_GENERAL DOCUMENTS - C1981017 ‎(262)‎

• Permit No: C1981017
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Name: Bid Documents ‎(IMP)‎ Backfilling and Grading Plan for Preparation Plant Area
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

-38-
� t
he three underground mines along the Roaring Fork River may impact
round water quantity by one or more of the following:
- induced inflows into the mines through faults and fractures
wnich provide communication between the mine and overlying and
underlying aquifers and surface waters;
- dewatering of the coal , roof and floor with the advance of
mining; and
- subsidence-induced flows into the mines.
Faults and fractures wnich cut the bedrock strata produce a localized
increase in porosity within the strata. If the faults and fractures do
not become sealed by clays, they may become conduits for the flog: of
ground and surface water. When encountered within the mine, faults and
fractures will dewater. The amount of water flowing into the mine from
��Ntractures,
hese sources depends on porosity and permeability of faults or
v and on the open vertical connection within the faults and
ractures between the coal seam and sources of ground or surface water.
�,Rv [Fault and fracture controlled inflows have been noted and mapped in the
nowmass Coal Company North Thompson Creek Nines application (Figure
.6. 1-5 to -7) , in the U.S. Steel Corporation Somerset Mine application
Exhibit E8-3366) , the Western Slope Carbon Hawk' s ;Jest Mine permit
application (Exhibit 2.04. 7(1 ) or 'W-IOU6) , the Blue Ribbon Coal Company,
Blue Ribbon Mine application (Exhibit T) and the Colorado Westmoreland,
Orchard Valley Mine (Revision Submittal of November 18, 1982) . The Mt.
Gunnison No. 1 Mine has encountered only minor inflows from fractures in
the No. 1 portal .
� From field observations made by CMLRD hydrologists in the mines in the
adjacent Somerset Coal Field and from information contained in their
j� respective per-nit applications, water was noted to seep from the coal ,
roof, and floor upon advance of mining in the "B" and "C" seams of the
Somerset Mine, the "D" seam of the Orchard Valley Mine, the "E" seam of
the Hawk' s Nest and Blue Riobon mines, and "F" seam of the Mt. Gunnison
No. 1 �•1ine. These sources of mine inflows dry up one to two weeks after
vl mining an area. The minor amount of water resulting from dewatering of
the coal , roof, and floor indicates that the coals and the overlying and
underlying strata in the iNesaverae Group have very low permeaoilities.
Thus, these strata store and transmit very little water and are not
considered aquifers. TheraforP. the �mnArt� of ri-waterinn +'hE coals and
the strata immediately aboveano below the coals within
Group q111 nave an insignificant im ct on the hydrologic a _ ,also,
or inflow resijlting from dewatering strata indicated
that these strata will not transmit significant quantities of eater which
Mould result in depletion of surface ,eater sources.