: 1. 13' x 28' x 30" 2. 16' x 36' x 40" 3. 15' x 33' x 34" No cutting or other issues were observed. The group's third stop was at the 29.5 acre East Pit area. Backfilling and grading, topsoiling, and reseeding were all conducted in 2014. The reclaimed East Pit displayed some vegetative establishment, though it was clearly less successful/mature than the 2013 reclamation work observed earlier at the West Pit. The surface of the reclaimed slope was generally stable, though minor rilling was observed on the south slope just above the toe where vegetation thins out (Figure 3). The operator had been made aware of this the week prior during an unrelated partial oversight inspection conducted by OSMRE. The operator committed then as well as during this inspection to monitor these rills and repair as necessary, balancing the need to contain hydraulic cutting with the surface redisturbance which comes with the use of heavy equipment to perform repair work. DRMS verified postmine topography by collecting elevation point readings along a predetermined transect of the parcel. No additional issues were observed. The group's fourth stop was at the 44.8 acre West Taylor Fill area. Backfilling and grading, topsoiling, and reseeding were all performed in 2011. The slopes of this parcel were stable and well vegetated (Figure 4). A portion of the rip rap armored West Pit Fill Ditch was included in the SL -8 bond release application and inspected at this time as well. The entire West Pit Fill Ditch was not proposed for Phase I release because, as with Gulch A Ditch, the watershed draining to these channels has not been entirely reclaimed. DRMS verified postmine topography by collecting elevation point readings along a predetermined transect of the parcel. No issues were observed. The group's final stop was at the 5.7 acre South Taylor Fill area. Backfilling and grading, topsoiling, and reseeding took place in 2013 and 2014. This parcel exhibited stable surface topography and an establishing vegetative community. DRMS verified postmine topography by collecting elevation point readings along a predetermined transect of the parcel. No issues were observed. The backfilling and regrading work I observed blended well with the surrounding topography and support the post mine land use of rangeland. With the exception of a portion above the toe of the south slope of the reclaimed Final East Pit, all inspected lands displayed excellent surface stability and drainage control, as well as varying degrees of successful vegetative establishment, based on time since reseeding. The minor rilling noted above will continue to be monitored by the operator for movement either toward self -healing or enlargement. In the case of enlargement, repair work will be performed. In either case, at this time these minor rills are not of a significance that would interfere with the Phase I bond release requested by Tri-State under SL -8. I recommend approval of Phase I bond release on the entire 189.6 acre parcel inspected this day.