Data / Mines / California / Los Angeles County
Mines in Los Angeles County, California: 16 open mines
MSHA lists 16 open mines in Los Angeles County, California, run by 14 operators and employing 279 people. Since January 1, 2022 its inspectors issued 302 citations and orders there with $205,331 in proposed penalties, and operators reported 33 injury or illness cases, 1 of them fatal. The operators with the most open mines are CalMat Co; United Rock Products Corp; Coast Aggregates. Data from MSHA, November 6, 2026.
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- Open mines
- 16
- Operators
- 14
- Employees
- 279
- Active
- 16
- Citations and orders since January 1, 2022
- 302
- Significant and substantial
- 72 (23.8%)
- Closure orders
- 12
- High negligence or reckless
- 36
- Proposed penalties
- $205,331
- Amount paid so far
- $157,944
- Inspections
- 238
- Inspector hours on site
- 1,894
- Citations per inspection
- 1.27 (all mines 2.30)
- Accident reports
- 34
- Injury and illness cases
- 33
- Fatalities
- 1
- Latest MSHA record
- October 30, 2026
Operators with the most open mines in Los Angeles 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 |
|---|---|---|---|---|---|
| CalMat Co | 3 | 88 | 12 | $2,352 | 6 |
| United Rock Products Corp | 1 | 35 | 80 | $72,921 | 0 |
| Coast Aggregates | 1 | 22 | 71 | $78,149 | 3 |
| Hi-Grade Materials | 1 | 13 | 59 | $30,205 | 2 |
| Granite Construction Company | 1 | 5 | 14 | $2,041 | 0 |
| Holliday Rock Company Inc | 1 | 16 | 13 | $7,462 | 2 |
| Hanson Aggregates LLC | 1 | 43 | 12 | $4,317 | 5 |
| Robertson's Ready Mix Ltd | 1 | 10 | 11 | $1,684 | 1 |
| Connolly-Pacific Company | 1 | 19 | 10 | $1,975 | 8 |
| North Star Minerals Inc | 1 | 3 | 9 | $2,629 | 3 |
| S L S & N Inc | 1 | 7 | 4 | $599 | 0 |
| 75TH Street Quarry and Recycling | 1 | 2 | 3 | $419 | 0 |
| C & M Topsoil, Inc. | 1 | 4 | 3 | $427 | 1 |
| Azusa Rock, LLC | 1 | 12 | 1 | $151 | 2 |
Operators with the most citations in Los Angeles 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 |
|---|---|---|---|---|---|
| United Rock Products Corp | 1 | 35 | 80 | $72,921 | 0 |
| Coast Aggregates | 1 | 22 | 71 | $78,149 | 3 |
| Hi-Grade Materials | 1 | 13 | 59 | $30,205 | 2 |
| Granite Construction Company | 1 | 5 | 14 | $2,041 | 0 |
| Holliday Rock Company Inc | 1 | 16 | 13 | $7,462 | 2 |
| CalMat Co | 3 | 88 | 12 | $2,352 | 6 |
| Hanson Aggregates LLC | 1 | 43 | 12 | $4,317 | 5 |
| Robertson's Ready Mix Ltd | 1 | 10 | 11 | $1,684 | 1 |
| Connolly-Pacific Company | 1 | 19 | 10 | $1,975 | 8 |
| North Star Minerals Inc | 1 | 3 | 9 | $2,629 | 3 |
| S L S & N Inc | 1 | 7 | 4 | $599 | 0 |
| 75TH Street Quarry and Recycling | 1 | 2 | 3 | $419 | 0 |
| C & M Topsoil, Inc. | 1 | 4 | 3 | $427 | 1 |
| Azusa Rock, LLC | 1 | 12 | 1 | $151 | 2 |
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 |
|---|---|---|---|---|---|
| Irwindale Plant | United Rock Products Corp | Los Angeles County, CA | Construction sand and gravel | 35 | 80 |
| Coast Aggregates Big Rock Creek | Coast Aggregates | Los Angeles County, CA | Sand, common | 22 | 71 |
| Littlerock Quarry | Hi-Grade Materials | Los Angeles County, CA | Construction sand and gravel | 13 | 59 |
| Big Rock Creek Quarry | Granite Construction Company | Los Angeles County, CA | Sand, industrial | 5 | 14 |
| Holliday Rock-Little Rock Plant | Holliday Rock Company Inc | Los Angeles County, CA | Construction sand and gravel | 16 | 13 |
| Irwindale Aggregates | Hanson Aggregates LLC | Los Angeles County, CA | Construction sand and gravel | 43 | 12 |
| Palmdale | Robertson's Ready Mix Ltd | Los Angeles County, CA | Construction sand and gravel | 10 | 11 |
| Pebbly Beach Quarry | Connolly-Pacific Company | Los Angeles County, CA | Crushed, broken stone | 19 | 10 |
| Acton Clay Quarries | North Star Minerals Inc | Los Angeles County, CA | Clay, ceramic, refractory mnls. | 3 | 9 |
| Palmdale Plant | CalMat Co | Los Angeles County, CA | Construction sand and gravel | 15 | 5 |
| Durbin Plant | CalMat Co | Los Angeles County, CA | Construction sand and gravel | 38 | 4 |
| Peck Road Gravel Pit | S L S & N Inc | Los Angeles County, CA | Construction sand and gravel | 7 | 4 |
| Reliance Plant | CalMat Co | Los Angeles County, CA | Construction sand and gravel | 35 | 3 |
| Sylmar Site | C & M Topsoil, Inc. | Los Angeles County, CA | Sand, common | 4 | 3 |
| 75TH Street Quarry and Recycling | 75TH Street Quarry and Recycling | Los Angeles County, CA | Sand, common | 2 | 3 |
| Azusa Rock | Azusa Rock, LLC | Los Angeles County, CA | Crushed, broken stone | 12 | 1 |
Main commodities
| Main commodity | Open mines | Share |
|---|---|---|
| Construction sand and gravel | 9 | 56.2% |
| Sand, common | 3 | 18.8% |
| Crushed, broken stone | 2 | 12.5% |
| Clay, ceramic, refractory mnls. | 1 | 6.2% |
| Sand, industrial | 1 | 6.2% |
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 | 64 | 15 | $26,111 | 5 |
| 2023 | 94 | 30 | $73,424 | 7 |
| 2024 | 66 | 13 | $54,494 | 12 |
| 2025 | 49 | 6 | $26,581 | 4 |
| 2026 | 29 | 8 | $24,721 | 5 |
Standards cited most at mines in Los Angeles 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 | 24 |
| 30 CFR 56.12004 | Surface metal and nonmetal mines | 21 |
| 30 CFR 56.14107 | Surface metal and nonmetal mines | 21 |
| 30 CFR 56.14100 | Surface metal and nonmetal mines | 18 |
| 30 CFR 56.12008 | Surface metal and nonmetal mines | 17 |
| 30 CFR 56.14112 | Surface metal and nonmetal mines | 15 |
| 30 CFR 56.12032 | Surface metal and nonmetal mines | 11 |
| 30 CFR 56.11001 | Surface metal and nonmetal mines | 10 |
| 30 CFR 56.18002 | Surface metal and nonmetal mines | 9 |
| 30 CFR 56.14101 | Surface metal and nonmetal mines | 7 |
| 30 CFR 56.12002 | Surface metal and nonmetal mines | 6 |
| 30 CFR 56.16001 | Surface metal and nonmetal mines | 6 |
| 30 CFR 50.30 | Reporting of accidents, injuries and illnesses | 6 |
| 30 CFR 56.4101 | Surface metal and nonmetal mines | 5 |
| 30 CFR 56.11003 | Surface metal and nonmetal mines | 5 |
Injury and illness cases at mines in Los Angeles County, California
Accident reports by degree of injury, as the operator reported them to MSHA.
| Degree | Cases |
|---|---|
| Fatality | 1 |
| Days away from work or restricted activity | 23 |
| No lost time, or an occupational illness | 9 |
What the accident reports at mines in Los Angeles County, California describe
Accident classification, as MSHA codes the circumstances that contributed most directly.
| Classification | Reports |
|---|---|
| Slip or fall of person | 10 |
| Handling of materials | 8 |
| Handtools (nonpowered) | 4 |
| Other | 2 |
| Disorders (repeated trauma) | 2 |
| Disorders (physical agents) | 2 |
| Powered haulage | 2 |
| Stepping or kneeling on object | 1 |
| Machinery | 1 |
| Poisoning (toxic materials) | 1 |
Equipment named in accident reports at mines in Los Angeles County, California
| Equipment | Reports |
|---|---|
| Front-end loader | 4 |
| Hand tools (not powered) | 4 |
| Welding machine | 2 |
| Ore haulage trucks - off highway trucks | 1 |
| Ore haulage trucks - on highway trucks | 1 |
| Bulldozer | 1 |
| Crusher | 1 |
Updated November 6, 2026. Read from US Department of Labor, Mine Safety and Health Administration (MSHA), Open Government Data Sets. 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.