Mining Incidents

Thornton Plant Metal/Non-Metal

Upton, Weston County, WY  ·  Intermittent
MSHA Mine ID: 4801042

Thornton Plant has $34K in proposed MSHA penalties and $302 outstanding across 1 contested dockets, plus health sampling and the full incident record.

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Fatalities
0
Total incidents
19
Years on record
2005–2024
Latest incident
Aug 2024
Compliance record
MSHA citations since 2002
117
citations
25
significant & substantial
$34,460
proposed penalties
$32,966
paid to date
96% of proposed penalties paid to date, a $1,494 gap.
Source: MSHA violations data, updated weekly.
Inspection activity
MSHA inspections since 2002
70
inspections on record
1,067
inspection hours
11.0
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 $302 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
$302
outstanding
115 assessments are final orders; 1 contested dockets.
As of the most recent assessment on 2026-05-12.
Source: MSHA assessed-violations and conference/litigation data, updated weekly.
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
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
2024 Q2 3,172 3 1 945.8
2024 Q1 2,731 5 1 1830.8
Show 89 earlier quarters
Quarter Hours worked Citations S&S Per 1M hrs
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 4 0 975.8
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 3 0 644.3
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

May 14, 2024 WY · Metal/Non-Metal prep plant foreman, supervisor, mill plant supervisor, kiln supervisor SLIP OR FALL OF PERSON
Black Hills Bentonite A Limited Liability Co · Fall to the walkway or working surface

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.

January 31, 2024 WY · Metal/Non-Metal electrician, lineman HANDLING OF MATERIALS
Black Hills Bentonite A Limited Liability Co · Over-exertion in lifting objects

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.

2023 · 2 incidents

December 16, 2023 WY · Metal/Non-Metal dry screening plant operator, screen house operator HANDTOOLS (NONPOWERED)
Black Hills Bentonite A Limited Liability Co · Struck by... (Not Elsewhere Classified)

employee was attempting to close a chop gate by hitting it with a hammer when they missed and struck their left hand and wrist with the hammer.

2022 · 1 incident

June 1, 2022 WY · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator OTHER
Black Hills Bentonite A Limited Liability Co · Unclassified, insufficient data

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, 2021 WY · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator HANDLING OF MATERIALS
Black Hills Bentonite A Limited Liability Co · Over-exertion in lifting objects

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, 2020 WY · Metal/Non-Metal dry screening plant operator, screen house operator HANDLING OF MATERIALS
Black Hills Bentonite A Limited Liability Co · Over-exertion in lifting objects

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, 2017 WY · Metal/Non-Metal bulldozer operator, universal operator, heavy equipment operator, operating engineer HANDTOOLS (NONPOWERED)
Black Hills Bentonite A Limited Liability Co · Struck by... (Not Elsewhere Classified)

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, 2013 WY · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator SLIP OR FALL OF PERSON
Black Hills Bentonite A Limited Liability Co · Over-exertion (Not Elsewhere Classified)

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.

July 15, 2013 WY · Metal/Non-Metal prep plant foreman, supervisor, mill plant supervisor, kiln supervisor POWERED HAULAGE
Black Hills Bentonite A Limited Liability Co · Over-exertion (Not Elsewhere Classified)

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

2010 · 3 incidents

September 27, 2010 WY · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator HANDLING OF MATERIALS
Black Hills Bentonite A Limited Liability Co · Over-exertion in lifting objects

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, 2010 WY · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator MACHINERY
Black Hills Bentonite A Limited Liability Co · Struck by... (Not Elsewhere Classified)

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.

May 15, 2010 WY · Metal/Non-Metal ledgeman/hand, quarry man HANDLING OF MATERIALS
Black Hills Bentonite A Limited Liability Co · Over-exertion in lifting objects

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.

2008 · 1 incident

2007 · 1 incident

July 16, 2007 WY · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator MACHINERY

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, 2005 WY · Metal/Non-Metal assayer, geologist, metallurgist, engineer, engineer management HANDLING OF MATERIALS
Black Hills Bentonite A Limited Liability Co · Over-exertion (Not Elsewhere Classified)

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.

For insurers, brokers, and safety consultants

The full compliance file on Thornton Plant

A dated report covering the 26-year penalty trail, line-item violation pattern, contest and docket posture, rate-normalized peer benchmark, and full fatality history. Delivered as a PDF with the underlying data as CSV.