Data / Mines / California / Ridge Rock Quarry
Ridge Rock Quarry: 13 MSHA citations
Updated November 6, 2026. Source: US Department of Labor, Mine Safety and Health Administration (MSHA), Open Government Data Sets.
Ridge Rock Quarry is an active construction sand and gravel surface mine in Nevada County, California, operated by Hansen Bros Enterprises with 2 employees on MSHA's record (mine ID 0405178). Since January 1, 2022 MSHA inspectors issued 13 citations and orders there with $2,805 in proposed penalties, and 2 accident reports were filed there, with 2 injury or illness cases.
The request: Watch Ridge Rock Quarry (MSHA mine ID 0405178) in Nevada County, California: each new citation and each accident report. $10 of work on sign-up, no card.
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- MSHA mine ID
- 0405178
- Status
- Active since October 25, 2016
- Main commodity
- Construction sand and gravel
- Mine type
- Surface
- County
- Nevada County, California
- Nearest town
- North San Juan
- Operator
- Hansen Bros Enterprises
- Employees
- 2
- MSHA field office
- Vacaville CA Field Office
- Citations and orders since January 1, 2022
- 13
- Significant and substantial
- 2 (15.4%)
- Closure orders
- 0
- High negligence or reckless
- 0
- Proposed penalties
- $2,805
- Amount paid so far
- $2,805
- Inspections
- 11
- Inspector hours on site
- 68
- Citations per inspection
- 1.18 (all mines 2.30)
- Accident reports
- 2
- Injury and illness cases
- 2
- Fatalities
- 0
- Latest MSHA record
- August 19, 2026
Citations and injury cases by year
Calendar years since 2022; 2026 runs to the date of the MSHA files.
| Year | Citations and orders | Significant and substantial | Proposed penalties | Injury and illness cases |
|---|---|---|---|---|
| 2022 | 2 | 0 | $286 | 0 |
| 2023 | 1 | 0 | $143 | 1 |
| 2024 | 4 | 0 | $588 | 0 |
| 2025 | 2 | 0 | $302 | 0 |
| 2026 | 4 | 2 | $1,486 | 1 |
Standards cited most at Ridge Rock Quarry
Sections of Title 30 of the Code of Federal Regulations named on the citations, with the part each belongs to.
| Standard | What the part covers | Citations |
|---|---|---|
| 30 CFR 56.15001 | Surface metal and nonmetal mines | 1 |
| 30 CFR 47.44 | Hazard communication | 1 |
| 30 CFR 50.30 | Reporting of accidents, injuries and illnesses | 1 |
| 30 CFR 56.9301 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.12004 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.9300 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.14105 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.15003 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.11001 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.14100 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.14107 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.16001 | Surface metal and nonmetal mines | 1 |
| 30 CFR 56.14207 | Surface metal and nonmetal mines | 1 |
Injury and illness cases at Ridge Rock Quarry
Accident reports by degree of injury, as the operator reported them to MSHA.
| Degree | Cases |
|---|---|
| Days away from work or restricted activity | 2 |
What the accident reports at Ridge Rock Quarry describe
Accident classification, as MSHA codes the circumstances that contributed most directly.
| Classification | Reports |
|---|---|
| Handling of materials | 1 |
| Slip or fall of person | 1 |
Equipment named in accident reports at Ridge Rock Quarry
| Equipment | Reports |
|---|---|
| Crusher | 1 |
| Front-end loader | 1 |
Other open mines in Nevada County, California
| Mine | Operator | County | Main commodity | Employees | Citations since 2022 |
|---|---|---|---|---|---|
| Greenhorn Pit & Mill | Hansen Bros Enterprises | Nevada County, CA | Construction sand and gravel | 11 | 14 |
| Martis Valley Plant | Teichert Aggregates | Nevada County, CA | Construction sand and gravel | 4 | 13 |
| Ruby Mine | Ruby Gold, Inc. | Nevada County, CA | Gold ore | 2 | 7 |
| Boca Quarry | Teichert Aggregates | Nevada County, CA | Crushed, broken stone | 14 | 2 |
| Red Ledge Mine | Red Ledge Mining Company | Nevada County, CA | Gold ore | 3 | 1 |
US government work, public domain. Counts come from the MSHA files published on November 6, 2026. An open mine is one MSHA lists as Active, Intermittent, New Mine, Temporarily Idled or NonProducing; 13,673 were open that day. Citations, penalties, inspections and accident reports run from January 1, 2022. A citation is an inspector's allegation and an operator can contest it; the penalty is the amount MSHA first proposed, before any contest or settlement. An operator is the legal entity MSHA assesses, and a parent company is its controller. Mines run by sole proprietors or by individuals are counted in every total and are not named. This page uses MSHA data and is not endorsed or certified by MSHA. Free to reuse with credit to SpecStream under CC BY 4.0. Spot a wrong value? Write to [email protected] with the link to this page.