Key Takeaway
Thunder Mountain Quarry is a active surface mine producing Stone, located in Enumclaw, King County, WA. It has 94 violations on record (20 S&S) and $13K in proposed penalties. Operated by HM Pacific Northwest, Inc..
Thunder Mountain Quarry
Operator: HM Pacific Northwest, Inc.
Controller: Heidelberg Materials AG
Location: Enumclaw, King County, WA
Employees: 3
Recent Violations
View all 94 →| Date | Section | S&S | Negligence | Penalty |
|---|---|---|---|---|
| 10/23/2025 | 56.14105 | S&S | ModNegligence | $755 |
| 07/15/2025 | 56.9300(b) | S&S | ModNegligence | $226 |
| 01/30/2025 | 56.11003 | Non-S&S | ModNegligence | $151 |
| 01/30/2025 | 56.11001 | Non-S&S | ModNegligence | $151 |
| 06/18/2024 | 56.12028 | Non-S&S | ModNegligence | $147 |
| 06/18/2024 | 56.11001 | S&S | ModNegligence | $736 |
| 06/18/2024 | 56.11001 | S&S | ModNegligence | $736 |
| 03/28/2024 | 56.14108 | Non-S&S | LowNegligence | $147 |
| 03/28/2024 | 56.14107(a) | Non-S&S | LowNegligence | $147 |
| 03/28/2024 | 56.14132(b)(2) | Non-S&S | ModNegligence | $147 |
| 04/28/2023 | 56.14100(b) | Non-S&S | ModNegligence | $143 |
| 03/21/2022 | 50.20-1 | Non-S&S | ModNegligence | $133 |
| 03/21/2022 | 47.51(b) | Non-S&S | ModNegligence | $133 |
| 03/17/2022 | 56.14100(a) | Non-S&S | ModNegligence | $133 |
| 03/17/2022 | 56.14101(a)(2) | Non-S&S | ModNegligence | $133 |
| 03/17/2022 | 56.12028 | Non-S&S | ModNegligence | $133 |
| 03/17/2022 | 56.14105 | Non-S&S | ModNegligence | $133 |
| 03/17/2022 | 56.16005 | Non-S&S | ModNegligence | $133 |
| 05/05/2021 | 56.11001 | S&S | ModNegligence | $279 |
| 01/19/2021 | 47.41(a) | Non-S&S | ModNegligence | $125 |
Accidents & Injuries
View all 7 →| Date | Classification | Injury | Days Lost |
|---|---|---|---|
| 01/20/2022 | SLIP OR FALL OF PERSON | DAYS RESTRICTED ACTIVITY ONLY | 37d restricted |
| 04/14/2021 | OTHER | NO DYS AWY FRM WRK,NO RSTR ACT | None |
| 10/04/2010 | MACHINERY | NO DYS AWY FRM WRK,NO RSTR ACT | None |
| 10/20/2009 | STEPPING OR KNEELING ON OBJECT | DAYS RESTRICTED ACTIVITY ONLY | 3d restricted |
| 04/01/2008 | MACHINERY | DAYS AWAY FROM WORK ONLY | 2d lost |
| 07/30/2004 | MACHINERY | DAYS AWAY FROM WORK ONLY | 1d lost |
| 09/20/2000 | HANDLING OF MATERIALS | DYS AWY FRM WRK & RESTRCTD ACT | 2d lost, 20d restricted |
Inspections
View all 55 →| Begin | End | Hours | Inspectors |
|---|---|---|---|
| 10/20/2025 | 10/23/2025 | 7.25 | 1 |
| 07/15/2025 | 07/15/2025 | 7.50 | 1 |
| 01/30/2025 | 02/01/2025 | 9.75 | 1 |
| 06/18/2024 | 06/24/2024 | 13.75 | 1 |
| 04/02/2024 | 04/02/2024 | 1.75 | 1 |
| 03/28/2024 | 03/28/2024 | 10.25 | 1 |
| 08/16/2023 | 08/16/2023 | 7.00 | 1 |
| 04/28/2023 | 05/06/2023 | 13.25 | 1 |
| 09/15/2022 | 09/15/2022 | 13.25 | 1 |
| 06/27/2022 | 06/27/2022 | 5.50 | 1 |
Mine Details
Related Mines
Frequently Asked Questions
How many MSHA violations does Thunder Mountain Quarry have?
Thunder Mountain Quarry has 94 MSHA violations on record, of which 20 are classified as Significant & Substantial (S&S). Total proposed penalties amount to $13K.
What type of mine is Thunder Mountain Quarry?
Thunder Mountain Quarry is a Surface mine producing Stone, located in Enumclaw, King County, WA. It currently has 3 employees.
Has anyone been injured or killed at Thunder Mountain Quarry?
According to MSHA records, Thunder Mountain Quarry has 7 reported accident/injury records and 0 fatalities on file.
Who operates Thunder Mountain Quarry?
Thunder Mountain Quarry is operated by HM Pacific Northwest, Inc. and controlled by Heidelberg Materials AG. MSHA Mine ID: 4501127.