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Roof, floor and coal samples were obtained from holes 97006 and 97007. The data is presented on Tables 20D, <br />• 20E and 20F. <br />Middle Creek Mine Data TCC reviewed historic records and personnel working at the mine to determine the <br />extent of mine inflow into the short-lived Middle Creek Mine. The information obtained from this process <br />indicates that the inflow into the mine was approximately 60 gallons per minute. This information was obtained <br />from a 1981 memorandum from Mike Ludlow to J. Weston. In addition to the mine flow rates, there was additional <br />information addressing dewatering wells that had been installed at the site. The memorandum indicates that the <br />wells produced anywhere from 0.5 to 120 gallons perm minute. Therefore, it appears that the maximum inflow into <br />the mine in this area was 60 gallons per minute, while the maximum pumping rate for a dewatering well was 120 <br />gallons per minute. The outline of the mine is shown on Map 5. As is noted, the mine only advanced approximately <br />900 feet before the decision was made to abandon the project. <br />Based on the historic record, it appears the inflow came into the mine from the roof strata. The Middle Creek mine <br />was under a low overburden height of 300-650 feet and the overburden was highly fractured from the previous <br />surface mine operations at the highwall and its location in a fault zone. ]t was always the intent of the Middle <br />Creek mine plan to cross the fault located in Section 12, TSN, R86W where mining conditions on the west side of <br />that fault were anticipated to be much improved for both groundwater inflow and dip of coal seam. It is known that <br />this water came into the mine from the Wadge overburden by means of roof bolting drill holes, the mine portals <br />were aligned close to parallel with the local and regional faults, cleats, joints, and fractures. <br />Twentymile has drilled exploration holes (2) in Section 14, TSN, R86W with no evidence of significant groundwater <br />flows. Twentymile has also mined entries in the Wadge coal seam and currently maintains ventilation through the <br />East Mine District bleeder shafts in Section 14, TSN, R86W. Again there is no groundwater water inflow in these <br />mined out areas. Based on these observations and the experiences in the Wadge coal seam for both the western and <br />eastern mining districts, no major groundwater inflow is anticipated for the development mining proposed for the <br />• Wadge Coal Seam in Sections 11 and 14, TSN, R86W. The proposed development will be mining in areas of a <br />minimum 700 feet of overburden which has not led to groundwater inflow in comparable areas of the wes>rm and <br />eastem mining districts. The 6 Right Outby section of the East Mine District was developed in an area of less than <br />500 feet of overburden where groundwater inflow was experienced. Tf groundwater inflow were to be encountered in <br />the development mining of Sections I 1 and 14, TSN, R86W, Twentymile Coal would use local sumps driven into the <br />floor of the gateroad section to collect the water and pump it downdip to the Northeast Mains section whereby it <br />would then be collected in the existing sump and pumped through the present mine dewatering system. <br />• <br />PR 99-OS 2,04-16.3 05/26/00 <br />