2012-01-26_PERMIT FILE - C1981018A

• Permit No: C1981018A
• IBM Index Class Name: Permit File
• Doc Date: 1/26/2012
• Section_Exhibit Name: Section II.C Hydrology
• Media Type: D
• Archive: Yes

• extensive sediment control structures and through longwall subsidence troughs acting as sediment
traps. As noted in the baseline studies, the surface water quality parameters (TDS, Fe, pH, Mn)
are primarily related to the amount of suspended solids in the flow and the location of the source of
the flow. This has been found the case during the monitoring program. The groundwater
encountered in the mine thus far has been about the quality that was expected based on the
baseline data. If it is assumed that all of the groundwater entering the mine as seep water (43.75
GPM as of October 1992) is produced from the broken ground in the longwall panels (about 687
acres) then each acre of broken ground is producing approximately 0.06 gallons per minute. The
low-yielding strata (aquatards) are what was predicted from the baseline data. The groundwater
quality has been found relatively poor as predicted from the baseline data. The low permeability of
the rock has kept the groundwater in contact with rock for a long time and results in increased
dissolved constituents.
The filling of Kenney Reservoir actually inundated some Deserado facilities and effected the quality
of water in the alluvium. The ground water monitoring program was affected also as five of the six
alluvial monitoring wells were rendered useless. The reservoir, by maintaining a relatively stable
water level in the alluvium compared to the previous seasonally fluctuating water level appears to
have helped to increase the Qal-5 water level. A general increase in TDS as new alluvium was
saturated followed by a gradual decrease has also been noted. This can be seen in the
hydrographs of QAL-5 (the remaining alluvial monitoring well) and in the TDS measurements taken
before and after the filling of the reservoir in the fall of 1984.
• The decline in piezometric levels in bedrock zones "upper sandstone facies, siltstone/coal facies,
and "lower sandstone facies" was anticipated as probable impacts as the result of underground
mining activities. As projected, these impacts are localized and seem to continue in the proximity of
the mined area, but seem to improve once mining activity has ceased in the proximity of the
affected monitoring wells.
As projected, subsidence in Red Wash initially resulted in water ponding in the stream bottom. The
high content of silt and clay carried by Red Wash rapidly filled the pond. The silt and clay layers
have sealed any cracks that formed in the alluvium as the result of subsidence. Water continues to
flow in the surface channel at Red Wash while piezometric levels in the basal alluvial gravel have
dropped indicating that the basal alluvium is not recharged by surface flow infltration. The water
level has remained stable since the initial drop in the level.
Water ponding in Red Wash as the result of subsidence over longwall panel No. 1 acted as a
stilling basin for deposition of clays and silts being carried down Red Wash. The significance of
this impact is beneficial as the sediment load to the White River was reduced.
In summary, the predictions based on the hydrologic baseline work have been proven generally
accurate by the hydrologic monitoring program.
Midterm Review 2002 (Rev. 8/02) II.C-86