2011-02-28_PERMIT FILE - C1991078A ‎(4)‎

• Permit No: C1991078A
• IBM Index Class Name: Permit File
• Doc Date: 2/28/2011
• Section_Exhibit Name: 2.05 Operation and Reclamation Plan
• Media Type: D
• Archive: Yes

2.05.6(3) Protection of the Hydrological Balance
(a)(i) The surface water from precipitation events
caithin the disturbed areas will be coursed to sedimentation ponds
for s minimum of 24 hours detention. The water discharged from
these sedimentation ponds will meet the effluent standards for
discharge through the use of valved dewatering pipes that will be
opened after settlement of the suspended solids.
Surface water from the mining operation is
not expected to degrade the surface water systems in the area.
The only possible degradation would be of Naturita Creek between
Broad Canyon upstream and the San Miguel River downstream.
Surface water from the mining operation
should not degrade the quality of water in the San Miguel River.
Bruce Zander with the EPA performed a DFLOW analysis for the USGS
station on the San Miguel River at Naturita. The 30 day, 3 year
low flow was 20.2 cfs for the data period 1918 - 1981. The 1
day, 3 year low flow for the same period of record was 6.0 cfs.
In any case, if any run-off from the mine were to reach the San
Miguel River, the dilution factor would mitigate any effect the
mine water could have on the river. A 100 gpm flow from the mine
would have a 26.93 dilution factor using the 1 day, 3 year low
flow and the dilution factor would increase to 90.66 for the 30
day, 3 year low flow. The San Miguel River is not expected to
receive any run-off from the mine site. The 100 gpm flow was
used to demonstrate the order of magnitude of a dilution factor.
• The one aquifer within the permit area is
about 20 feet thick and lies 90 to 100 feet below the last mine-
able coal seam. Analysis of drilling logs indicate several
strata of impermeable shales between the aquifer and the lowest
coal seam to be mined, totaling approximately 20 feet in thick-
ness. This impervious stratum should eliminate any effects on
the aquifer from the mining operation.
The aquifer discharges at various springs
adjacent to the permit area. Since the mining operation is not
expected to impact the aquifer, then it should not impact the
area springs.
lii) As explained above, the mining operation is
not expected to adversely affect the ground water or surface
water systems within or adjacent to the permit area. The rights
of present users of the surface and ground water, if any, should
therefore not be affected.
• 2.05-33 May 1991