Superior - Twin Oaks has $66K in proposed MSHA penalties and $20K outstanding across 2 contested dockets, plus health sampling and the full incident record.
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Fatalities
0
Total incidents
8
Years on record
2005–2025
Latest incident
Apr 2025
Compliance record
MSHA citations since 2002
194
citations
59
significant & substantial
$65,552
proposed penalties
$45,269
paid to date
69% of proposed penalties paid to date, a $20,283 gap.
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.
194 citations across 1,066 inspection hours.
Source: MSHA inspections data, updated weekly.
Imminent-danger orders
ⓘA Section 107(a) order removes miners from an area when an inspector finds an imminent danger. Each order is lifted once the condition is corrected, so this counts orders issued, not orders now in effect.
1
Section 107(a) orders
Most recent order: 2023-03-22.
On record since 2023.
Source: MSHA imminent-danger order records, updated weekly.
Superior - Twin Oaks has $66K in proposed MSHA penalties and $20K outstanding across 2 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.
$66K
proposed penalties
$66K
current assessed
$45K
paid to date
$20K
outstanding
190 assessments are final orders; 2 contested dockets.
Of $4K in penalties contested before the Commission, $4K was upheld in final decisions.
As of the most recent assessment on 2025-06-25.
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.
6citations taken to the federal commission · 3% of citations on record
Settled
5 · 83%
Stood as issued
1 · 17%
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%
0%
Penalty reduction in decided contests
$4K proposed, $4K 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 2009-02-09.
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: 2025-01-23
20%
of limit-tested samples over the exposure limit
27
samples
15
limit-tested
Most sampled contaminants
Quartz, respirable, >1% Qtz153 over
Respirable dust, <.1mg11
Unlisted Particulate, respirable, <1% Qtz1
Show the individual readings (27)
Date
Contaminant
Concentration
Limit
Conc / limit
Occupation
2013-12-18
Quartz, respirable, >1% Qtz
1.01
0.66
1.53
Laborer, Bullgang
2005-12-21
Quartz, respirable, >1% Qtz
1.22
0.79
1.54
Cleanup Man
2003-11-25
Quartz, respirable, >1% Qtz
1.32
0.68
1.94
Crusher Oper/Worker
2025-01-23
Respirable dust, <.1mg
0
Front-end Loader Operator
2023-11-29
Respirable dust, <.1mg
0
Laborer, Bullgang
2021-05-06
Quartz, respirable, >1% Qtz
0.51
0.83
0.61
Crusher Oper/Worker
2021-05-06
Quartz, respirable, >1% Qtz
0.26
0.86
0.30
Dry Screen Plant Operator
2020-03-03
Respirable dust, <.1mg
0
Crusher Oper/Worker
2017-06-01
Quartz, respirable, >1% Qtz
0.46
0.73
0.63
Crusher Oper/Worker
2017-06-01
Respirable dust, <.1mg
0
Washer Operator
2017-06-01
Quartz, respirable, >1% Qtz
0.39
0.88
0.44
Laborer, Bullgang
2017-06-01
Respirable dust, <.1mg
0
Drill Operator, Rotary
2014-03-05
Quartz, respirable, >1% Qtz
0.16
1.24
0.13
Laborer, Bullgang
2013-12-18
Quartz, respirable, >1% Qtz
0.41
2.86
0.14
Front-end Loader Operator
2009-04-01
Quartz, respirable, >1% Qtz
0.34
0.88
0.39
Laborer, Bullgang
2009-04-01
Quartz, respirable, >1% Qtz
0.31
0.91
0.34
Crusher Oper/Worker
2006-03-01
Respirable dust, <.1mg
0
Laborer, Bullgang
2005-12-21
Quartz, respirable, >1% Qtz
0.14
0.78
0.18
Jackhammer Operator
2005-12-21
Quartz, respirable, >1% Qtz
0.36
1.25
0.29
Crusher Oper/Worker
2005-04-19
Unlisted Particulate, respirable, <1% Qtz
0.49
Bulldozer Operator
2005-04-19
Respirable dust, <.1mg
0
Crusher Oper/Worker
2005-04-19
Respirable dust, <.1mg
0
Laborer, Bullgang
2005-04-19
Respirable dust, <.1mg
0
Front-end Loader Operator
2004-04-06
Quartz, respirable, >1% Qtz
1.22
2.03
0.60
Crusher Oper/Worker
2004-04-06
Respirable dust, <.1mg
0
Front-end Loader Operator
2004-04-06
Respirable dust, <.1mg
0
Front-end Loader Operator
2003-11-25
Quartz, respirable, >1% Qtz
0.38
0.94
0.40
Front-end Loader 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.
Superior - Twin Oaks recorded 9.44 reportable injury cases per 100 full-time workers in 2025.
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.
9.44
total case rate
9.44
days-away rate
0.000
fatality rate
Above average. The US metal and nonmetal mining average was 1.65 and the all-US-mining average was 1.97 cases per 100 workers.
In California, metal and nonmetal mining averaged 1.42 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
2025 *
9.44
9.44
0.000
2024 *
7.76
7.76
0.000
2023 *
0.00
0.00
0.000
2022 *
7.96
7.96
0.000
2021 *
7.45
7.45
0.000
2020 *
0.00
0.00
0.000
2019 *
0.00
0.00
0.000
2018 *
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
Year
Employees
2026
19
2025
11
2024
11
2023
11
2022
10
2021
11
2020
11
2019
13
2018
12
2017
10
2016
8
2015
9
2014
9
2013
9
2012
9
2011
8
2010
6
2009
10
2008
10
2007
13
2006
14
2005
15
2004
11
2003
10
2002
9
Source: MSHA quarterly employment and production, updated weekly.
Superior - Twin Oaks sits in San Diego County, California, where the Census mining category is 0.0% 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.
San Diego County, California · Population 3,282,782
0.0%
Mining share of county employment
$102,285
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
6,677
0
0
0.0
2026 Q1
5,377
0
0
0.0
2025 Q4
3,604
0
0
0.0
2025 Q3
4,976
0
0
0.0
2025 Q2
6,576
5
1
760.3
2025 Q1
6,020
1
0
166.1
2024 Q4
6,639
0
0
0.0
2024 Q3
6,209
0
0
0.0
Show 89 earlier quartersHide earlier quarters
Quarter
Hours worked
Citations
S&S
Per 1M hrs
2024 Q2
6,572
0
0
0.0
2024 Q1
6,360
0
0
0.0
2023 Q4
5,513
10
4
1813.9
2023 Q3
5,666
0
0
0.0
2023 Q2
6,404
2
0
312.3
2023 Q1
5,196
5
2
962.3
2022 Q4
6,224
0
0
0.0
2022 Q3
5,975
3
1
502.1
2022 Q2
7,357
0
0
0.0
2022 Q1
5,579
3
2
537.7
2021 Q4
6,660
0
0
0.0
2021 Q3
7,094
0
0
0.0
2021 Q2
6,444
2
0
310.4
2021 Q1
6,646
0
0
0.0
2020 Q4
7,673
4
1
521.3
2020 Q3
7,638
0
0
0.0
2020 Q2
5,619
3
1
533.9
2020 Q1
4,983
3
2
602.0
2019 Q4
6,817
0
0
0.0
2019 Q3
6,666
0
0
0.0
2019 Q2
7,432
1
1
134.6
2019 Q1
5,543
1
0
180.4
2018 Q4
5,926
0
0
0.0
2018 Q3
5,016
0
0
0.0
2018 Q2
7,352
2
0
272.0
2018 Q1
6,598
3
1
454.7
2017 Q4
8,746
0
0
0.0
2017 Q3
6,814
0
0
0.0
2017 Q2
7,355
4
3
543.8
2017 Q1
4,930
0
0
0.0
2016 Q4
5,026
10
2
1989.7
2016 Q3
4,635
0
0
0.0
2016 Q2
4,984
7
2
1404.5
2016 Q1
4,211
6
3
1424.8
2015 Q4
4,655
0
0
0.0
2015 Q3
5,099
6
2
1176.7
2015 Q2
4,625
0
0
0.0
2015 Q1
4,390
0
0
0.0
2014 Q4
4,231
5
3
1181.8
2014 Q3
4,728
0
0
0.0
2014 Q2
5,497
2
2
363.8
2014 Q1
4,591
1
1
217.8
2013 Q4
3,784
1
0
264.3
2013 Q3
5,579
0
0
0.0
2013 Q2
4,225
1
1
236.7
2013 Q1
4,550
0
0
0.0
2012 Q4
3,516
5
2
1422.1
2012 Q3
4,387
2
0
455.9
2012 Q2
3,700
0
0
0.0
2012 Q1
3,716
5
4
1345.5
2011 Q4
3,251
0
0
0.0
2011 Q3
3,775
2
0
529.8
2011 Q2
3,186
0
0
0.0
2011 Q1
2,209
3
0
1358.1
2010 Q4
2,891
0
0
0.0
2010 Q3
3,007
0
0
0.0
2010 Q2
2,653
6
4
2261.6
2010 Q1
2,275
0
0
0.0
2009 Q4
3,230
4
1
1238.4
2009 Q3
3,214
0
0
0.0
2009 Q2
4,162
0
0
0.0
2009 Q1
6,229
3
0
481.6
2008 Q4
4,637
6
1
1293.9
2008 Q3
4,535
0
0
0.0
2008 Q2
5,625
0
0
0.0
2008 Q1
5,225
3
0
574.2
2007 Q4
4,934
1
0
202.7
2007 Q3
6,644
0
0
0.0
2007 Q2
6,357
8
1
1258.5
2007 Q1
6,527
0
0
0.0
2006 Q4
5,531
0
0
0.0
2006 Q3
7,301
4
2
547.9
2006 Q2
6,520
0
0
0.0
2006 Q1
5,670
2
1
352.7
2005 Q4
5,589
3
0
536.8
2005 Q3
7,097
0
0
0.0
2005 Q2
5,886
9
2
1529.1
2005 Q1
5,436
0
0
0.0
2004 Q4
5,412
4
0
739.1
2004 Q3
4,723
1
0
211.7
2004 Q2
5,580
8
1
1433.7
2004 Q1
5,291
0
0
0.0
2003 Q4
5,698
8
3
1404.0
2003 Q3
4,913
0
0
0.0
2003 Q2
5,748
4
1
695.9
2003 Q1
4,627
0
0
0.0
2002 Q4
5,026
4
0
795.9
2002 Q3
4,720
1
1
211.9
2002 Q2
3,878
5
0
1289.3
No fatalities recorded at this mine.
Reportable incidents
8 on file
2025 · 1 incident
April 25, 2025CA · Metal/Non-Metalmaintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service techHANDLING OF MATERIALS
On 6/17/25 employee provided a modified duty work status report from their personal doctor dated 6/12/25. On 4/25/25 employee reported a first aid from pain to their right arm while placing a wear liner into position. Employee self procured medical treatment, was diagnosed with a ruptured bicep, and restricted duty is being accommodated.
2024 · 1 incident
November 21, 2024CA · Metal/Non-Metalfront-end loader, scraper-loader operator, pan operator, payloader, scraper rig operatorSLIP OR FALL OF PERSON
Employee slipped and fell climbing from ladder to the cone crusher, injuring lower back.
2009 · 1 incident
August 18, 2009CA · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorSLIP OR FALL OF PERSON
sprain of hip and thigh due to normal activity, repetitive application of break on loader.
2006 · 1 incident
July 20, 2006CA · Metal/Non-Metalmaintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service techSLIP OR FALL OF PERSON
Employee was operating plant. A rock became lodged in a conveyor belt. Employee used a pry bar and hammer to dislodge rock. Hammer struck pry bar, pry bar struck employee's finger.
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