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

Review of 2020 Annual Hydrology Report
Mine: Trapper Mine Date of review: 2 June 2021
Permit No.: C1981010 DRMS reviewer: P.Lennberg Ground Water
R.Reilley Surface Water
Report Year: 2020 Submitted by: DRMS
Date received by Division: March 15,2021
Requirement Regulation Comment
A. Filing frequency CDRMS
of hydrology regulation Annual Filing.
report 4.05.13(4)(c)
March 15
according to
B. Timely filing of Sections The report was filed on March 15,2021.
hydrology report 4.8.5.1 and
4.8.5.2 permit
C-81-010
C. Filing frequency
of NPDES NPDES permit
Discharge CO-0032115 Filing frequency was met.
Monitoring
Reports
D. Timely filing of
Discharge NPDES permit Filing of reports was timely
Monitoring CO-0032115
Reports
E. NPDES NPDES permit Trapper monitors 16 drainage systems. The Trapper Mine
discharge CO-0032115 discharged from ponds 001,002, 011,and 020 in 2020. No
limitations compliance limits were exceeded in 2020.
F. Basic Standards CWQCC See section G below: Instream Numeric Standards.
for Surface Water Regulation 31
Trapper's discharges from several NPDES outfalls drain to
Segment 3b of the Lowe r Yampa River. Trapper's
NPDES discharge limitations are based on constituents in
G. Instream CWQCC Trapper's effluent likely to cause an exceedance of
Numeric Regulations 31 Segment 3b's numeric standards. Discharges in 2020
Standards and 37 appeared to comply with discharge limitations set as per
the NPDES permit. It is reasonable to conclude that
Trapper's discharges did not violate Segment 3b's
instream numeric standards.
H. Antidegradation CWCC Trapper is not subject to the Antidegradation Rule because the
Rule for Surface regulations receiving waters(Segment 3b of Lower Yampa River)are
Water 3.1.9(2) and designated as use protected.
3.3.0.
L Interim Narrative CWQCC
Standard for regulation Reviewed
Ground Water 41.5.C.6
J. Sampling Table 4.8-11 of
frequency at CDRMS Trapper conducted surface monitoring in accordance with the
surface water mining permit approved monitoring plan and frequency.
monitoring sites C-81-010
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