Clean Water Act discharge permit · NPDES MT0026808
STILLWATER MINING CO EAST BOULDER MINE, Big Timber, MT: NPDES MT0026808 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 24Pollutants under a numeric limit
- 4Pollutants with an effluent exceedance
STILLWATER MINING CO EAST BOULDER MINE, held by STILLWATER MINING COMPANY, holds NPDES permit MT0026808, which discharges to East Boulder River. EPA’s file records it issued September 28, 2015 and expiring October 31, 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 CO EAST BOULDER MINE |
|---|---|
| Permittee as filed | STILLWATER MINING COMPANY |
| NPDES ID | MT0026808 |
| 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 | September 28, 2015 |
| Expiration date | October 31, 2020 |
| Address | Big Timber, MT 59011 |
| Receiving water | EAST BOULDER RIVER |
| Subwatershed | Last Chance Gulch (HUC 100301011309) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 29Pollutants on file
- 24Under a numeric limit
- 21With 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 |
|---|---|---|---|---|---|
| Nitrogen, inorganic total | 18 | 129 | 74 | September 30, 2015 | 505% over the limit |
| Lead, total recoverable | 5 | 6 | 3 | November 30, 2023 | 127% over the limit |
| Mercury, total recoverable | 4 | 2 | 2 | January 31, 2026 | 20% over the limit |
| Nitrogen, total [as N] | 6 | 19 | 1 | April 30, 2007 | 45% over the limit |
| Nitrite + Nitrate total [as N] | 20 | 39 | 0 | ||
| Nitrogen, ammonia total [as N] | 18 | 39 | 0 | ||
| Flow rate | 5 | 24 | 0 | ||
| pH | 20 | 17 | 0 | ||
| Water level at sample collection time | 7 | 15 | 0 | ||
| Specific conductance | 14 | 9 | 0 | ||
| Nitrogen, Kjeldahl, total [as N] | 4 | 8 | 0 | ||
| Sulfate, total [as SO4] | 0 | 7 | 0 | ||
| Phosphate, ortho [as P] | 0 | 7 | 0 | ||
| Solids, total dissolved | 0 | 7 | 0 | ||
| Temperature, water deg. fahrenheit | 7 | 6 | 0 | ||
| Phosphorus, total [as P] | 2 | 6 | 0 | ||
| Iron, total recoverable | 5 | 3 | 0 | ||
| Copper, total recoverable | 5 | 3 | 0 | ||
| Nickel, total recoverable | 4 | 2 | 0 | ||
| Pass/Fail Static Renewal 48Hr Acute Ceriodaphnia dubia | 0 | 2 | 0 | ||
| Pass/Fail Static Renewal 96Hr Acute Pimephales Promelas | 0 | 2 | 0 | ||
| Zinc, total recoverable | 4 | 0 | 0 | ||
| Cadmium, total recoverable | 4 | 0 | 0 | ||
| Chromium, total recoverable | 4 | 0 | 0 | ||
| Solids, total suspended | 3 | 0 | 0 | ||
| BOD, 5-day, 20 deg. C | 1 | 0 | 0 | ||
| Report due [yrmoda] | 1 | 0 | 0 | ||
| LF Pass/Fail Statre 7Day Chronic Pimephales | 1 | 0 | 0 | ||
| Pass/Fail Static Renewal 7 Day Chronic Ceriodaphnia dubia | 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
- 0Single-event violations
EPA’s single-event violation file, as loaded, holds no violation for NPDES MT0026808.
Velarion’s copy of EPA’s ICIS-NPDES files does not 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.
Watch this permit
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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 MT0026808 there.
Nearby on the register
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- Every permit record in Big Timber, A to Z
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- Every permit record in Montana, A to Z
Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.