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Ground Water. Table 15-8, Ground Water Monitoring Frequencies, Yoast Mine, presents frequencies
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<br />for ground water monitoring. Monitoring at wells in the Sage Creek basin was discontinued during the
<br />first five-year term, but has now resumed.
<br />SCC will discontinue the monitoring of several wells. Alluvial Wells YSAL7 and 9 are only ten feet
<br />apart from YSALB and therefore, will be discontinued. Wells YW7 to YWU13 IUSGS Numbers 7 to
<br />13, see Table 15-3, Summary of Ground Water Monitoring Sites, Yoast Minel exist at one location and
<br />are comprised of three Wadge overburden wells, three Wadge coal wells, and one Wadge underburden
<br />well. Water level monitoring will continue at this location for one Wadge coal well IYW71 and one
<br />Wadge overburden well IYOV91. In lieu of water quality sampling at the YW7 to YW13 well cluster,
<br />water levels and quality of the Wadge overburden, coal, and underburden will also be monitored at
<br />Wells YOV29, YW29, and YWU29, situated 650 feet to the north of YW7 and YOV9. Monitoring at
<br />Well YOV20 will be discontinued since it has filled in for collapsed) to a depth of 32 feet, which is
<br />higher than the top of the completion zone 156 feet). For similar reasons (see Table 1 5-3, Summary of
<br />Ground Water Monitoring Sites, Yoast Minel, Wells YW24 and YOV25 will also be discontinued.
<br />Wells YGAL17 and 18 will be discontinued since they are no longer in basins that are proposed to be
<br />disturbed. Wells YOV1, YW2, YLOV3, YLOV4, YL5, YL6, YOV20, YOV21, YOV22, YW23, YW26
<br />and YOV27 either have been or will be mined out. Wells YTC32 and 33 were never drilled. Well VTM
<br />32 replaces Well YTC32.
<br />Surface Water. Table 15-9, Surface Water Monitoring Frequencies, Yoast Mine, presents frequencies
<br />for surface water monitoring. Surface water monitoring was conducted at three sites during the initial
<br />period of the first five-year permit. Site YSGF5 monitors Grassy Creek downstream of the NPDESI 1
<br />discharges. Site YSG5 monitors Grassy Creek below the confluence of Scotchmans Gulch. Site
<br />YSAF4 was discontinued in 1996 and was replaced by Site VSA4. Site YSAF4 was located prior to
<br />the determination of the location of NPDESIO and, as a result, was placed 4000 feet upstream of the
<br />proposed NPDESI0 location. Site YSA4 was located below where this sediment pond was to be
<br />located and was discontinued upon construction of the pond. Two years prior to mining in the Sage
<br />Creek basin (which will not occur until the second five-year permit period), monitoring at Sites YSS2,
<br />YSSF2, and YSSF3 will recommence.
<br />S rp ings. Many of the springs noted at the Seneca II, Seneca II-W, and Yoast Mines exist in stream
<br />channels and are fed by alluvial ground water discharges. These alluvial springs would better be
<br />described as intermittent or perennial streams. At Yoast, Springs YSPG1, -2, -5, -7, -6, and -9 would
<br />• all fall into this category. It is SCC's belief that stream and alluvial well monitoring downgradient of
<br />these springs is sufficient. Therefore, monitoring will be conducted for those springs that are not in
<br />21 Revised 7/99
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