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Mr. Kent Gorham <br />October 21, 1996 <br />Page 5 <br />Response: TCC acknowledges its commitment to monitor additional Trout Creek Sandstone wells in <br />the event inflows from the Trout Creek Sandstone to the mine workings are encountered. TCC maintains <br />its position that no such inflows have been encountered and consequently, no additional monitoring has <br />been conducted. The referenced statement from the 1995 AHR with respect to well 006-83-48C was not <br />intended to suggest that the observed decline was attributable to mining operations. Rather, the statement <br />was a generalized observation regazding the overall trend exhibited by the well during it's period of record. <br />The data associated with well 006-83-48C indicates the declining trend at this site begins in early 1986 and <br />continues through October 1991. Longwall mining in the western portion of the mine commenced in late <br />1989. Water levels during the year and a half period immediately prior to direct undermining of the well <br />are shown to be increasing. <br />Other monitored Trout Creek Sandstone wells have shown no marked decrease ur water level with the <br />exceptions of a well that is pumped (001-83-106) or in close proximity to a pumped well (001-83-107). <br />Updated figures incorporating 1996 data are included for your information. Be advised that the plotted <br />points for the new well 95M001 are based on an estimated measuring point elevation as this site has not <br />been surveyed to date. Figures 15, 16, 17, 18, and the un-numbered figure for well FBR-2-E enclosed <br />herein are for informational purposes only and are not intended to replace previously submitted information <br />in the 1995 AHR. <br />Mine Inflow Monitorin <br />1. Field parameters reveal variable water quality from inflows in the gateroads of the Eastern Mining <br />District. Conductivities range from 1018 umhos/cm at point 16 along the fault to 9340 umhos/cm at point <br />15 some 1200 feet away. What would account for this variability of conductivity? What is the source of <br />the inflow along the fault located in IOR and 9R gateroads? <br />Response: The conductivity depicted on Figure 93 at point 16 in the 9R gateroad is erroneous. The <br />correct value should read 934. The conductivity was originally recorded as 9340. This unusually high <br />value was noted ,the site was revisited approximately one week later, and the conductivity measured at that <br />time was approximately one order of magnitude lower. TCC believes the instrument scale was simply <br />misread during the first visit. This correction was not conveyed to the draftsman who generated Figure 93 <br />based upon the originally collected data. Corrected copies of Figure 93 are enclosed and should replace <br />those originally submitted. <br />Points 16 and 19 as depicted on Figure 93 are located at the primary fault in the area and discharged water <br />from the roof after being mined through. This discharge was observed to taper off and eventually cease <br />entirely from these locations. A decline in water levels was noted updip at Wadge Overburden wells <br />93M001 and 93M003 during approximately the same time frame. The depth to water in well 93M001 was <br />recorded at 37.5 feet in September 1995, 50.8 feet in May 1996, and 65.8 feet in September 1996. The <br />depth to water in well 93M003 was recorded at ] 19.0 feet in September 1995, 282.0 feet in May 1996, and <br />338.7 feet in September 1996. Development work through the fault th l OR (site 19) occurred during <br />October 1995, development through the fault in 9R (site 16) occurred during August 1995. Points 15 and <br />18 exhibited flow from the floor of the mine during the mine inflow survey. No structure was evident at <br />i:tdocummt~ahrV'oidel.ck~95ahrrsp. doc <br />