2019-01-08_REPORT - C1994082

• Permit No: C1994082
• IBM Index Class Name: Report
• Doc Date: 1/8/2019
• Doc Name: Annual Hydrology Report Adequacy Review
• From: DRMS
• To: Peabody Energy, LLC
• Annual Report Year: 2017
• Permit Index Doc Type: Hydrology Report
• Email Name: RAR
• Media Type: D
• Archive: No

Peabody Energy, LLC
Page 5
2018

Requirement Requirement citation Comment
18. Basic Standards for
Ground Water
CWQCC regulations 41.4
and 41.5
The Yoast Mine did not generate significant amount of
leachates in 2017. One groundwater well exceeded the
manganese standard (0.02ug/l) in 2017.
19. Restoration of ground
water recharge to
approximate pre-mining rate
CDRMS regulation
4.05.12(3)
For the 2017 water year, it appears that water levels at
all wells fell within their historic ranges, with the
exception of well YOV30 and YW30. YW30 displayed
its highest level ever during the 2017 water year with a
value of 136.12 feet while well YOV30 exhibited a
historic low at 133.64 feet. All alluvial wells displayed
seasonal water level fluctuations in response to periods
of precipitation recharge.
20. Prevention of adverse
impacts to ground water
systems outside permit area
CDRMS regulation
4.05.11(1)
Compliance with the Basic Standards for ground
water, as in item 10, indicates the permittee is
preventing adverse impacts to ground water quality
outside the permit area. Note: no water quality data was
located for Point of Compliance Well SGAL70.
Note: Water level reports as presented in Appendix B
of the AHR Hydrology Report did not indicate average
water levels.

All alluvial wells showed seasonal water level
fluctuations in response to periods of precipitation
Or, lack thereof. Overburden and coal well water
levels are fluctuating in response to the precipitation
recharge and ground water flow from the reclaimed
mine pits. Please see adequacy question # 4 above
concerning the data provided.
21. Prevention of impacts to
ground water that adversely
impact post-mining land use
CDRMS regulation
4.05.11(2)
No material damage has occurred, as discussed in
item 20, above.
22. Minimize disturbance to
hydrologic balance within
and adjacent to the permit
area
CDRMS regulation
4.05.1(1)
The disturbance to the hydrologic balance within and
adjacent to the permit area caused by mining
and reclamation at the Yoast Mine is the minimum
that can be expected from a reclaimed surface mine at
this location. The operators’ use of best management
practices indicates minimization of disturbance to the
hydrologic balance.
23. Prevention of material
damage to the hydrologic
balance outside the permit
area
CDRMS regulation
4.05.1(1)
Surface water –A prediction was made that
Increases in TDS would be observed at various stream
sites during the irrigation season (June-September).
Average TDS at all four sites was lower than predicted
for the 2017 water year.

Ground water – In TAB 17 of the PAP, predictions
were made as to the expected TDS increases to be
observed at various monitoring wells. Predicted TDS
values were exceeded at 4 of the 7 sites with the peak
values occurring as far back as 2007 and as recently as
2014. Although the 4 sites exceeded TDS predictions,
the alluvial wells did not exceed the TDS Point of