Data / Mines / Colorado / Jefferson County
Mines in Jefferson County, Colorado: 8 open mines
Updated November 6, 2026. Source: US Department of Labor, Mine Safety and Health Administration (MSHA), Open Government Data Sets.
MSHA lists 8 open mines in Jefferson County, Colorado, run by 7 operators and employing 117 people. Since January 1, 2022 its inspectors issued 365 citations and orders there with $338,252 in proposed penalties, and operators reported 25 injury or illness cases. The operators with the most open mines are Oldcastle SW Group, Inc.; Arcosa LWB, LLC; Burnco. Data from MSHA, November 6, 2026.
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- Open mines
- 8
- Operators
- 7
- Employees
- 117
- Intermittent
- 4
- Active
- 4
- Mines run by individuals, counted and not listed
- 1
- Citations and orders since January 1, 2022
- 365
- Significant and substantial
- 68 (18.6%)
- Closure orders
- 5
- High negligence or reckless
- 21
- Proposed penalties
- $338,252
- Amount paid so far
- $302,710
- Inspections
- 120
- Inspector hours on site
- 1,267
- Citations per inspection
- 3.04 (all mines 2.30)
- Accident reports
- 25
- Injury and illness cases
- 25
- Fatalities
- 0
- Latest MSHA record
- October 7, 2026
Operators with the most open mines in Jefferson County, Colorado
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 |
|---|---|---|---|---|---|
| Oldcastle SW Group, Inc. | 2 | 18 | 41 | $8,929 | 2 |
| Arcosa LWB, LLC | 1 | 10 | 176 | $254,205 | 10 |
| Burnco | 1 | 9 | 43 | $16,345 | 1 |
| Cmt Excavating Inc | 1 | 5 | 21 | $4,451 | 0 |
| Martin Marietta Materials, Inc. | 1 | 32 | 16 | $4,094 | 6 |
| General Shale Brick, Inc. | 1 | 1 | 0 | $0 | 0 |
Operators with the most citations in Jefferson County, Colorado
Citations and orders issued since January 1, 2022 at their open mines here.
| Operator | Open mines | Employees | Citations since 2022 | Proposed penalties | Injury cases |
|---|---|---|---|---|---|
| Arcosa LWB, LLC | 1 | 10 | 176 | $254,205 | 10 |
| Burnco | 1 | 9 | 43 | $16,345 | 1 |
| Oldcastle SW Group, Inc. | 2 | 18 | 41 | $8,929 | 2 |
| Cmt Excavating Inc | 1 | 5 | 21 | $4,451 | 0 |
| Martin Marietta Materials, Inc. | 1 | 32 | 16 | $4,094 | 6 |
| General Shale Brick, Inc. | 1 | 1 | 0 | $0 | 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 |
|---|---|---|---|---|---|
| Arcosa Boulder Plant #1604 | Arcosa LWB, LLC | Jefferson County, CO | Common shale | 10 | 176 |
| Jeffco Gravel Mine | Burnco | Jefferson County, CO | Construction sand and gravel | 9 | 43 |
| Ralston Quarry | Oldcastle SW Group, Inc. | Jefferson County, CO | Crushed, broken stone | 17 | 35 |
| Church Harvey Mine | Cmt Excavating Inc | Jefferson County, CO | Common clays | 5 | 21 |
| Spec Agg Quarry | Martin Marietta Materials, Inc. | Jefferson County, CO | Crushed, broken sandstone | 32 | 16 |
| WP 3 | Oldcastle SW Group, Inc. | Jefferson County, CO | Construction sand and gravel | 1 | 6 |
| Denver Plant 60 Clay Mines | General Shale Brick, Inc. | Jefferson County, CO | Clay, ceramic, refractory mnls. | 1 | 0 |
Main commodities
| Main commodity | Open mines | Share |
|---|---|---|
| Construction sand and gravel | 2 | 25% |
| Clay, ceramic, refractory mnls. | 1 | 12.5% |
| Common clays | 1 | 12.5% |
| Crushed, broken sandstone | 1 | 12.5% |
| Crushed, broken granite | 1 | 12.5% |
| Crushed, broken stone | 1 | 12.5% |
| Common shale | 1 | 12.5% |
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 | 82 | 20 | $112,256 | 4 |
| 2023 | 71 | 14 | $62,287 | 10 |
| 2024 | 73 | 13 | $58,534 | 6 |
| 2025 | 99 | 15 | $96,319 | 5 |
| 2026 | 40 | 6 | $8,856 | 0 |
Standards cited most at mines in Jefferson County, Colorado
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 | 39 |
| 30 CFR 56.12004 | Surface metal and nonmetal mines | 33 |
| 30 CFR 56.14107 | Surface metal and nonmetal mines | 29 |
| 30 CFR 56.14112 | Surface metal and nonmetal mines | 28 |
| 30 CFR 56.14100 | Surface metal and nonmetal mines | 21 |
| 30 CFR 56.11001 | Surface metal and nonmetal mines | 16 |
| 30 CFR 56.12028 | Surface metal and nonmetal mines | 15 |
| 30 CFR 56.12032 | Surface metal and nonmetal mines | 11 |
| 30 CFR 56.4201 | Surface metal and nonmetal mines | 10 |
| 30 CFR 56.14101 | Surface metal and nonmetal mines | 7 |
| 30 CFR 56.12018 | Surface metal and nonmetal mines | 7 |
| 30 CFR 50.30 | Reporting of accidents, injuries and illnesses | 6 |
| 30 CFR 56.14132 | Surface metal and nonmetal mines | 6 |
| 30 CFR 47.41 | Hazard communication | 6 |
| 30 CFR 56.9300 | Surface metal and nonmetal mines | 6 |
Injury and illness cases at mines in Jefferson County, Colorado
Accident reports by degree of injury, as the operator reported them to MSHA.
| Degree | Cases |
|---|---|
| Permanent disability | 3 |
| Days away from work or restricted activity | 17 |
| No lost time, or an occupational illness | 5 |
What the accident reports at mines in Jefferson County, Colorado describe
Accident classification, as MSHA codes the circumstances that contributed most directly.
| Classification | Reports |
|---|---|
| Slip or fall of person | 8 |
| Handling of materials | 7 |
| Powered haulage | 5 |
| Machinery | 2 |
| Other | 2 |
| Handtools (nonpowered) | 1 |
Equipment named in accident reports at mines in Jefferson County, Colorado
| Equipment | Reports |
|---|---|
| Front-end loader | 3 |
| Conveyor | 2 |
| Hand tools (powered) | 2 |
| Ore haulage trucks - off highway trucks | 1 |
| Hand tools (not powered) | 1 |
| Trucks | 1 |
| Shovel | 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.