PERMFILE51632

• Permit No: C1982056A
• IBM Index Class Name: Permit File
• Doc Date: 9/13/2005
• Section_Exhibit Name: 2.04 Environmental Resources
• Media Type: D
• Archive: Yes

Roof, floor and coal samples were obtained from holes 97006 and 97007. The data is presented on Tables 20D,
20E and 20F.
Middle Creek Mine Data TCC reviewed historic records and personnel working at the mine to determine the
extent of mine inflow into the short-lived Middle Creek Mine. The information obtained from this process
indicates that the inflow into the mine was approximately 60 gallons per minute. This information was obtained
from a 1981 memorandum from Mike Ludlow to J. Weston. In addition to the mine flow rates, there was additional
information addressing dewatering wells that had been installed at the site. The memorandum indicates that the
wells produced anywhere from O.S to 120 gallons perm minute. Therefore, it appears that the maximum inflow
into the mine in this area was 60 gallons per minute, while the maximum pumping rate for a dewatering well was
120 gallons per minute. The outline of the mine is shown on Map S. As is noted, the mine only advanced
approximately 900 feet before the decision was made to abandon the project.
Based on the historic record, it appears the inflow came into the mine from the roof strata. The Middle Creek mine
was under a low overburden height of 300-650 feet and the overburden was highly fractured from the previous
surface mine operations at the highwall and its location in a fault zone. It was always the intent of the Middle
Creek mine plan to cross the fault located in Section 12, TSN, R86W where mining conditions on the west side of
that fault were anticipated to be much improved for both groundwater inflow and dip of coal seam. It is known
that this water came into the mine from the Wadge overburden by means of roof bolting drill holes, the mine
portals were aligned close to parallel with the local and regional faults, cleats, joints, and fractures.
Twentymile has drilled exploration holes (2) in Section 14, TSN, R86W with no evidence of significant
groundwater flows. Twentymile has also mined entries in the Wadge coal seam and currently maintains ventilation
through the East Mine District bleeder shafts in Section 14, TSN, R86W. Again there is no groundwater water inflow
in these mined out areas. Based on these observations and the experiences in the Wadge coal seam for both the
western and eastern mining districts, no major groundwater inflow is anticipated for the development mining proposed
for the Wadge Coal Seam in Sections 11 and 14, TSN, R86W. The proposed development will be mining in areas of a
minimum 700 feet of overburden which has not led to groundwater inflow in comparable areas of the western and
eastem mining districts. The 6 Right Outby secfion of the East Mine District was developed in an area of less than
500 feet of overburden where groundwater inflow was experienced. If groundwater inflow were to be encountered in
the development mining of Sections 11 and 14, TSN, R86W, Twentymile Coal would use local sumps driven into the
floor of the gateroad section to collect the water and pump it downdip to the Northeast Mains section whereby it
would then be collected in the existing sump and pumped through the present mine dewatering system.
NMD (Panels 17 Right through 21 Right) (PR 03-06)
The general geology and hydrology of the remaining NMD segment has been described in the previous No. 4 and No.
S permit revisions. Exploration drilling in 2002 was used to establish mining limits related to steep grades near the
eastern flank of the Tow Creek Anticline. Combined results of the 1999 and 2002 surface 2D seismic exploration
further helped to define the eastern and northern regional fault trends which control the mining boundary for the
remaining NMD district longwall panels. Revised steep grade and fault limits are displayed on the Surface Geology
and Wadge Seam Structure maps (Maps S and 6).
PR 03-06 2.04-16.3 03/02/04