Laserfiche WebLink
Carbon Junction channel -The channel was in good shape with large rock riprap in place and the two 5 <br />'/z -foot diameter culverts extending underneath the haul road. The culverts contained no sediment, <br />indicating flow may not have yet occurred in the culverts. <br />Backfilline and Grading <br />Backfilling, grading, topsoil replacement, and seeding appeared to have been completed in all areas <br />within the permit azea except topsoil stockpiles 4, 7, and 8; the two sediment control ponds (1 and 2); <br />various ditches; the two sediment basins that are to be constructed at the base of North Pit in Cazbon <br />Junction Canyon (see page 5-6 of the reclamation plan); and various boreholes. The base of the North <br />Pit reclaimed slope is contoured to act as two stilling basins for runoff coming off of the slope, as <br />called for on page 5-6 of the reclamation plan. <br />Backfill on the northern edge of North Pit remains severely eroded where runoff from the adjacent <br />sandstone outcrop reaches the backfill. This erosion has been noted in previous reports. Drainage is <br />not yet adequately re-established at this location, as the reclaimed slope needs protection from runoff <br />coming off of the sandstone. <br />Drainage control. Pond 1 receives runoff from the north half of the North Pit reclaimed slope, the east <br />half of the PRSA, the South Pit Drill Pad, and the Equipment Yard. Runoff from the west half of the <br />PRSA reports to Pond 2. Runoff from the south half of the North Pit passes through a stilling azea at the <br />base of the reclaimed slope and then flows to the newly constructed Cazbon Junction channel via the ditch <br />next to the North Pit Haul Road. <br />Positive drainage appeared to exist throughout the drainage route from backfilled azeas to the ponds. The <br />completion of repair work was discussed during the inspection for the six locations in the SL-03 bond <br />release area where erosion has been excessive and/or repairs have been needed (Table 1). <br />Table 1-Drainage and erosional features <br /> <br />Location Erosional <br />Features Repairs discussed during <br />SL-3 bond release <br />inspection on 1117106 Repairs completed as of <br />current inspection <br /> Severe gullying Regrade, shape slope, and <br />North end of (described above in Place armor to protect <br />North Pit discussion of backfill from high velocity None <br /> backfill and runoff. <br /> radin <br /> Rock check structures have <br /> been installed in the rills <br /> Reduce flow velocity in rills and some rock has been <br />North Pit Three rills, each a by installing rock at upslope Placed at the upslope ends <br />backfill few hundred feet end of rills and at selected of the rills. Additional rock <br /> long locations in each rill. or vegetation is needed at <br /> the heads of the rills to <br /> reduce the velocity of water <br /> flowi~ into the rills. <br />4 <br />