PLATORO MINE FACILITY
NPDES ID: CO0038954
E — SNC: Effluent violation (monthly average limit)
The facility discharged more of a pollutant than its permit allows, based on a monthly average.
This quarter: 7 effluent violations.
Violations
June 30, 2026
Iron, total recoverable
15% over limit
Discharged 1.93350009 mg/L against a permitted limit of 1.68100008 mg/L (ROLL AVG)
DMR, Limited - Numeric Violation
Arsenic, total recoverable
421% over limit
Discharged 0.23237001 mg/L against a permitted limit of 0.0446 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Manganese, dissolved [as Mn]
3% over limit
Discharged 0.47250002 mg/L against a permitted limit of 0.45800002 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
May 31, 2026
Arsenic, total recoverable
96% over limit
Discharged 0.08725 mg/L against a permitted limit of 0.0446 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Manganese, dissolved [as Mn]
39% over limit
Discharged 0.63830003 mg/L against a permitted limit of 0.45800002 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
April 30, 2026
Manganese, dissolved [as Mn]
712% over limit
Discharged 3.71955018 mg/L against a permitted limit of 0.45800002 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Arsenic, total recoverable
277% over limit
Discharged 0.16800001 mg/L against a permitted limit of 0.0446 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
June 30, 2025
Flow, in conduit or thru treatment plant
113% over limit
Discharged 0.614 MGD against a permitted limit of 0.288 MGD (30DA AVG)
DMR, Limited - Numeric Violation
Manganese, dissolved [as Mn]
158% over limit
Discharged 1.18300006 mg/L against a permitted limit of 0.45800002 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
May 31, 2025
Flow, in conduit or thru treatment plant
17% over limit
Discharged 0.336 MGD against a permitted limit of 0.288 MGD (30DA AVG)
DMR, Limited - Numeric Violation
Silver, potentially dissolved
138% over limit
Discharged 0.0001 mg/L against a permitted limit of 0.000042 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Manganese, dissolved [as Mn]
100% over limit
Discharged 0.91800004 mg/L against a permitted limit of 0.45800002 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Static Renewal 7 Day Chronic Pimephales promelas
0% over limit
Discharged 0 toxic against a permitted limit of 100 toxic (MN VALUE)
DMR, Limited - Overdue
Static Renewal 7 Day Chronic Pimephales promelas
0% over limit
Discharged 0 toxic against a permitted limit of 0 toxic (SINGSAMP)
DMR, Monitor Only - Overdue
Static Renewal 7 Day Chronic Ceriodaphnia dubia
0% over limit
Discharged 0 toxic against a permitted limit of 0 toxic (SINGSAMP)
DMR, Monitor Only - Overdue
Static Renewal 7 Day Chronic Ceriodaphnia dubia
0% over limit
Discharged 0 toxic against a permitted limit of 100 toxic (MN VALUE)
DMR, Limited - Overdue
Static Renewal 7 Day Chronic Ceriodaphnia dubia
0% over limit
Discharged 0 toxic against a permitted limit of 0 toxic (MN VALUE)
DMR, Monitor Only - Overdue
Static Renewal 7 Day Chronic Pimephales promelas
0% over limit
Discharged 0 toxic against a permitted limit of 0 toxic (MN VALUE)
DMR, Monitor Only - Overdue
First flagged
April 14, 2026 (4 months ago)
Last confirmed
August 16, 2026 (2 hours ago)