|
Ground W ater. Table 15-8, Ground Water Monitoring Frequencies, Yoast Mine, presents frequencies for
<br />ground water monitoring. Monitoring at wells in the Sage Creek basin was discontinued during the first five-
<br />year term, but has now resumed.
<br />SCC will discontinue the monitoring of several wells. Alluvial Wells YSAL7 and 9 are only ten feet apart
<br />from YSAL8 and therefore, will be discontinued. Wells YW7 to YWU13 (USGS Numbers 7 to 13, see Table
<br />15-3, Summary of Ground Water Monitoring Sites, Yoast Mine) exist at one location and are comprised of
<br />three Wadge overburden wells, three Wadge coal wells, and one Wadge underburden well. Water level
<br />monitoring will continue at this location for one Wedge coal well (YW7) and one Wadge overburden well
<br />(YOV9). In lieu of water quality sampling at the YW7 to YW13 well cluster, water levels and quality of the
<br />Wadge overburden, coal, and underburden will also be monitored at Wells YOV29, YW29, and YWU29,
<br />situated 650 feet to the north of YW7 and YOV9. Monitoring at Well YOV20 will be discontinued since it
<br />has filled in (or collapsed) to a depth of 32 feet, which is higher than the top of the completion zone (56
<br />feet). For similar reasons (see Table 15 -3, Summary of Ground Water Monitoring Sites, Yoast Mine), Wells
<br />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, YLS, YL6, YOV20, YOV21, YOV22, YW23, YW26 and
<br />YOV27 either have been or will be mined out. Wells YTC32 and 33 were never drilled. Well YTM 32
<br />replaces Well YTC32.
<br />Surface Wat er. Table 15 -9, Surface Water Monitoring Frequencies, Yoast Mine, presents frequencies for
<br />surface water monitoring. Surface water monitoring was conducted at three sites during the initial period of
<br />the first five -year permit. Site YSGFS monitors Grassy Creek downstream of the NPDESII discharges.
<br />Site YSG5 monitors Grassy Creek below the confluence of Scotchmans Gulch. Site YSAF4 was
<br />discontinued in 1996 and was replaced by Site YSA4. Site YSAF4 was located prior to the determination of
<br />the location of NPDESIO and, as a result, was placed 4000 feet upstream of the proposed NPDES10
<br />location. Site YSA4 was located below where this sediment pond was to be located and was discontinued
<br />upon construction of the pond. Two years prior to mining in the Sage Creek basin (which will not occur until
<br />the second five -year permit period), monitoring at Sites YSS2, YSSF2, and YSSF3 will recommence.
<br />Springs 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 described
<br />as intermittent or perennial streams. At Yoast, Springs YSPG1, -2, -5, -7, -8, and -9 would all fall into this
<br />category. It is SCC's belief that stream and alluvial well monitoring downgradient of these springs is
<br />sufficient. Therefore, monitoring will be conducted for those springs that are not in
<br />23 Revised 7/99
<br />
|