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.
Rate withheld: 960 inspection hours is too few for a stable rate. A minimum of 1,000 inspection hours is required.
Source: MSHA inspections data, updated weekly.
Diablo #4 has $6K in proposed MSHA penalties and $0 outstanding across 4 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.
$6K
proposed penalties
$5K
current assessed
$5K
paid to date
$0
outstanding
25 assessments are final orders; 4 contested dockets.
Of $3K in penalties contested before the Commission, $3K was upheld in final decisions.
As of the most recent assessment on 2024-11-25.
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.
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.
12citations taken to the federal commission · 46% of citations on record
Settled
12 · 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 Vacated and withdrawn citations, and settlements that removed the designation, count against.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 8 decided S&S contests · industry: 79%
16%
Penalty reduction in decided contests
$3K proposed, $3K 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 A dismissed or defaulted contest leaves the citation standing as issued; a vacated or withdrawn citation is removed from the violation record.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 2025-03-04.
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.
MSHA sampling at Diablo #4 shows 99% of 85 respirable coal dust samples met the 1.5 mg/m3 standard.
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.
Respirable coal dust
ⓘRespirable coal dust and silica figures cover coal facilities. Dust compliance is measured against the current 1.5 mg/m3 standard; samples predating the 2014 standard are included, so compliance rates are a coarse historical signal.
Last sampled: 2025-03-21
99%
within 1.5 mg/m3
85
samples
1.52
dust max (mg/m3)
0
over MSHA ECV
ⓘThe excessive concentration value (ECV) is MSHA's own per-sample enforcement threshold, which builds in measurement uncertainty; a sample over its ECV can trigger a citation. The count covers only samples MSHA assigned an ECV.
45 samples taken by MSHA inspectors, 40 by the operator.
Noise
ⓘThe share counts noise samples whose measured dose exceeded the 90 dBA permissible exposure limit. It describes the sampled workplace, not what reached the miner's ear: hearing conservation programs and the hearing protection worn during the shift are recorded separately and are not reflected here.
Health sampling trend
ⓘ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.
Respirable coal dust by year
ⓘRespirable coal dust and silica figures cover coal facilities. Dust compliance is measured against the current 1.5 mg/m3 standard; samples predating the 2014 standard are included, so compliance rates are a coarse historical signal.
Diablo #4 recorded 2.51 reportable injury cases per 100 full-time workers in 2024.
Injury rate, 2024
ⓘ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.
2.51
total case rate
2.51
days-away rate
0.000
fatality rate
Below average. The US coal mining average was 3.16 and the all-US-mining average was 2.08 cases per 100 workers.
In Kentucky, coal mining averaged 4.17 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
2024 *
2.51
2.51
0.000
2023 *
0.00
0.00
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
ⓘCoal production is reported quarterly and lags the current period; the most recent quarters may be incomplete.
Year
Employees
Coal produced (tons)
2026
0
2025
9
18,490
2024
32
134,532
2023
32
153,817
2022
23
47,814
Source: MSHA quarterly employment and production, updated weekly.
Diablo #4 sits in Breathitt County, Kentucky, where the Census mining category is 2.3% 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.
Breathitt County, Kentucky · Population 13,438
2.3%
Mining share of county employment
$41,101
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
0
0
0
2026 Q1
0
0
0
2025 Q4
0
0
0
2025 Q3
68
0
0
0.0
2025 Q2
2,203
0
0
0.0
2025 Q1
12,551
0
0
0.0
2024 Q4
18,757
5
2
266.6
2024 Q3
19,770
4
2
202.3
Show 8 earlier quartersHide earlier quarters
Quarter
Hours worked
Citations
S&S
Per 1M hrs
2024 Q2
20,781
4
2
192.5
2024 Q1
20,274
0
0
0.0
2023 Q4
17,241
4
2
232.0
2023 Q3
16,075
0
0
0.0
2023 Q2
21,006
2
1
95.2
2023 Q1
20,156
0
0
0.0
2022 Q4
18,163
5
2
275.3
2022 Q3
1,625
1
0
615.4
No fatalities recorded at this mine.
Reportable incidents
1 on file
2024 · 1 incident
October 24, 2024KY · Coalbulldozer operator, universal operator, heavy equipment operator, operating engineerSLIP OR FALL OF PERSON
Employee was running a drill when EE began feeling weak. EE feel into the controls of the drill while standing. EE drove self to the local Hazard ARH Hospital and was then transferred to UK in Lexington, KY.