2010-10-21_REVISION - C1982057 - Laserfiche WebLink

Home Browse Search

generally followed the same path as the designed channel. The as-built channel is approximately 165 feet shorter than design because it does not go up the slope as far as the designed channel. Additionally, the as-built channel has a fork at the upper end, where the channel design shows it being straight. The lower portion of the channel, below stock tank T-27, was well vegetated and stable with very little erosion. There was more erosion in and around the channel above stock tank T-27 and Seneca was fixing this area, including portions of the channel, at the time of the inspection. There are also a three surge pond in channel PM-2A, one at station 6+84, one at station 16+06 (just below stock tank T-27) and one at station 19+59 (just above stock tank T-27). There was some erosion entering and exiting stock tank T-27 and the surge pond at station 19+59, above the stock tank, which Seneca has fixed. This area above stock tank T-27, including the entire channel above the stock tank, is being considered for exclusion from the Partial Phase I Bond Release SL-03 application due to rill and gully and channel erosion problems. The as-built channel profile is between six and 40 feet lower than the design profile due to changes in the post-mining topography and the resulting change in the channel's alignment. Overall, the grades of the as-built channel, although not exactly the same as the designed channel, do approximate those of the designed channel. There was also a spoil spring observed flowing above station 7+97. The following chart shows the GPS data for post-mining channel PM-2A. GPS Height Northing Easting Z Corr. Correct Z Exh D Elev. Z Diff. Exh 20- 5.9 Station 7511.0 4470020.0 309948.1 40.620 7551.654 7516.9 4470016.7 309956.9 40.620 7557.487 7566 8.513 7600 0+00 7549.1 4469935.8 309986.1 40.620 7589.753 7592 2.247 7615 2+82 7588.9 4469848.4 310014.7 40.620 7629.557 7630 0.443 7649 5+83 7596.8 4469818.2 310018.1 40.620 7637.456 7642 4.544 7653 6+84 7604.3 4469783.4 310017.1 40.620 7644.965 7648 3.035 7660 7+97 7646.4 4469643.9 310053.4 40.620 7687.069 7690 2.931 7722 12+71 7661.9 4469611.9 310068.7 40.620 7702.510 7706 3.490 7762 13+87 7714.1 4469546.4 310076.2 40.620 7754.710 7752 -2.710 7809 16+06 7729.2 4469526.5 310080.1 40.620 7769.844 7768 -1.844 7820 16+76 7730.3 4469490.9 310080.2 40.620 7770.957 7778 7.043 7836 17+92 7782.2 4469417.4 310089.6 40.620 7822.825 7816 -6.825 7858 19+59 7784.2 4469440.5 310086.3 40.620 7824.806 7828 3.194 7869 20+36 7826.7 4469343.4 310105.8 40.620 7867.326 7868 0.674 7927 22+84 7842.4 4469314.5 310121.2 40.620 7883.054 7886 2.946 7942 23+91 7865.9 4469277.2 310125.9 40.620 7906.560 7906 -0.560 7965 25+15 7910.3 4469213.9 310123.8 40.620 7950.899 7950 -0.899 7984 27+23 7925.7 4469204.5 310150.3 40.620 7966.275 - Channel PM-2B runs approximately 500 feet east of channel PM-2A and flows in a northwest direction, intercepting channels PM-2 and PM-3 and discharging into Pond 016A. The as-built length of the channel is approximately 2,170 feet and the designed