2011-09-26_PERMIT FILE - C1981012 ‎(24)‎

• Permit No: C1981012
• IBM Index Class Name: Permit File
• Doc Date: 9/26/2011
• Section_Exhibit Name: EXHIBIT 08 HYDROLOGY AND GEOLOGY INFORMATION
• Media Type: D
• Archive: No

i
16
l formation are summarized in Table 1. •
C.
The permeabilities listed in Table 1 are intrinsic oermeabilities ex-
pressed in milli-darcys. The relationship bet~.aeen hydraulic conductivity,
K, (also often called permeability) in centimeters per second and intrinisic
permeability, k, in milli-darcys is X = 3.952 x 10-~ k for water at 63° F.

i The magnitudes of permeability and porosity listed in Table 1 are of less
' importance to the present discussion than is the variation. There is no
apparent trend in permeability with respect to location of the wells. In
! other words, there is no evidence in these data that the permeability of
the overburden sandstones at the Maxwell is significantly different from
that at the Allen. Furthermore, the permeabilities of the sandstones of
the Raton formation fall within a surprisingly narrow range of 0.12-1.65
milli-darcy, with the large majority of values clustered around the mean.
This observation lends additional credence to the conclusion that the
channel sandstones in the Raton formation in the vicinity of the Allen and
Maxwell Mines are quite uniform with respect to permeability, even though
their occurrence, geometry, and lateral continuity are very heterogeneous. _
•
As indicated previously, the location and geometry of the Purgatoire
River does not appear to be related to the occurrence of fractures, joint-
fng, or faulting. Therefore, the probability of occurrence of fractures
connecting the Maxwell coal seam with the river and associated alluvium
is~no greater at the i4axwell Mine than at the Allen Mine. This, coupled
with the conclusion that the vertical permeabilities of the most permeable
overburden strata are not significantly different at the two mines, leads
to the expectation that downward flow from the valley induced by mining
beneath the valley at the Maxwell will not be significantly different from
that experienced at the Allen. While the contribution of downward flow
from the valley to the total inflow at the Allen cannot be determined, mine
personnel did not observe any noticeable increase in mine inflow as several
headings were driven beneath the valley at various times during the life of
the mine. Using the permeabilities listed in Table 1, estimates of the
potential magnitude of vertical inflow from the valley are made subsequently
in this report.
The above discussion has significance only with respect to the •