Data / Mines / California / Blue Moon Underground Mine
Blue Moon Underground Mine: 5 MSHA citations
Updated November 6, 2026. Source: US Department of Labor, Mine Safety and Health Administration (MSHA), Open Government Data Sets.
Blue Moon Underground Mine is an active zinc underground mine in Mariposa County, California, operated by Small Mine Development with 5 employees on MSHA's record (mine ID 0405990). Since January 1, 2022 MSHA inspectors issued 5 citations and orders there with $755 in proposed penalties, and 0 accident reports were filed there, with no injury or illness cases.
The request: Watch Blue Moon Underground Mine (MSHA mine ID 0405990) in Mariposa County, California: each new citation and each accident report. $10 of work on sign-up, no card.
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- MSHA mine ID
- 0405990
- Status
- Active since November 25, 2025
- Main commodity
- Zinc
- Mine type
- Underground
- County
- Mariposa County, California
- Nearest town
- Hornitos
- Operator
- Small Mine Development
- Employees
- 5
- MSHA field office
- Vacaville CA Field Office
- Citations and orders since January 1, 2022
- 5
- Significant and substantial
- 0 (0.0%)
- Closure orders
- 0
- High negligence or reckless
- 0
- Proposed penalties
- $755
- Amount paid so far
- $755
- Inspections
- 5
- Inspector hours on site
- 47
- Citations per inspection
- 1.00 (all mines 2.30)
- Accident reports
- 0
- Injury and illness cases
- 0
- Fatalities
- 0
- Latest MSHA record
- July 23, 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 |
|---|---|---|---|---|
| 2025 | 1 | 0 | $151 | 0 |
| 2026 | 4 | 0 | $604 | 0 |
Standards cited most at Blue Moon Underground Mine
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 57.6132 | Underground metal and nonmetal mines | 1 |
| 30 CFR 57.6201 | Underground metal and nonmetal mines | 1 |
| 30 CFR 57.13001 | Underground metal and nonmetal mines | 1 |
| 30 CFR 47.41 | Hazard communication | 1 |
| 30 CFR 49.3 | Mine rescue teams | 1 |
Other open mines in Mariposa County, California
| Mine | Operator | County | Main commodity | Employees | Citations since 2022 |
|---|
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.