2021-06-02_REPORT - C1981010

• Permit No: C1981010
• IBM Index Class Name: Report
• Doc Date: 6/2/2021
• Doc Name: Annual Hydrology Report Adequacy Review
• From: DRMS
• To: Trapper Mining Inc
• Annual Report Year: 2020
• Permit Index Doc Type: Hydrology Report
• Email Name: RAR
• Email Name: JLE
• Media Type: D
• Archive: No

Requirement Regulation Comment
Trapper added four new groundwater monitoring wells,
located in the northwest corner of the permit area and
completed in the 31d,2nd and 1st White Sandstone formations
(CY3,CY2,CY1 and CYA,respectively). Monitoring of well
81-03A recommenced in 2020.
Notes of monitoring frequency:
o Groundwater elevation data was not submitted for
wells P-5,GLEV-2, and GP-7 because these locations
were dry during all four quarters of 2020. GP-7 has
been dry since mid-2018,GLEV-2 has been dry since
it was first monitored in January 2015, and P-5 has
been dry since the last two quarters of 2019.
Previously,P-5 goes dry during the latter part of the
year. It should be noted that between January 2005
P. Sampling Table 4.8-13a and June 2010 only one water level was recorded.
frequency of of CDRMS o P-5,GLEV-2, and GP-7 were not sampled for List B
groundwater mining permit and C sampling requirements. Sulfate is part of the
monitoring wells C-81-010 List B suite of analytes.
o Monitoring began at wells CY-A, 1,2 and 3 starting
the last two quarters of 2020.
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. The
data collected from this well should be included with
the graph in Figure A-12.Finally Table 4.8-13a,
updated with TR126,does not indicate that water
levels will be collected quarterly,this error should be
corrected to clearly indicate water levels will be
collected quarterly.)
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 Jl
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).
R. Basic Standards CWQCC
regulations The 2020 data from well GP-9 does not reflect any new
for Ground Water 41.4 and 41.5 exceedances of the Basic Standards for Ground Water for a
domestic use classification based on the parameters analyzed.
(This classification is for the Third White Sandstone in a
Specified Area that extends outward from Trapper's northern
permit boundary on the east half of the mine to the axis of the
Big 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
Page 3