US coal mines with the most silica in their dust samples
Respirable-dust samples at Toney Fork Surface Mine carry the highest average crystalline silica content of any US coal mine in MSHA records, at 25.6% quartz across 34 samples. Next are Patriot Mining Company Inc (24.5%) and Bent Mountain Surface Mine #2 (21.1%).
US coal mines ranked by the average crystalline silica (quartz) content of their MSHA respirable-dust samples, the fraction the 2024 federal silica rule targets. Click a mine for its full sampling and compliance record.
This is the silica share of the respirable dust that was sampled, averaged over the mine's records. It reflects the geology of the material and dust control, and is a point-in-time sampling measurement, not a personal exposure dose or a compliance judgment. Only mines with at least 30 quartz samples on record are ranked, so a stray reading cannot drive the average.
Looking at enforcement instead? See mines ranked by imminent-danger orders or by MSHA violations. For emissions, see coal mines ranked by reported methane. For hearing damage, see mines ranked by noise samples over the legal limit. This page and that one are both coal programmes; for quarries, aggregates, cement and metal mines see metal and non-metal mines measured over an exposure limit.
By state
Counts free; named roster paid
Mines where an MSHA quartz sample came back above the 50 µg/m³ permissible exposure limit for respirable crystalline silica since 2023-01-01. The worst column is a concentration in micrograms per cubic metre, so 100 is twice the limit. A sample above the limit is a measurement, not a violation finding.
| State | Mines over the limit | Samples over | Samples taken | Worst µg/m³ | Buy the named roster |
|---|---|---|---|---|---|
| WV |
101
|
366 | 8,920 | 411 | |
| KY |
55
|
179 | 4,065 | 468 | |
| PA |
35
|
77 | 2,783 | 871 | |
| VA |
18
|
62 | 1,741 | 264 | |
| AL |
13
|
55 | 1,391 | 228 | |
| IL |
13
|
74 | 2,048 | 142 | |
| IN |
8
|
32 | 1,529 | 147 | |
| CO |
5
|
37 | 424 | 188 | |
| UT |
5
|
12 | 469 | 318 | |
| OH |
4
|
9 | 198 | 129 | too thin to sell |
| MD |
3
|
6 | 145 | 678 | too thin to sell |
| WY |
3
|
4 | 189 | 121 | too thin to sell |
| AZ |
1
|
1 | 4 | 67 | too thin to sell |
| MT |
1
|
11 | 135 | 118 | too thin to sell |
| NM |
1
|
2 | 34 | 105 | too thin to sell |
The named roster for a state lists every mine over the limit ranked worst first, with the operator of record, the highest concentration, the date of the most recent sample, the site's headcount, and the occupations driving it. Where a different company held a mine while it was being sampled, that company is named too. Figures are MSHA's own published sample results over non-voided cassettes, so anything in the roster can be checked against the agency's file.
Top 100 by average respirable silica
Average quartz percent across each mine's samples
Ranked first
Toney Fork Surface Mine
Coal Mac East · WV · measured under Cliffs Logan County Coal, LLC, Greenbrier Minerals, LLC
max 55.1% · 34 samples
25.6
% avg silica
- 02 Patriot Mining Company Inc Patriot Mining Company LLC · WV 24.5% avg silica max 47.7% · 43 samples
- 03 Bent Mountain Surface Mine #2 FR Performance LLC · KY · measured under Appalachian Fuels LLC, FR Performance LLC, Kentucky Fuel Corporation, Lodestar Energy, Inc 21.1% avg silica max 50.2% · 47 samples
- 04 Holden #22 Surface Coal-Mac LLC · WV 19.9% avg silica max 47.5% · 40 samples
- 05 Virginia Point No. 1 Surface Mine Extra Energy, Inc. · VA 19.2% avg silica max 34.7% · 38 samples
- 06 Twilight Mtr Surface Mine Lexington Coal Company, LLC · WV · measured under Independence Coal Co. LLC, Lexington Coal Company, LLC, Progress Coal 18.3% avg silica max 48.1% · 46 samples
- 07 Job #49 Reckoning Reclamation,LLC. · KY · measured under Premier Elkhorn Coal Company, LLC, Virgie Clean Mining, LLC 17.9% avg silica max 40.4% · 43 samples
- 08 Broad Run Mine Big River Mining LLC · WV 17.9% avg silica max 44.5% · 33 samples
- 09 Wilson Strip #6 Buffalo Coal Company Inc · WV 17.7% avg silica max 56.3% · 44 samples
- 10 Laurel Branch Surface CW Reclaim, LLC · VA · measured under Clintwood Elkhorn Mining LLC, Clintwood JOD, LLC 17.6% avg silica max 45.3% · 61 samples
- 11 Samples Surface Mine Panther Creek Mining LLC · WV · measured under Catenary Coal Company LLC, Panther Creek Mining LLC 17.2% avg silica max 44.6% · 91 samples
- 12 Ewing Fork No. 1 Surface Mine Republic Energy LLC · WV · measured under Pioneer Fuel, Pioneer Fuel Corporation, Republic Energy Inc., Republic Energy LLC, Simmons Fork Mining, Inc. 17.1% avg silica max 36.7% · 42 samples
- 13 Speedway No 1 Strip Mine Sky Haven Coal Inc · PA 17.1% avg silica max 59.4% · 56 samples
- 14 Black Castle Mining Company, LLC Black Castle Mining Company, LLC · WV · measured under Black Castle Mining Company, LLC, Elk Run Coal Co. 17.0% avg silica max 50.6% · 32 samples
- 15 88 Strip Paramont Contura, LLC · VA · measured under Paramont Coal Company Virginia LLC, Paramont Contura, LLC 16.9% avg silica max 39.9% · 118 samples
- 16 Fishtrap Highland Energy, Inc. · AL · measured under Best Coal, Incorporated, Birmingham Coal & Coke Company Inc, Black Warrior Minerals, Inc., C&H Mining, Centennial Natural Resources, LLC, Highland Energy, Inc., Mays Mining, Inc., Rock & Roll Coal, Inc., WB Mining, LLC. 16.7% avg silica max 33.0% · 51 samples
- 17 Frasure Creek Mine No 6 Frasure Creek Mining, LLC. · KY · measured under Big Elk Mining LLC, Frasure Creek Mining, LLC., Horizon Natural Resources Co., New Ridge Mining Company, Star Fire Mining 16.6% avg silica max 47.4% · 63 samples
- 18 Mine No 1 PBS Coals, Inc. · PA 16.5% avg silica max 53.8% · 39 samples
- 19 Waroquier #1 Waroquier Coal, Inc. · PA 16.0% avg silica max 38.7% · 30 samples
- 20 Workman Creek Surface Republic Energy LLC · WV · measured under Republic Energy, Republic Energy LLC 16.0% avg silica max 32.5% · 123 samples
- 21 Republic Energy Republic Energy, LLC · WV · measured under Republic Energy, Inc, Republic Energy, LLC 15.9% avg silica max 41.1% · 62 samples
- 22 Continental Strip Keystone Anthracite Corporation · PA · measured under Girardville Coal Company, Keystone Anthracite Corporation 15.9% avg silica max 44.6% · 30 samples
- 23 Orange Strip B & N Coal Inc · OH 15.6% avg silica max 42.1% · 91 samples
- 24 Manchester Mine Black Warrior Minerals Inc · AL 15.5% avg silica max 53.1% · 38 samples
- 25 Black Knight II Elk Run Coal Company, LLC · WV 15.3% avg silica max 31.7% · 55 samples
- 26 Dry Branch Surface Mine Extra Energy, Inc. · WV 15.2% avg silica max 33.9% · 53 samples
- 27 Searles Mine No. 2, 3, 4, 5, 6, 7, 8 & 9 Southland Resources, Inc. · AL 15.2% avg silica max 35.6% · 46 samples
- 28 GRAPEVINE SOUTH SURFACE MINE APPALACHIAN RESOURCE WEST VIRGINIA, LLC · WV · measured under Appalachian Resource West Virginia, LLC, CAM Mining LLC 14.9% avg silica max 40.1% · 48 samples
- 29 Sloan Mountain Mine Iron Eagle Land Rehabilitation, LLC · AL · measured under M S & R Equipment Company Inc 14.7% avg silica max 27.8% · 52 samples
- 30 Eckman Surface Mine Extra Energy, Inc. · WV 14.2% avg silica max 41.9% · 64 samples
- 31 Three Mile Mine #1 CAM Mining LLC · KY · measured under AEP Kentucky Coal, L. L. C., Branham & Baker Coal Company Inc, CAM - Kentucky, LLC, CAM Mining LLC 14.2% avg silica max 45.6% · 31 samples
- 32 Low Gap Powellton #1 Mine Marfork Coal Company Inc · WV 14.2% avg silica max 39.9% · 38 samples
- 33 Black Warrior Mine No 1 Black Warrior Minerals, Inc. · AL 13.8% avg silica max 27.9% · 85 samples
- 34 Mine No. 1 Onyx Energy, LLC · WV · measured under Onyx Energy, LLC, Stacy Equipment and Repairs, Incorporated 13.7% avg silica max 40.6% · 52 samples
- 35 Colowyo Mine Kiewit Mining Group Inc · CO · measured under Colowyo Coal Company L P, Kiewit Mining Group Inc 13.5% avg silica max 56.3% · 57 samples
- 36 East Mac & Nellie Pine Branch Mining LLC · KY · measured under ICG Hazard, LLC, Pine Branch Mining LLC 13.3% avg silica max 45.9% · 57 samples
- 37 Stockburg No 2 Remington LLC · WV 13.2% avg silica max 42.6% · 36 samples
- 38 Feller #2 Strip Cooney Bros Coal Co · PA 13.2% avg silica max 47.4% · 49 samples
- 39 Coalburg Tunnel Mine Kanawha Eagle Mining, LLC · WV · measured under Emerald Processing, LLC., Kanawha Eagle Mining, LLC, Newtown Energy, Inc. 13.1% avg silica max 42.1% · 53 samples
- 40 Shannon Mine No. 3 RJR Mining Company, Inc. · AL 13.0% avg silica max 23.8% · 39 samples
- 41 Mine #30 R & R Mining, Inc. · KY · measured under Perry County Coal Corporation, R & R Mining, Inc., Sheep Fork Energy Inc, Tic Energy Inc, Willmack, LLC 13.0% avg silica max 21.7% · 62 samples
- 42 Combs Branch Job Pine Branch Mining LLC · KY · measured under Pine Branch Coal Sales Inc, Pine Branch Mining LLC 12.7% avg silica max 48.6% · 39 samples
- 43 White Queen Marfork Coal Company Inc · WV 12.6% avg silica max 33.7% · 63 samples
- 44 Thunder Ridge Pine Branch Mining LLC · KY · measured under ICG Hazard, LLC, KNOTT COUNTY COAL LLC, Leslie Resources Inc, Pine Branch Mining LLC 12.4% avg silica max 60.3% · 51 samples
- 45 Deep Mine # 6 Paramont Coal Company Virginia, LLC · VA · measured under Coastal Coal Company, LLC, Paramont Coal Company Virginia, LLC 12.4% avg silica max 31.3% · 69 samples
- 46 Remining #3 Appalachian Resource West Virginia, LLC · WV · measured under Appalachian Resource West Virginia, LLC, CAM Mining LLC 12.4% avg silica max 41.1% · 51 samples
- 47 Boone North No. 2 Surface Mine Eagle Horizon Resources, LLC · WV · measured under Eagle Horizon Resources, LLC, Raven Crest Contracting, LLC 12.4% avg silica max 45.7% · 30 samples
- 48 Jap Creek Mine Mays Mining, Inc. · AL · measured under Centennial Natural Resources, LLC, Job Land & Mineral Inc, Mays Mining, Inc., Reed Minerals Inc 12.2% avg silica max 26.6% · 31 samples
- 49 WAR CREEK NO. 1 Black River Coal, LLC · VA · measured under A&N Coal Co., Inc., Bandy Coal, LLC, Black River Coal, LLC, C & J Leasing Inc, CHH Mining Inc, Consolidation Coal Company, M and M Mining Inc, Sanw Inc., Tech Leasing & Rebuild Inc 12.2% avg silica max 29.0% · 35 samples
- 50 #20 Strip Job Pine Branch Mining LLC · KY · measured under Pine Branch Coal Sales Inc, Pine Branch Mining LLC 12.2% avg silica max 50.3% · 47 samples
- 51 Choctaw Mine Iron Eagle Land Rehabilitation, LLC · AL · measured under Best Coal Inc., Cedar Lake Mining, Inc., Iron Eagle Land Rehabilitation, LLC, Seminole Coal Resources LLC, Taft Coal Sales & Associates Incorporated 12.2% avg silica max 35.2% · 61 samples
- 52 CABIN RUN 97 Mining Holding Company, LLC · MD · measured under 97 Mining Holding Company, LLC, Beechwood Coal, LLC, Heritage Coal & Natural Resources,LLC, United Energy Coal Inc, Vindex Energy Corporation 12.2% avg silica max 53.5% · 42 samples
- 53 Glancy Surface Mine Rockwell Mining LLC · WV 12.0% avg silica max 41.0% · 51 samples
- 54 Logan Surface Mine Blaschak Anthracite Corporation · PA 12.0% avg silica max 40.6% · 48 samples
- 55 Eagle Mine Jet Coal Company Incorporated · KY 11.9% avg silica max 24.1% · 81 samples
- 56 Le-Ib Mine Blair Coal Company Inc · KY 11.9% avg silica max 42.2% · 44 samples
- 57 Black King I North Portal Elk Run Coal Company Inc · WV 11.7% avg silica max 32.3% · 203 samples
- 58 Ky No. Mine 1 Middle Fork Mining, Inc. · KY · measured under BR&D Enterprises Inc, Free Dome Coal Inc, Kelco Energy Inc, L & E Mining, National Coal Corporation 11.7% avg silica max 28.2% · 37 samples
- 59 Big Mountain No 16 Pine Ridge Coal Company LLC · WV 11.5% avg silica max 40.4% · 170 samples
- 60 Mine #1 Clean Energy Mining Co. · KY 11.5% avg silica max 34.7% · 155 samples
- 61 Horizon Mine Hidden Splendor Resources Inc · UT · measured under Hidden Splendor Resources Inc, Lodestar Energy, Inc 11.5% avg silica max 38.0% · 63 samples
- 62 Deep Mine 37 Paramont Contura, LLC · VA · measured under Central App. Coal Co., Dynasty Mining Inc, Paramont Coal Company Virginia LLC, Paramont Coal Company Virginia, LLC, Paramont Contura, LLC 11.5% avg silica max 36.6% · 81 samples
- 63 No 12 North Star Mining, Inc. · KY 11.3% avg silica max 24.8% · 45 samples
- 64 River Hill Coal Co., Inc. River Hill Coal Company Inc · PA 11.3% avg silica max 44.5% · 38 samples
- 65 Coalburg No 2 Mine Rio Group, Inc. · WV 11.3% avg silica max 34.1% · 31 samples
- 66 Genesis No. 17 Genesis Inc · PA 11.2% avg silica max 40.6% · 100 samples
- 67 Mine No. 1 Triple G Coal Company, Inc · WV · measured under A B & R Coal Company, Inc., Blue Haven Energy, Inc., Ruscat Enterprises Inc, Triple G Coal Company, Inc. 11.1% avg silica max 45.2% · 33 samples
- 68 Rowdy Gap Mine Pine Branch Mining LLC · KY · measured under ICG Hazard, LLC, Leslie Resources Inc, Pine Branch Mining LLC 11.1% avg silica max 42.1% · 37 samples
- 69 Jim Bridger Mine Bridger Coal Company · WY 11.0% avg silica max 16.6% · 39 samples
- 70 Mine #23 CAM Mining LLC · KY · measured under AEP Kentucky Coal, L. L. C., CAM - Kentucky, LLC, CAM Mining LLC, Coal Express Inc, Midgard Mining LLC 11.0% avg silica max 30.1% · 83 samples
- 71 Eagle No. 1 Mine Mega Highwall Mining, LLC · WV · measured under Appalachian Fuels LLC, Ben's Creek Operations WV, LLC, Glen Alum Operations, LLC, KWV Operations LLC, New Age Mining, LLC, Patton Inc 10.9% avg silica max 32.0% · 51 samples
- 72 Miller Mine RoxCoal Inc · PA · measured under K B Coal Inc, RoxCoal Inc 10.8% avg silica max 32.5% · 104 samples
- 73 No 8 Mine Patton Inc · WV 10.8% avg silica max 19.6% · 33 samples
- 74 Hawkeye Mine Knight Hawk Coal, LLC · IL 10.8% avg silica max 23.8% · 42 samples
- 75 Jims Branch No 2 Chief Mining Inc · WV 10.8% avg silica max 36.4% · 56 samples
- 76 Wildcat Hills Mine - Cottage Grove Pit Peabody Midwest Mining, LLC · IL 10.8% avg silica max 32.8% · 49 samples
- 77 Lindbergh Centennial Natural Resources, LLC · AL · measured under C & H Mining Company Inc 10.8% avg silica max 26.4% · 33 samples
- 78 Black Butte And Leucite Hills Mines Black Butte Coal Company · WY 10.6% avg silica max 20.5% · 56 samples
- 79 Mine No 9 Hubble Mining Company LLC · KY · measured under Cumberland River Coal Co Inc, Hubble Mining Company LLC 10.6% avg silica max 24.8% · 53 samples
- 80 Buffalo Deep Mine Hampden Coal LLC · WV 10.6% avg silica max 21.6% · 64 samples
- 81 Mine No. 14 Premium Coal Company,Inc. · TN · measured under National Coal Corporation, National Coal L.L.C, Premium Coal Company,Inc. 10.6% avg silica max 27.4% · 41 samples
- 82 3C A B & J Coal Co. Inc. · KY · measured under A B & J Coal Co. Inc., Dags Branch Coal Company Inc 10.6% avg silica max 25.5% · 39 samples
- 83 Lee Ranch Coal Mine Peabody Natural Resources Company · NM 10.5% avg silica max 20.9% · 38 samples
- 84 RES Houtzdale RES Coal LLC · PA 10.3% avg silica max 43.1% · 35 samples
- 85 Thompson Mine No 1 Tacoa Minerals, LLC · AL 10.3% avg silica max 19.1% · 36 samples
- 86 Narley Mine Iron Eagle Land Rehabilitation, LLC · AL · measured under Best Coal Inc 10.2% avg silica max 20.5% · 34 samples
- 87 No 2 Panzer Coal Inc · KY · measured under Coastal Coal Company, LLC, Enterprise Mining Company LLC, Panzer Coal Inc 10.2% avg silica max 29.7% · 94 samples
- 88 No 57 Mine Nufac Mining Company, Inc · WV · measured under Glow Worm Coal Co Inc, Glow Worm Coal Company, Nufac Mining Company, Inc, Pay Car Mining, Inc., Rightway Coal Company, W L Inc 10.2% avg silica max 29.5% · 43 samples
- 89 Right Fork Splint 101 Coal, Inc. · KY · measured under Civil, LLC, Coalgood Energy Co, JRL Coal Inc, JRL Coal, INC., New Horizons Coal Inc 10.2% avg silica max 56.2% · 45 samples
- 90 No 4 East Star Mining Inc · VA 10.2% avg silica max 22.0% · 39 samples
- 91 Winifrede No. 13-A Mine Rockwell Mining, LLC. · WV · measured under Banner Coal & Land Co., Long Branch Energy 10.2% avg silica max 23.9% · 34 samples
- 92 Rossmoyne No. 1 Mine Rosebud Mining Company · PA · measured under Rosebud Mining Company, T.J.S. Mining, Inc. 10.1% avg silica max 36.5% · 77 samples
- 93 R F #3 Elkhorn CAM Mining LLC · KY · measured under AEP Kentucky Coal, L. L. C., CAM - Kentucky, LLC, CAM Mining LLC, Emily Enterprises Inc 10.1% avg silica max 24.2% · 58 samples
- 94 Castle Mine Elk Run Coal Company, LLC · WV 10.1% avg silica max 34.7% · 120 samples
- 95 Mine No 4 North Fork Coal Corporation · KY 10.1% avg silica max 34.3% · 121 samples
- 96 No. 2 Hampden Coal LLC · WV · measured under Daniels Branch Coal Company Inc, Hampden Coal LLC, Rockhouse Creek Development LLC 10.0% avg silica max 31.1% · 96 samples
- 97 Allegiance Mine Independence Coal Company Inc · WV 10.0% avg silica max 22.4% · 30 samples
- 98 Coal Mountain No 1 Surface CM Energy Operations LP · WV · measured under CM Energy Operations LP, Dynamic Energy Inc 10.0% avg silica max 25.1% · 49 samples
- 99 Brushy Eagle Marfork Coal Company, LLC · WV 9.9% avg silica max 30.1% · 274 samples
- 100 5A Parton Bros. Contracting, Inc. · KY · measured under Aero Energy Inc, Gentec Processing Inc, Parton Bros. Contracting, Inc. 9.9% avg silica max 24.1% · 33 samples