Clean Water Act discharge permit · NPDES MTR000503
STILLWATER MINING COMPANY, Big Timber, MT: NPDES MTR000503 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 15Pollutants under a numeric limit
- 0Pollutants with an effluent exceedance
STILLWATER MINING COMPANY holds NPDES permit MTR000503, which discharges to East Boulder River. EPA’s file records it issued May 16, 2018 and expiring January 31, 2023. The status and dates are as EPA’s permit file stood when Velarion loaded it (October 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
What the register holds for STILLWATER MINING COMPANY: its NPDES ID, its permit type and status, its dates, its address in Big Timber, Montana, its receiving water, and 15 pollutants under a numeric limit. EPA’s effluent violation file and its single-event violation file hold no violation for NPDES MTR000503.
Identity
| Facility as filed | STILLWATER MINING COMPANY |
|---|---|
| Permittee as filed | STILLWATER MINING COMPANY |
| NPDES ID | MTR000503 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Coverage under a general permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Program | Industrial stormwater |
| Issued | May 16, 2018 |
| Expiration date | January 31, 2023 |
| Address | Big Timber, MT 59011 |
| Receiving water | EAST BOULDER RIVER |
| Subwatershed | Lower East Boulder River (HUC 100700020701) |
| SIC | 1099 – Metal Ores |
| Other EPA IDs (FRS) | RCRA handler MTD981552292; ICIS-AIR source MT0000003009500001 |
Cited to the EPA ICIS-NPDES permit file (ECHO download) and EPA’s NAICS/SIC and component files, the same download; cross-program IDs from EPA’s FRS facility-registry crosswalk.
Effluent limits and exceedances
- 15Pollutants on file
- 15Under a numeric limit
- 0With a violation of any kind
- 0With 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 |
|---|---|---|---|---|---|
| pH | 16 | 0 | 0 | ||
| Solids, total suspended | 8 | 0 | 0 | ||
| Hardness, total [as CaCO3] | 8 | 0 | 0 | ||
| Arsenic, total [as As] | 8 | 0 | 0 | ||
| Beryllium, total [as Be] | 8 | 0 | 0 | ||
| Cadmium, total [as Cd] | 8 | 0 | 0 | ||
| Copper, total [as Cu] | 8 | 0 | 0 | ||
| Iron, total [as Fe] | 8 | 0 | 0 | ||
| Lead, total [as Pb] | 8 | 0 | 0 | ||
| Nickel, total [as Ni] | 8 | 0 | 0 | ||
| Silver, total [as Ag] | 8 | 0 | 0 | ||
| Zinc, total [as Zn] | 8 | 0 | 0 | ||
| Antimony, total [as Sb] | 8 | 0 | 0 | ||
| Selenium, total [as Se] | 8 | 0 | 0 | ||
| Mercury, total [as Hg] | 8 | 0 | 0 |
EPA’s effluent violation file records no exceedance of a numeric limit for NPDES MTR000503.
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 MTR000503.
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
One permit holder, $99/month. Watch the register for one permit holder and the places and receiving waters tied to its permits. Choose “One permit holder” and enter this permit’s NPDES ID, MTR000503.
Start the watch
- One permit holder — $99/month
- One watershed — $2,990/year
- One state — $4,990/year
- The whole register — $18,000/year
How we handle your data → Privacy
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 MTR000503 there.
Nearby on the register
- Discharge permits in Big Timber
- Every permit record in Big Timber, A to Z
- Discharge permits in Montana
- Every permit record in Montana, A to Z
Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.