citations per 100 inspection hours
ⓘThis rate is recorded citations divided by MSHA inspection hours, per 100 hours. It reflects inspection effort, not mine size or production.
117 citations across 1,067 inspection hours.
Source: MSHA inspections data, updated weekly.
Thornton Plant has $34K in proposed MSHA penalties and $0 outstanding across 1 contested dockets.
Penalty disposition
ⓘDifferences between proposed and paid penalties reflect both settlements and conference reductions and amounts still owed. Outstanding is the balance currently owed.
$34K
proposed penalties
$33K
current assessed
$33K
paid to date
$0
outstanding
117 assessments are final orders; 1 contested dockets.
Of $6K in penalties contested before the Commission, $5K was upheld in final decisions.
As of the most recent assessment on 2026-05-12.
Source: MSHA assessed-violations and conference/litigation data, updated weekly.
Violation severity profile
ⓘShares are computed over citations that carry the MSHA gravity and negligence coding; a small share of records are uncoded.
Source: MSHA violations gravity and negligence coding, updated weekly.
When citations were contested
ⓘContesting a citation before the Federal Mine Safety and Health Review Commission is a lawful right. These figures state the public outcomes of that process, from MSHA's Contested Violations file.
1citations taken to the federal commission · 1% of citations on record
Settled
1 · 100%
100%
S&S designation survived the contest
ⓘCounts a Significant & Substantial citation as surviving when a settlement or judge's decision kept the designation, or the contest was dismissed or defaulted so the citation stands as issued. Vacated and withdrawn citations, and settlements that removed the designation, count against.
of 1 decided S&S contests · industry: 79%
20%
Penalty reduction in decided contests
$6K proposed, $5K after decisions · industry: 39%
Source: MSHA Contested Violations file (public record), updated weekly. A dismissed or defaulted contest leaves the citation standing as issued; a vacated or withdrawn citation is removed from the violation record. Latest contest filed 2012-09-05.
Contested penalties
ⓘA reduction or dismissal at the Commission is a lawful outcome of contesting a proposed penalty. Figures are the proposed amount and the amount upheld in the docket's decision.
Largest penalties this mine contested before the Federal Mine Safety and Health Review Commission, with the outcome on record.
Health sampling
ⓘA sample is a point in time compliance measurement, not an individual exposure history. These figures describe MSHA sampling records and do not establish causation or personal dose.
Metal and nonmetal contaminants (personal samples)
ⓘMany samples are screening measurements of substances with no applicable exposure limit; they are counted as samples but excluded from every over-limit figure. Over-limit shares use only limit-tested samples.
Last sampled: 2025-10-22
0%
of limit-tested samples over the exposure limit
14
samples
4
limit-tested
Most sampled contaminants
Quartz, respirable, >1% Qtz6
Respirable dust, <.1mg6
Unlisted Particulate, respirable, <1% Qtz2
Show the individual readings (14)
Date
Contaminant
Concentration
Limit
Conc / limit
Occupation
2025-10-22
Respirable dust, <.1mg
0
Supervisor, Co. Official
2023-03-15
Respirable dust, <.1mg
0
Truck Loader
2023-03-15
Respirable dust, <.1mg
0
Front-end Loader Operator
2021-06-15
Quartz, respirable, >1% Qtz
0.27
Kiln/Dryer Operator
2021-06-15
Respirable dust, <.1mg
0
Front-end Loader Operator
2021-06-15
Quartz, respirable, >1% Qtz
0.21
Kiln/Dryer Operator
2015-01-07
Respirable dust, <.1mg
0
Laborer, Bullgang
2015-01-07
Respirable dust, <.1mg
0
Laborer, Bullgang
2013-03-06
Unlisted Particulate, respirable, <1% Qtz
0.12
Laborer, Bullgang
2013-03-06
Unlisted Particulate, respirable, <1% Qtz
0.59
Front-end Loader Operator
2013-03-06
Quartz, respirable, >1% Qtz
0.19
1.54
0.12
Kiln/Dryer Operator
2011-01-06
Quartz, respirable, >1% Qtz
0.42
1.58
0.27
Laborer, Bullgang
2011-01-06
Quartz, respirable, >1% Qtz
0.41
1.22
0.34
Kiln/Dryer Operator
2004-07-29
Quartz, respirable, >1% Qtz
0.13
1.08
0.12
Kiln/Dryer Operator
Source: MSHA respirable dust, quartz, and noise sampling records, updated weekly. Metal/nonmetal contaminant figures come from MSHA's Personal Health Samples and Area Samples files (public record), updated weekly.
Thornton Plant recorded 0.00 reportable injury cases per 100 full-time workers in 2014.
Injury rate, 2014
ⓘThis rate is reportable injury cases per 100 full-time-equivalent workers per year, computed as 200,000 times cases divided by MSHA operator-reported employee-hours. Cases are injuries MSHA graded degree 01 through 07; accident-only events that hurt no one are excluded, and so are contractor injuries, whose hours do not attach to a single mine. Rates begin in 2000, when quarterly employment reporting starts, and are withheld below 20,000 hours in a year.
0.00
total case rate
0.00
days-away rate
0.000
fatality rate
Below average. The US metal and nonmetal mining average was 2.39 and the all-US-mining average was 2.93 cases per 100 workers.
In Wyoming, metal and nonmetal mining averaged 2.19 cases per 100 workers that year.
Under 100,000 employee-hours were reported that year, so a single case moves the rate by two or more. Read the figure as approximate.
Year
total case rate
days-away
fatal
2014 *
0.00
0.00
0.000
2012 *
8.52
8.52
0.000
2011 *
0.00
0.00
0.000
2010 *
27.34
18.23
0.000
2009 *
0.00
0.00
0.000
2008 *
9.01
9.01
0.000
* Fewer than 100,000 employee-hours that year; the rate is less stable.
Source: injury cases from MSHA accident and injury records; employee-hours from MSHA quarterly employment reports. Rate is cases per 100 full-time-equivalent workers, operator employees only.
Source: MSHA controller and operator history, updated weekly.
Workforce and production
Year
Employees
2026
2
2025
4
2024
5
2023
7
2022
8
2021
6
2020
7
2019
7
2018
6
2017
6
2016
6
2015
9
2014
7
2013
6
2012
9
2011
8
2010
8
2009
8
2008
8
2007
4
2006
4
2005
2
2004
2
2003
2
2002
3
2001
3
Source: MSHA quarterly employment and production, updated weekly.
Thornton Plant sits in Weston County, Wyoming, where the Census mining category is 14.4% of county employment.
Local economic context
ⓘCounty figures come from the US Census Bureau's American Community Survey, 5-year pooled estimates, so the 2023 vintage covers 2019 through 2023. The Census category is 'mining, quarrying, and oil and gas extraction', which is broader than MSHA jurisdiction and includes oil and gas workers no mine employs. These figures describe the surrounding county, not this mine, and are not a factor in any specific incident.
Weston County, Wyoming · Population 6,835
14.4%
Mining share of county employment
$87,545
Median household income
Source: US Census Bureau, American Community Survey 2023 5-year estimates.
Quarterly safety rates
ⓘCitations per million reported employee-hours. Rates begin in 2000, when MSHA's quarterly employment data starts; earlier incidents are counted but cannot be rate-adjusted. Quarters under 100,000 reported hours are greyed: too few hours for a stable rate.
Citations per million employee-hours, as reported to MSHA
Quarter
Hours worked
Citations
S&S
Per 1M hrs
2026 Q2
835
2
1
2395.2
2026 Q1
835
0
0
0.0
2025 Q4
776
2
0
2577.3
2025 Q3
332
0
0
0.0
2025 Q2
2,542
2
0
786.8
2025 Q1
3,650
0
0
0.0
2024 Q4
3,115
4
0
1284.1
2024 Q3
3,458
0
0
0.0
Show 91 earlier quartersHide earlier quarters
Quarter
Hours worked
Citations
S&S
Per 1M hrs
2024 Q2
3,172
3
1
945.8
2024 Q1
2,731
5
1
1830.8
2023 Q4
3,716
0
0
0.0
2023 Q3
2,834
0
0
0.0
2023 Q2
5,026
0
0
0.0
2023 Q1
4,490
3
0
668.2
2022 Q4
4,833
0
0
0.0
2022 Q3
4,761
0
0
0.0
2022 Q2
5,216
5
1
958.6
2022 Q1
3,800
0
0
0.0
2021 Q4
4,605
1
0
217.2
2021 Q3
3,497
0
0
0.0
2021 Q2
3,578
1
0
279.5
2021 Q1
3,578
0
0
0.0
2020 Q4
4,027
2
2
496.6
2020 Q3
4,268
1
0
234.3
2020 Q2
4,173
0
0
0.0
2020 Q1
4,706
0
0
0.0
2019 Q4
3,632
2
0
550.7
2019 Q3
4,499
0
0
0.0
2019 Q2
3,572
1
0
280.0
2019 Q1
4,280
0
0
0.0
2018 Q4
4,099
3
0
731.9
2018 Q3
4,456
0
0
0.0
2018 Q2
3,477
3
0
862.8
2018 Q1
3,743
4
1
1068.7
2017 Q4
2,827
0
0
0.0
2017 Q3
3,487
0
0
0.0
2017 Q2
3,373
1
0
296.5
2017 Q1
3,849
4
0
1039.2
2016 Q4
2,667
0
0
0.0
2016 Q3
1,936
0
0
0.0
2016 Q2
1,950
3
1
1538.5
2016 Q1
5,445
0
0
0.0
2015 Q4
4,466
5
2
1119.6
2015 Q3
3,865
0
0
0.0
2015 Q2
4,311
0
0
0.0
2015 Q1
5,413
0
0
0.0
2014 Q4
6,330
0
0
0.0
2014 Q3
4,845
0
0
0.0
2014 Q2
4,773
0
0
0.0
2014 Q1
4,495
0
0
0.0
2013 Q4
4,112
4
0
972.8
2013 Q3
3,610
0
0
0.0
2013 Q2
4,040
0
0
0.0
2013 Q1
3,436
0
0
0.0
2012 Q4
4,236
0
0
0.0
2012 Q3
5,339
0
0
0.0
2012 Q2
7,125
8
2
1122.8
2012 Q1
6,770
2
1
295.4
2011 Q4
5,911
0
0
0.0
2011 Q3
5,672
0
0
0.0
2011 Q2
4,405
8
2
1816.1
2011 Q1
4,555
5
3
1097.7
2010 Q4
4,308
0
0
0.0
2010 Q3
5,479
0
0
0.0
2010 Q2
5,376
0
0
0.0
2010 Q1
6,784
12
6
1768.9
2009 Q4
5,163
1
0
193.7
2009 Q3
6,054
0
0
0.0
2009 Q2
5,310
0
0
0.0
2009 Q1
5,046
1
0
198.2
2008 Q4
5,680
1
0
176.1
2008 Q3
6,050
0
0
0.0
2008 Q2
5,822
0
0
0.0
2008 Q1
4,656
2
0
429.6
2007 Q4
4,087
0
0
0.0
2007 Q3
3,927
0
0
0.0
2007 Q2
2,964
0
0
0.0
2007 Q1
2,226
0
0
0.0
2006 Q4
2,662
0
0
0.0
2006 Q3
2,596
0
0
0.0
2006 Q2
2,025
0
0
0.0
2006 Q1
2,447
0
0
0.0
2005 Q4
1,608
0
0
0.0
2005 Q3
1,810
0
0
0.0
2005 Q2
1,007
0
0
0.0
2005 Q1
1,596
0
0
0.0
2004 Q4
1,570
0
0
0.0
2004 Q3
1,111
4
0
3600.4
2004 Q2
1,873
0
0
0.0
2004 Q1
1,396
1
0
716.3
2003 Q4
1,345
0
0
0.0
2003 Q3
1,272
1
0
786.2
2003 Q2
153
0
0
0.0
2003 Q1
1,908
1
0
524.1
2002 Q4
1,733
0
0
0.0
2002 Q3
2,075
2
0
963.9
2002 Q2
1,771
0
0
0.0
2002 Q1
2,372
5
1
2107.9
2001 Q4
2,097
0
0
0.0
No fatalities recorded at this mine.
Reportable incidents
19 on file
2024 · 4 incidents
August 20, 2024WY · Metal/Non-Metalball/rod/pebble/hand/limestone/dry mill operator, roller operatorHANDTOOLS (NONPOWERED)
Miner was walking into plant when miner slipped and fell onto knee. The following day, the miner experienced swelling and pain. The miner was evaluated by a physician on 5-15-2024 and was advised to rest at home for 2 days while applying ice to injured knee.
Employee was lifting a pipe bender off the ground and felt a pop in the left elbow. EE did not seek immediate medical attention, but the pain didn't go away. Doctors visit was scheduled for 02/01/2024. Employee is now out of work.
January 11, 2024WY · Metal/Non-Metalfront-end loader, scraper-loader operator, pan operator, payloader, scraper rig operatorSLIP OR FALL OF PERSON
Employee started feeling unwell shortly after arriving on shift. At 11:40pm plant employees took the ill miner to the ER. The hospital could not give a definitive diagnosis and the employee is currently waiting to see a specialist for a proper diagnosis and treatment and is off work at this time.
2021 · 1 incident
April 16, 2021WY · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorHANDLING OF MATERIALS
Employee was shoveling dirt when they felt a pop in their back. Reported the injury to the shift supervisor, and informed them at that time they were able to work with no issue. On Sunday 04/18/2021 the employee informed the supervisor that they were experiencing numbness and wanted to go to the doctor on 04/19/2021.
2020 · 1 incident
April 14, 2020WY · Metal/Non-Metaldry screening plant operator, screen house operatorHANDLING OF MATERIALS
Employee was picking up a head pulley shaft, when they strained their lower back. did not notify management until the next day when they called in to work.
2017 · 1 incident
November 1, 2017WY · Metal/Non-Metalbulldozer operator, universal operator, heavy equipment operator, operating engineerHANDTOOLS (NONPOWERED)
Employee was shoveling material off the rail road track, when ee dropped the shovel and it hit the top of ee's hand.
2013 · 2 incidents
September 9, 2013WY · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorSLIP OR FALL OF PERSON
EE was climbing down from front-end loader and slipped from second step in wet conditions and pulled muscles in left shoulder. Several days will be missed.
EE was running Front-end loader when he got out to unhook a tow rope. While climbing back into the loader he felt a pop in his left calf. He went to clinic to see a doctor who diagnosed a strained calf muscle. Ice and rest were recommended.
2012 · 1 incident
February 22, 2012WY · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorSLIP OR FALL OF PERSON
EE was lifting heavy metal plates from a hammer-mill in a constricted location. This caused the lifting to be awkward and in various positions. Trauma was done to the trunk of the body, most likely resulting in a hernia. The doctor has not yet been consulted and no time has been missed as of this point; on self imposed lite duty restriction.
September 21, 2010WY · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorMACHINERY
EE was helping change hammers in a hammer-mill when a hammer got caught and caused the rotor to change directions. It spun backwards and caught the pry bar the EE was holding onto, causing it to swing and strike him in the lower chin area. This action resulted in many teeth being fractured and three stitches in the lower jaw.
EE was shoveling bentonite and strained lower back. Attempts to run 627G scraper on the 17th and 18th met with severe pain. EE went to doctor on the 18th and was given a no work slip until 05/24/2010, at which time he returned to full capacity.
Employee was grinding inside of fire-box when a piece of metal by-passed his protective eyewear and lodged in his right eye. He went to doctor the following morning and had it extracted, causing him to miss one day of work.
2005 · 1 incident
April 6, 2005WY · Metal/Non-Metalassayer, geologist, metallurgist, engineer, engineer managementHANDLING OF MATERIALS
Employee was reaching for a railcar lid that had been blown by the wind and felt a sensation in lower back area. He will take a few days off to allow healing.
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