Data / Mines / Colorado / Stone mines
Stone mines in Colorado: 43 open mines and MSHA citations
MSHA lists 43 open stone mines in Colorado, run by 32 operators and employing 771 people. Since January 1, 2022 its inspectors issued 1,973 citations and orders there with $3,649,329 in proposed penalties, and operators reported 115 injury or illness cases, 1 of them fatal. The operators with the most open mines are Martin Marietta Materials, Inc.; Schmidt Aggregates; Loukonen Brothers Stone. Data from MSHA, November 6, 2026.
SpecStream is the live web data engine for teams and agents. It reads the mine, citation, inspection and accident files that MSHA publishes, and this page is that reading. Ask for the mines of a commodity, state or operator with the operator's headquarters, website and size added from the web, and new mines, new citations and new accident reports arrive in your sheet, CRM, Slack or agent as MSHA posts them.
- Open mines
- 43
- Operators
- 32
- Employees
- 771
- Active
- 23
- Intermittent
- 19
- Temporarily Idled
- 1
- Mines run by individuals, counted and not listed
- 8
- Citations and orders since January 1, 2022
- 1,973
- Significant and substantial
- 312 (15.8%)
- Closure orders
- 27
- High negligence or reckless
- 162
- Proposed penalties
- $3,649,329
- Amount paid so far
- $2,984,665
- Inspections
- 533
- Inspector hours on site
- 7,128
- Citations per inspection
- 3.70 (all mines 2.30)
- Accident reports
- 125
- Injury and illness cases
- 115
- Fatalities
- 1
- Latest MSHA record
- October 30, 2026
Operators with the most open mines in Colorado
Ranked by open mines, then by citations. Sole proprietors and individuals are not listed.
Operators with the most citations in Colorado
Citations and orders issued since January 1, 2022 at their open mines here.
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 |
|---|---|---|---|---|---|
| Amrize Portland Plant | Holcim (US) Incorporated | Fremont County, CO | Cement | 175 | 644 |
| Lyons Cement Plant Cemex Inc | Cemex Construction Materials South LLC | Boulder County, CO | Cement | 89 | 257 |
| Pueblo Plant & Quarry | GCC Rio Grande Inc | Pueblo County, CO | Cement | 82 | 250 |
| Menzer Quarry | Schmidt Aggregates | El Paso County, CO | Crushed, broken stone | 25 | 54 |
| Owl Canyon Quarry & Mill | Colorado Lien Company | Larimer County, CO | Dimension limestone | 25 | 54 |
| Walstrum Quarry | Martin Marietta Materials, Inc. | Clear Creek County, CO | Crushed, broken granite | 35 | 46 |
| Stone Wholesale Brownstone Quarry | Stone Wholesale, Inc. | Larimer County, CO | Dimension stone | 12 | 45 |
| Trupp Loveland | Arkins Park Stone Corp | Larimer County, CO | Dimension sandstone | 24 | 41 |
| Ralston Quarry | Oldcastle SW Group, Inc. | Jefferson County, CO | Crushed, broken stone | 17 | 35 |
| Moffat Limestone | Anson Excavating | Moffat County, CO | Crushed, broken limestone | 8 | 35 |
| Pride of America Mine | Colorado Stone Quarries, Inc. | Gunnison County, CO | Dimension marble | 19 | 31 |
| Rocky Road Quarry | Colorado Flagstone Inc | Larimer County, CO | Dimension sandstone | 7 | 30 |
| Telluride Airport Pit | Telluride Stone Company, Inc. | San Miguel County, CO | Dimension stone | 14 | 25 |
| Portable Unit #1 | Colorado Quarries Inc | Fremont County, CO | Crushed, broken stone | 2 | 25 |
| Red Canyon Quarry | Martin Marietta Materials, Inc. | Fremont County, CO | Crushed, broken stone | 10 | 23 |
| Portable Crusher 2 | Mid-States Materials, LLC | Adams County, CO | Crushed, broken limestone | 5 | 21 |
| Sprague Stone LLC | Sprague Stone LLC | Larimer County, CO | Dimension sandstone | 11 | 20 |
| Antonito Plant (Bag Plant) | Red Hill Lava Products, Inc. | Conejos County, CO | Crushed, broken stone | 10 | 19 |
| Meadow Hollow Quarry | Colorado Quarry 1, LLC | Larimer County, CO | Dimension stone | 8 | 19 |
| Spec Agg Quarry | Martin Marietta Materials, Inc. | Jefferson County, CO | Crushed, broken sandstone | 32 | 16 |
| Masonville Quarry | Masonville Stone Company | Larimer County, CO | Dimension stone | 3 | 16 |
| Sheehan Pit | C&B Sand and Gravel | Moffat County, CO | Dimension basalt | 4 | 12 |
| McCoy Cinder Pit | Bratton Enterprises Inc | Routt County, CO | Crushed, broken stone | 3 | 11 |
| Weaver Quarry | Loukonen Brothers Stone | Larimer County, CO | Dimension sandstone | 1 | 10 |
| Beech Hill Quarry | Loukonen Brothers Stone | Boulder County, CO | Dimension sandstone | 4 | 8 |
| Mid-Continent Quarry | RMR Aggregates, Inc. | Garfield County, CO | Dimension limestone | 1 | 8 |
| Colorado Lime Company | Colorado Lime Company | Delta County, CO | Dimension limestone | 3 | 6 |
| Monarch Quarry | Colorado Lime Company | Chaffee County, CO | Crushed, broken limestone | 3 | 5 |
| Noland Quarry | Blue Mountain Stone Inc | Boulder County, CO | Dimension sandstone | 10 | 2 |
| Mencenberg Quarry | Schmidt Aggregates | Douglas County, CO | Crushed, broken stone | 3 | 2 |
| Hankins Stone Quarry #1 | TJH Stone Ltd | San Miguel County, CO | Dimension sandstone | 2 | 2 |
| 50-3-11 Rip Rap Plant Custombuilt | Aca Products Inc | Chaffee County, CO | Dimension granite | 2 | 2 |
| Barnard Quarry | Blue Mountain Stone Inc | Larimer County, CO | Dimension sandstone | 8 | 1 |
| Mesa Sandstone LLC | Mesa Sandstone LLC | Montezuma County, CO | Crushed, broken sandstone | 4 | 1 |
| Meeker Stone Company | Meeker Stone Company, LLC | Rio Blanco County, CO | Dimension sandstone | 4 | 0 |
Main commodities
| Main commodity | Open mines | Share |
|---|---|---|
| Dimension sandstone | 10 | 23.3% |
| Crushed, broken stone | 10 | 23.3% |
| Dimension stone | 5 | 11.6% |
| Crushed, broken limestone | 4 | 9.3% |
| Cement | 3 | 7% |
| Crushed, broken sandstone | 3 | 7% |
| Dimension limestone | 3 | 7% |
| Crushed, broken granite | 2 | 4.7% |
| Dimension marble | 1 | 2.3% |
| Dimension granite | 1 | 2.3% |
| Dimension basalt | 1 | 2.3% |
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 | 519 | 70 | $1,076,759 | 23 |
| 2023 | 440 | 54 | $1,404,718 | 25 |
| 2024 | 354 | 55 | $409,558 | 29 |
| 2025 | 420 | 72 | $623,642 | 25 |
| 2026 | 240 | 61 | $134,652 | 13 |
Standards cited most at stone mines in 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 | 218 |
| 30 CFR 56.12004 | Surface metal and nonmetal mines | 163 |
| 30 CFR 56.12028 | Surface metal and nonmetal mines | 149 |
| 30 CFR 56.14112 | Surface metal and nonmetal mines | 133 |
| 30 CFR 56.11001 | Surface metal and nonmetal mines | 78 |
| 30 CFR 56.14107 | Surface metal and nonmetal mines | 74 |
| 30 CFR 56.14100 | Surface metal and nonmetal mines | 74 |
| 30 CFR 56.12032 | Surface metal and nonmetal mines | 68 |
| 30 CFR 47.41 | Hazard communication | 56 |
| 30 CFR 56.4201 | Surface metal and nonmetal mines | 48 |
| 30 CFR 50.30 | Reporting of accidents, injuries and illnesses | 47 |
| 30 CFR 56.14101 | Surface metal and nonmetal mines | 43 |
| 30 CFR 56.14132 | Surface metal and nonmetal mines | 40 |
| 30 CFR 56.4101 | Surface metal and nonmetal mines | 38 |
| 30 CFR 56.16005 | Surface metal and nonmetal mines | 34 |
Injury and illness cases at stone mines in Colorado
Accident reports by degree of injury, as the operator reported them to MSHA.
| Degree | Cases |
|---|---|
| Fatality | 1 |
| Permanent disability | 2 |
| Days away from work or restricted activity | 79 |
| No lost time, or an occupational illness | 33 |
What the accident reports at stone mines in Colorado describe
Accident classification, as MSHA codes the circumstances that contributed most directly.
| Classification | Reports |
|---|---|
| Handling of materials | 34 |
| Slip or fall of person | 30 |
| Handtools (nonpowered) | 17 |
| Machinery | 13 |
| Powered haulage | 9 |
| Entrapment | 6 |
| Other | 6 |
| Fire | 2 |
| Disorders (repeated trauma) | 2 |
| All other occupational illnesses | 1 |
Equipment named in accident reports at stone mines in Colorado
| Equipment | Reports |
|---|---|
| Hand tools (not powered) | 20 |
| Elevator | 7 |
| Hand tools (powered) | 5 |
| Dimension stone machinery | 5 |
| Front-end loader | 3 |
| Ore haulage trucks - on highway trucks | 3 |
| Forklift | 2 |
| Milling machinery | 2 |
| Ore haulage trucks - off highway trucks | 2 |
| Conveyor | 2 |
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.