2022-06-02_REPORT - C1981010

• Permit No: C1981010
• IBM Index Class Name: Report
• Doc Date: 6/2/2022
• Doc Name: Annual Hydrology Report Adequacy Review
• From: DRMS
• To: Trapper Mining Company
• Email Name: RAR
• Email Name: JLE
• Media Type: D
• Archive: No

Requirement Regulation Comment
Notes of monitoring frequency:
o Groundwater elevation data was not submitted for
wells GLEV-2, and GP-7 because these locations were
dry during all four quarters of 2021. Well P-5 was dry
during the 2nd and 31d quarters. GP-7 has been dry
since mid-2018,GLEV-2 has been dry since it was
first monitored in January 2015, and P-5 P-5 has
intermittent water present. Previously,P-5 goes dry
P. Sampling Table 4.8-13a during the latter part of the year. It should be noted
frequency of of CDRMS that between January 2005 and June 2010 only one
groundwater mining permit water level was recorded.
monitoring wells C-81-010 o P-5,GLEV-2, and GP-7 were not sampled for List B
and C sampling requirements. Sulfate is part of the
List B suite of analytes.
o Monitoring of 81-031A was re-initiated beginning the
last two quarters of 2020.Monitoring at this location
was stopped after June 2006. (It should be noted that
water level data was collected for this well and
presented in Table A-1 but no graph of historic and
present data was given.) Data from this well was used
in generating the Potentiometric Surface Map 2-3.
Q. Parameters to be Table 4.8-13 of
analyzed in CDRMS Adequate
groundwater mining permit
samples C-81-010
Six alluvial wells monitor Flume,Coyote,Deacon,Pyeatt and
Johnson alluviums(COY,GC3,CYA,GLEV2,P1 and J1
respectively). Well GP-9,Trapper's groundwater point of
compliance monitors the Third White Sandstone immediately
downgradient from Trapper's pits at a location where a leachate
plume can be expected to form,as explained in the PHC
(Section 4.8.3 of the permit and page 4-242).
The 2021 data from well GP-9 does not reflect any new
exceedances of the Basic Standards for Ground Water for a
domestic use classification based on the parameters analyzed,
and the results are consistent with historical results. (This
classification is for the Third White Sandstone in a Specified
R. Basic Standards CWQCC Area that extends outward from Trapper's northern permit
for Ground regulations boundary on the east half of the mine to the axis of the Big
Water 41.4 and 41.5 Bottom Syncline,a distance ranging between 1/2 and 3/4 mile
from the boundary.) There continues to be an exceedance of the
drinking water standard for Mn;however,Mn exceedances also
occurred in well GP-9 prior to mining in the area upgradient of
this well. Other groundwater quality factors(e.g.,concentrations
of TDS and sulfate)continue to remain within historical
sampling ranges and indicate that coal spoil leachate probably
has not reached GP-9.
Flume Gulch alluvium could also be contaminated by coal spoil
leachate. The Coy well is the groundwater point of compliance
for the Flume Gulch alluvium,as explained on page 4-242 of the
permit application. Sampling data from 2021 indicates no
exceedances of the Basic Standards for Ground Water for the
Page 3