Mining Incidents

O-N Minerals (Chemstone Company): 2 recorded fatalities operator

Controlled by Carmeuse Holding SA
MSHA operator ID: L16758

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Fatalities
2
Total incidents
196
Mines on record
9
Years on record
1998–2026
Compliance record
MSHA citations since 2000
1,193
citations
271
significant & substantial
$585,268
proposed penalties
$456,404
paid to date
78% of proposed penalties paid to date, a $128,864 gap.
Source: MSHA violations data, updated weekly.
Inspection activity
MSHA inspections since 2000
652
inspections on record
18,623
inspection hours
6.4
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.
1,193 citations across 18,623 inspection hours.
Source: MSHA inspections data, updated weekly.
Penalty disposition
Differences between proposed and paid penalties reflect both settlements and conference reductions and amounts still owed. Outstanding is the balance currently owed.
$581K
proposed penalties
$454K
current assessed
$453K
paid to date
$517
outstanding
1,176 assessments are final orders; 18 contested dockets.
Of $260K in penalties contested before the Commission, $128K was upheld in final decisions.
As of the most recent assessment on 2026-03-25.
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.
23.0%
significant & substantial
7.3%
high negligence or reckless
23.2%
reasonably likely or greater
58.3%
permanently disabling or fatal if injury occurs
Negligence coding: 0.1% none, 13.7% low, 78.9% moderate, 7.1% high, 0.2% reckless.
Source: MSHA violations gravity and negligence coding, updated weekly.
Injury rate, 2025
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.
0.49
total case rate
0.49
days-away rate
0.000
fatality rate
Below average. The US metal and nonmetal mining average was 1.65 and the all-US-mining average was 1.97 cases per 100 workers.
Year total case rate days-away fatal
2026 0.98 0.00 0.000
2025 0.49 0.49 0.000
2024 0.49 0.49 0.000
2023 1.49 0.37 0.000
2022 0.97 0.65 0.000
2021 2.36 1.35 0.000
2020 1.71 0.34 0.341
2019 2.04 0.68 0.000
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.
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: 2026-07-14
6%
of limit-tested samples over the exposure limit
462
samples
334
limit-tested
Most sampled contaminants
  • Nuisance dust, total, <1% Qtz4311 over
  • Diesel particulate (total carbon)909 over
  • Quartz, respirable, >1% Qtz611 over
  • Nuisance dust, respirable, <1% Qtz104

Area samples (mill and shop air)

Last sampled: 2023-02-08, 3 years ago
5
samples
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.
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.
30 citations taken to the federal commission · 3% of citations on record
  • Settled 30 · 100%
79%
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 29 decided S&S contests · industry: 79%
50%
Penalty reduction in decided contests
$248K proposed, $125K 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 2022-08-31. Vacated and withdrawn citations are removed from the file this view attributes through, so that outcome is slightly undercounted here.
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 operator contested before the Federal Mine Safety and Health Review Commission, with the outcome on record.
Docket Decision Judge Year Proposed / upheld
VA 2021-0022 Settlement 2022 $121K → $39K
SE 2021-0150 Settlement Lewis 2022 $44K → $30K
SE 2010-534M Settlement Lewis 2012 $24K → $17K
SE 2010-134M Settlement Gill 2014 $19K → $15K
SE 2022-0197 Settlement Paez 2024 $10K → $10K
VA 20020001M Settlement Weisberger 2002 $10K → $5K
Source: FMSHRC civil penalty dockets and decisions (public record), updated weekly.

Top causes

Incident timeline

2026
1
2025
1
2024
2
2023
4
2022
3
2021
8
2020
7 (1f)
2019
6
2018
7
2017
6
2016
15
2015
10
2014
10
2013
3
2012
9
2011
6
2010
4
2009
7
2008
4
2007
11
2006
10
2005
10
2004
12
2003
6
2002
8
2001
1
2000
10 (1f)
1999
13
1998
2

Mines on record

Fatalities under this operator

2 recorded
July 24, 2020 GA · Metal/Non-Metal miner, nec Fatality · MACHINERY
Carmeuse L&S · Caught in, under or between a moving and a stationary object

While loading a face on level 3, NW2, the man basket of the powder truck raised up into the roof of the mine causing a fatal incident. The accident is still under investigation by the operator and the Mine Safety and Health Administration.

January 26, 2000 VA · Metal/Non-Metal laborer, blacksmith, bull gang, parts runner, roustabout, pick-up man, pitman Fatality · POWERED HAULAGE
O-N Minerals (Chemstone Company) · Caught in, under or between a moving and a stationary object

EMPLOYEE WAS ATTEMPTING TO REMOVE STONE BUILDUP FROM UNDER SHAFT KILN CARRIAGE COUNTER WEIGHT. HE CLIMBED OVER A GUARD INTO RESTRICTED AREA WHERE THE WEIGHT WAS LOCATED ONLY INCHES OVER HIS HE AD. THE WEIGHT MADE ITS SCHEDULED DESCENT AND EE WAS TRAPPED UNDER IT.

For insurers, brokers, and safety consultants

Where O-N Minerals (Chemstone Company) stands on silica, penalties, and injury rate

MSHA's standard limits respirable silica to 50 micrograms per cubic metre, but MSHA publishes dust and quartz as separate files and never the silica figure itself. We derive it per sample, score it against the limit, and set the operator's injury rate against a benchmark built from the full MSHA operator record. With the 26-year penalty trail, contest posture, and fatality history. Delivered as a PDF with the underlying data as CSV.

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