Data / Mines / California / San Luis Obispo County
Mines in San Luis Obispo County, California: 10 open mines
Updated November 6, 2026. Source: US Department of Labor, Mine Safety and Health Administration (MSHA), Open Government Data Sets.
MSHA lists 10 open mines in San Luis Obispo County, California, run by 6 operators and employing 59 people. Since January 1, 2022 its inspectors issued 121 citations and orders there with $43,320 in proposed penalties, and operators reported 7 injury or illness cases. The operators with the most open mines are David Crye General Engineering Contractor, Inc.; CalPortland Company; Viborg Sand & Gravel Inc. Data from MSHA, November 6, 2026.
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- Open mines
- 10
- Operators
- 6
- Employees
- 59
- Active
- 6
- Intermittent
- 4
- Citations and orders since January 1, 2022
- 121
- Significant and substantial
- 29 (24.0%)
- Closure orders
- 4
- High negligence or reckless
- 14
- Proposed penalties
- $43,320
- Amount paid so far
- $42,867
- Inspections
- 100
- Inspector hours on site
- 556
- Citations per inspection
- 1.21 (all mines 2.30)
- Accident reports
- 7
- Injury and illness cases
- 7
- Fatalities
- 0
- Latest MSHA record
- September 14, 2026
Operators with the most open mines in San Luis Obispo County, California
Ranked by open mines, then by citations. Sole proprietors and individuals are not listed.
| Operator | Open mines | Employees | Citations since 2022 | Proposed penalties | Injury cases |
|---|---|---|---|---|---|
| David Crye General Engineering Contractor, Inc. | 3 | 10 | 38 | $7,077 | 0 |
| CalPortland Company | 2 | 17 | 19 | $7,122 | 4 |
| Viborg Sand & Gravel Inc | 2 | 2 | 7 | $1,207 | 0 |
| Blue Mountain Minerals PR LLC | 1 | 12 | 29 | $12,607 | 2 |
| Martin Marietta Northern California Aggregates,LLC | 1 | 13 | 17 | $13,191 | 1 |
| Negranti & Sons | 1 | 5 | 11 | $2,116 | 0 |
Operators with the most citations in San Luis Obispo County, California
Citations and orders issued since January 1, 2022 at their open mines here.
| Operator | Open mines | Employees | Citations since 2022 | Proposed penalties | Injury cases |
|---|---|---|---|---|---|
| David Crye General Engineering Contractor, Inc. | 3 | 10 | 38 | $7,077 | 0 |
| Blue Mountain Minerals PR LLC | 1 | 12 | 29 | $12,607 | 2 |
| CalPortland Company | 2 | 17 | 19 | $7,122 | 4 |
| Martin Marietta Northern California Aggregates,LLC | 1 | 13 | 17 | $13,191 | 1 |
| Negranti & Sons | 1 | 5 | 11 | $2,116 | 0 |
| Viborg Sand & Gravel Inc | 2 | 2 | 7 | $1,207 | 0 |
Mines with the most citations
Open mines, ranked by citations and orders since January 1, 2022.
| Mine | Operator | County | Main commodity | Employees | Citations since 2022 |
|---|---|---|---|---|---|
| Blue Mountain Minerals PR LLC | Blue Mountain Minerals PR LLC | San Luis Obispo County, CA | Crushed, broken limestone | 12 | 29 |
| Rocky Canyon Plant | CalPortland Company | San Luis Obispo County, CA | Crushed, broken granite | 14 | 19 |
| Bianchi Pit | David Crye General Engineering Contractor, Inc. | San Luis Obispo County, CA | Construction sand and gravel | 5 | 19 |
| Santa Margarita Aggregates | Martin Marietta Northern California Aggregates,LLC | San Luis Obispo County, CA | Construction sand and gravel | 13 | 17 |
| Navajo Rock & Block | David Crye General Engineering Contractor, Inc. | San Luis Obispo County, CA | Construction sand and gravel | 2 | 13 |
| Whale Rock Quarry | Negranti & Sons | San Luis Obispo County, CA | Crushed, broken stone | 5 | 11 |
| Warrior 1800/Cone Crusher FT200 | David Crye General Engineering Contractor, Inc. | San Luis Obispo County, CA | Sand, industrial | 3 | 6 |
| MTN Springs RD. Pit | Viborg Sand & Gravel Inc | San Luis Obispo County, CA | Construction sand and gravel | 1 | 4 |
| Estrella Sand Pit | Viborg Sand & Gravel Inc | San Luis Obispo County, CA | Sand, industrial | 1 | 3 |
| Paso Robles Plant | CalPortland Company | San Luis Obispo County, CA | Construction sand and gravel | 3 | 0 |
Main commodities
| Main commodity | Open mines | Share |
|---|---|---|
| Construction sand and gravel | 5 | 50% |
| Sand, industrial | 2 | 20% |
| Crushed, broken limestone | 1 | 10% |
| Crushed, broken granite | 1 | 10% |
| Crushed, broken stone | 1 | 10% |
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 | 46 | 10 | $19,252 | 1 |
| 2023 | 24 | 7 | $9,414 | 1 |
| 2024 | 30 | 9 | $11,375 | 1 |
| 2025 | 10 | 1 | $1,510 | 0 |
| 2026 | 11 | 2 | $1,769 | 4 |
Standards cited most at mines in San Luis Obispo County, California
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 56.20003 | Surface metal and nonmetal mines | 16 |
| 30 CFR 56.14107 | Surface metal and nonmetal mines | 12 |
| 30 CFR 50.30 | Reporting of accidents, injuries and illnesses | 12 |
| 30 CFR 56.14112 | Surface metal and nonmetal mines | 8 |
| 30 CFR 56.9300 | Surface metal and nonmetal mines | 8 |
| 30 CFR 56.12004 | Surface metal and nonmetal mines | 5 |
| 30 CFR 46.7 | Training at sand, gravel and surface stone mines | 4 |
| 30 CFR 56.11001 | Surface metal and nonmetal mines | 4 |
| 30 CFR 56.12032 | Surface metal and nonmetal mines | 4 |
| 30 CFR 56.11012 | Surface metal and nonmetal mines | 3 |
| 30 CFR 56.18002 | Surface metal and nonmetal mines | 3 |
| 30 CFR 56.14130 | Surface metal and nonmetal mines | 3 |
| 30 CFR 56.16001 | Surface metal and nonmetal mines | 2 |
| 30 CFR 56.16005 | Surface metal and nonmetal mines | 2 |
| 30 CFR 56.12019 | Surface metal and nonmetal mines | 2 |
Injury and illness cases at mines in San Luis Obispo County, California
Accident reports by degree of injury, as the operator reported them to MSHA.
| Degree | Cases |
|---|---|
| Days away from work or restricted activity | 6 |
| No lost time, or an occupational illness | 1 |
What the accident reports at mines in San Luis Obispo County, California describe
Accident classification, as MSHA codes the circumstances that contributed most directly.
| Classification | Reports |
|---|---|
| Handling of materials | 4 |
| Slip or fall of person | 2 |
| Handtools (nonpowered) | 1 |
Equipment named in accident reports at mines in San Luis Obispo County, California
| Equipment | Reports |
|---|---|
| Hand tools (not powered) | 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.