2011-07-21_PERMIT FILE - C1982056A ‎(2)‎

• Permit No: C1982056A
• IBM Index Class Name: Permit File
• Doc Date: 7/21/2011
• Section_Exhibit Name: 2.04 Environmental Resources
• Media Type: D
• Archive: Yes

SOUTHWEST MINING DISTRICT
The general information provided above can be applied to the Southwest Mining District. This area is located
• within the surface and ground water basins described above. Map 4, Proposed Hydrologic Area B- oundaries, has
been modified to reflect the permit revision.
EASTERN MINING DISTRICT
A strict application of these definitions to Twentymile Park results in the areas shown on Map 4, Proposed
Hydrologic Area Boundaries. The proposed permit area includes all lands to be disturbed by mining activities
over the life of the Eastern Mining District. The proposed adjacent area includes the Twentymile Park ground
water basin, including the downstream reaches of the perennial streams of Foidel Creek, Middle Creek, and
Trout Creek to the confluence with the Yampa River at Milner. The proposed general area includes the
Twentymile Park ground water basin and the watersheds of Fish Creek, Foidel Creek, Middle Creek, and Trout
Creek to the confluence with the Yampa River at Milner.
The general information provided previously can be applied to the Eastern Mining District. This area is located
within the surface and ground water basins described above. Map 4, Proposed Hydrologic Area Boundaries,
presents the area covered in this permit application.
The ground water inflow into the mine during the proposed longwall operation in the Eastern Mining District
was calculated with the application of an analytical method (Maximov, 1975). Results of these calculations are
presented in Exhibit 9A, Ground Water Inflow Into Mine, Eastern Mining District, Table 1 and Table 2. These
Maximov (1975) and developed for the calculation of ground water inflow into horizontal sections of an
underground mine was used for mine inflow calculation:
q = KMs (7c / at) 1 /2
• Where: q is water inflow per a longitudinal section of an underground mine (m3 /day)
K is hydraulic conductivity ( m/day)
M is hydrostatic head (m)
s is drawdown
a is coefficient of piezoconductivity (m2 /day)
a = T/S where T is transmissivity (m2 /day) and S is storativity
t is time of dewatering days
The total inflow per (longwall panel) section of the mine or level is then calculated from:
Q = q x 1
Where: 1 is length of dewatered section (m)
The total horizontal inflow per (longwall panel) section of the mine or level was calculated using hydraulic
conductivity ranging from 0.034 to 0.098 ft/day. The geometry of the mined area and time of dewatering are
based on mining plans. The analytical equation presented above was input into a simple spreadsheet computer
program (LOTUS 123) on an IBM computer. The results of the inflow calculations for the Eastern Mining
District are summarized and presented in Tables 3 and 4 of Exhibit 9A. The average inflow in one panel could
range from 65 to 230 gpm and the total inflow in the Eastern Mining District could range from 110 to 601 gpm.
The geology of the Eastern Mining District is similar to the previously permitted areas. A syncline axis,
oriented northwest- southeast is located in the central section of the mined area. The southeastern edge of the
.proposed mining is defined by a split in the Wadge Coal Seam. Additional exploration boreholes will be drilled
in this area to better define the coal seam composition.
MR 11-254 2.04 -10 06/28/11