Clean Water Act discharge permit · NPDES MT0024716
STILLWATER MINING COMPANY, Nye, MT: NPDES MT0024716 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 26Pollutants under a numeric limit
- 4Pollutants with an effluent exceedance
STILLWATER MINING COMPANY holds NPDES permit MT0024716, which discharges to Stillwater River. EPA’s file records it issued October 30, 2015 and expiring November 30, 2020. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 15, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | STILLWATER MINING COMPANY |
|---|---|
| Permittee as filed | STILLWATER MINING COMPANY |
| NPDES ID | MT0024716 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | October 30, 2015 |
| Expiration date | November 30, 2020 |
| Address | Nye, MT 59061 |
| Receiving water | STILLWATER RIVER |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Stillwater River-Mountain View Creek (HUC 100700050204) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 32Pollutants on file
- 26Under a numeric limit
- 30With a violation of any kind
- 4With an effluent exceedance
An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Zinc, total recoverable | 26 | 113 | 8 | May 31, 2024 | 77% over the limit |
| Lead, total recoverable | 26 | 110 | 8 | December 31, 2025 | 50% over the limit |
| pH | 20 | 110 | 4 | June 30, 2016 | |
| Copper, total recoverable | 26 | 107 | 4 | December 31, 2025 | 177% over the limit |
| Nitrogen, total [as N] | 47 | 258 | 0 | ||
| Nitrogen, ammonia total [as N] | 26 | 144 | 0 | ||
| Nitrogen, Kjeldahl, total [as N] | 20 | 137 | 0 | ||
| Nitrite + Nitrate total [as N] | 26 | 134 | 0 | ||
| Phosphorus, total [as P] | 20 | 120 | 0 | ||
| Cadmium, total recoverable | 26 | 109 | 0 | ||
| Mercury, total recoverable | 26 | 108 | 0 | ||
| Silver total recoverable | 20 | 106 | 0 | ||
| Cyanide, total [as CN] | 20 | 105 | 0 | ||
| Nickel, total recoverable | 20 | 100 | 0 | ||
| Aluminum, dissolved [as Al] | 24 | 98 | 0 | ||
| Chromium, total recoverable | 20 | 97 | 0 | ||
| Iron, total recoverable | 20 | 95 | 0 | ||
| Flow rate | 18 | 85 | 0 | ||
| Flow rate | 0 | 25 | 0 | ||
| Phosphate, ortho [as P] | 0 | 23 | 0 | ||
| Hardness, total [as CaCO3] | 2 | 8 | 0 | ||
| Aluminum, total recoverable | 2 | 6 | 0 | ||
| Specific conductance | 0 | 5 | 0 | ||
| Solids, total dissolved- 180 deg. C | 0 | 5 | 0 | ||
| Solids, total suspended | 2 | 4 | 0 | ||
| Oil & Grease | 2 | 4 | 0 | ||
| Nitrogen, inorganic total | 2 | 3 | 0 | ||
| Arsenic, total recoverable | 0 | 3 | 0 | ||
| Manganese, total recoverable | 0 | 3 | 0 | ||
| Pass/Fail Static Renewal 48Hr Acute Ceriodaphnia dubia | 1 | 1 | 0 | ||
| Report due [yrmoda] | 2 | 0 | 0 | ||
| Pass/Fail Static 96 Hr Acute Pimephales Promelas | 1 | 0 | 0 |
Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.
Inspections, violations and enforcement
- 1Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| August 4, 2022 | Reporting Violations - Improper/ Incorrect Reporting | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not yet include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.
Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.
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EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID MT0024716 there.
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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.