GENERAL52614

• Permit No: C1981044
• IBM Index Class Name: General Documents
• Doc Date: 4/24/1987
• Doc Name: Proposed Decision & Findings of Compliance for PR1
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

approaches 50 percent of the total 631 gpm estimated in 1985 as average inflow
for the entire No. 5 Mine. The flow from these faults has remained -
essentially the same since 1983. The remainder of mine inflow results from
more general sources, ie. roof, floor, pillars and coal faces located both in
the western and eastern portions of the mine. The present area of activity in
the No. 5 Mine, located in the southeast part of the permit area, tends to be
the driest part of the operation.
Due to the inflow of water into the workings of the Eagle No. 5 Ftirte, the
quantity of ground water in adjacent aquifers can be impacted. The Trout -
Creek Sandstone lies some 320 to 360 feet below the "F" seam in which the
Eagle No, 5 is located. The Eagle No. 6 Mine, to be developed in the "E" seam
will be some 40 to 100 feet stratigraphically closer to the Trout Creek
sandstone. The Trout Creek Sandstone is under artesian conditions in most of
the permit area where it has supplied water for industrial and domestic
purposes. Regular monitoring of the Trout Creek aquifer, however, was not
conducted until rather recently when the growing body of evidence indicated
that the Trout Creek was dewatering into the No. 5 mine by way of the faults
encountered in the western mine workings.
Empire Energy Corporation produces water for its mining operations from two
wells in the Trout Creek aquifer, These wells, the No. 5 and 5A, are located
near the Eagle No, 5 Mine portal. Subsequent to encountering the
fault-associated inflows in the western mine workings, Empire Energy
Corporation reports the No. 5 Mine well experienced a decline in static head
which reduced it from a flowing to non-flowing artesian condition, The amount
of this past decline cannot be quantified from the existing records. Any
future impacts, however, will be documented since both the No. 5 Mine well and
the Okie Plaza well, which also produces from the Trout Creek sandstone, will
be included in the future hydrologic monitoring plan. A third Trout Creek
well, the No, 5A Mine supplemental well, is located within a few feet of the
No. 5 Mine well, and will not be monitored as part of the plan. No
significant additional impacts on the quantity of water in the Trout Creek
sandstone are likely to result from proposed mining of the "E" and "F" seams
during the first five permit years, Both the remainder of the work in the
Eagle No. 5 Mine and the Eagle No. 6 mining will be conducted in the eastern
and southeastern portions of the permit area where current general inflow into
the existing No. 5 Mine workings is minimal, where both the No. 5 and No. 6
Mines are separated from the Trout Creek aquifer by significant thicknesses of
sedimentary rock, and where no evidence of faulting has been obtained,
The Middle sandstone lies approximately 125 feet to 150 feet above the "F"
seam and the Eagle No, 5 mining, At one time, the Middle sandstone was
believed to be the primary source of the fault associated water inflow
encountered in the western mine workings because of the relatively abrupt
declines in water levels recorded by Middle sandstone monitoring Wells TR-4,
TR-7A, and 81-Oi shortly after the fault zone was reached. As evidence
accumulated, however, that the Trout Creek sandstone is the more likely source
of the water and since water levels in the Middle sandstone have risen, it is
now argued that the earlier water level declines in the Middle sandstone were
simply climatic in orgin, related to drier years and periods of low recharge
of the aquifer. Whatever was responsible for those abrupt declines, the
impact on the quantity of water in the Middle sandstone is diminishing at this
time. Whether this lessening of impact will continue in the future as
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