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1 <br />' William J. Carter Mazch 12, 1998 <br />Re: Response to Susan Burgmaier's comments on the 1996 Annual Hydrologic Report <br />Division of Minerals and Geology as part of the submittal, and another copy of the report was <br />included in the 1995 Annual Hydrologic Report. <br />' Comment 3. <br />"Since 1990, total dissolved solids (TDS) values have risen steadily at SC-l . No mention or <br />' explanation is made in the report text. How does OCM explain this increase?" <br />' Response 3. <br />Monitoring wells SC-1 and SC-2 are designed to monitor the water level and quality of [he water in <br />the Rollins Sandstone which is 40 to 50-feet below the B-seam. Somerset Mining Company <br />' collected baseline monitoring data for SC-1 & SC-2 during 1991 before any substantial mining was <br />performed in the B-seam. Monitoring of SC-] and SC-2 after mining is performed in the B-seam <br />should confirm [hat the mining operation does not adversely impact the water in the Rollins <br />' Sandstone. The Rollins Sandstone is a confined aquifer as evidenced by water level measurements <br />in SC-1 & SC-2, which are well above the top of the sandstone member. It is very unlikely that the <br />mine workings which will be some 40 to 50 feet above the Rollins Sandstone will have any impact. <br />t A significant drop in the water level in SC-1 or SC-2 would indicate the mine may be having an <br />impact on the Rollins Sandstone. <br />' Monitoring well SC-2 was drilled from November 7 to November 11, 1990 to a total depth of 610 <br />feet, and into the Rollins Sandstone below [he coal seams. The bottom 110 feet of the hole was <br />' grouted and the monitoring well was installed to 500 feet. While drilling, water was encountered in <br />a rider coal seam in the vicinity of the D-Seam coal at a depth range from 127 to 130 feet. The <br />main D-Seam coal was logged at a depth range from 135 to 161 feet. <br />' After completion of well SC-2, another hole was drilled neazby to a depth of 168 feet for well SC-3. <br />Well SC-3 was installed to 145 feet in this hole. After completion of well SC-3, a third hole was <br />t drilled near the portals to a total depth of230 feet, and into the Rollins Sandstone for well SC-1. <br />Well SC-1 was installed to 230 feet in this hole. After completion of well SC-1 on November 19, <br />1990, monitoring of the wells was started on November 29, 1990. <br />High levels of electrical conductivity and total dissolved solids in the Rollins Sandstone wells, SC- <br />1 and SC-2, and high pH in SC-2, were of concern. On March 5, 1991, the driller returned to well <br />t SC-2, tripped 1-inch pipe into the well to airlift the well. Water bailed from the well continued to <br />be high in pH. The well was flushed with fresh water, and airlifted and bailed again. The well at <br />' that time was open to total depth at 500 feet. Also, the well was producing very little water during <br />this second attempt to develop the well. The water continued to be high in pH. On March 7, 1991, <br />the well was bailed several times, producing very little water and high pH, so the rig was taken off <br />' well SC-2. <br />' 6 <br />!\ <br /> <br />