Twin Underground has $270K in proposed MSHA penalties and $424 outstanding across 9 contested dockets, plus health sampling and the full incident record.
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Fatalities
0
Total incidents
11
Years on record
2013–2026
Latest incident
Aug 2026
Compliance record
MSHA citations since 2011
132
citations
13
significant & substantial
$269,650
proposed penalties
$144,031
paid to date
53% of proposed penalties paid to date, a $125,619 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.
132 citations across 1,669 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: 2022-09-16.
On record since 2022.
Source: MSHA imminent-danger order records, updated weekly.
Twin Underground has $270K in proposed MSHA penalties and $424 outstanding across 9 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.
$270K
proposed penalties
$144K
current assessed
$144K
paid to date
$424
outstanding
129 assessments are final orders; 9 contested dockets.
Of $241K in penalties contested before the Commission, $80K was upheld in final decisions.
As of the most recent assessment on 2026-04-08.
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.
11citations taken to the federal commission · 8% of citations on record
Settled
8 · 73%
Vacated or withdrawn
3 · 27%
63%
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%
67%
Penalty reduction in decided contests
$241K proposed, $80K 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 2022-11-17.
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: 2026-04-08
17%
of limit-tested samples over the exposure limit
17
samples
12
limit-tested
Most sampled contaminants
Diesel particulate (total carbon)62 over
Quartz, respirable, >1% Qtz9
Respirable dust, <.1mg1
Unlisted Particulate, respirable, <1% Qtz1
Show the individual readings (29)
Date
Contaminant
Concentration
Limit
Conc / limit
Occupation
2017-11-15
TC @ 160
246
160
1.54
Mucking Mach. Operator
2013-03-26
EC @ 160
196
160
1.23
Roof Bolter, Rock
2013-03-26
TC @ 160
235
160
1.47
Roof Bolter, Rock
2026-04-08
Quartz, respirable, >1% Qtz
0.88
1.64
0.54
Scoop-Tram Operator
2026-04-08
Quartz, respirable, >1% Qtz
0.47
1.14
0.41
Truck Driver
2019-10-01
EC @ 160
0
160
0.00
Complete Load-Haul-Dump
2019-10-01
TC from EC @ 160
0
160
0.00
Complete Load-Haul-Dump
2019-10-01
Quartz, respirable, >1% Qtz
0.24
Truck Driver
2019-10-01
Quartz, respirable, >1% Qtz
0.26
Laborer, Bullgang
2019-10-01
TC @ 160
0
160
0.00
Truck Driver
2019-10-01
EC @ 160
0
160
0.00
Truck Driver
2019-10-01
TC from EC @ 160
0
160
0.00
Truck Driver
2019-10-01
TC @ 160
32
160
0.20
Complete Load-Haul-Dump
2019-08-17
Quartz, respirable, >1% Qtz
0.5
1.45
0.34
Truck Driver
2019-08-17
Quartz, respirable, >1% Qtz
0.37
Truck Driver
2019-08-17
TC from EC @ 160
0
160
0.00
Front-end Loader Operator
2019-08-17
EC @ 160
40
160
0.25
Front-end Loader Operator
2019-08-17
TC @ 160
53
160
0.33
Front-end Loader Operator
2017-11-15
EC @ 160
104
160
0.65
Mucking Mach. Operator
2017-11-15
TC from EC @ 160
139
160
0.87
Mucking Mach. Operator
2017-11-15
Quartz, respirable, >1% Qtz
0.65
1.41
0.46
Mucking Mach. Operator
2017-11-15
Quartz, respirable, >1% Qtz
0.41
1.22
0.34
Truck Driver
2016-03-08
Respirable dust, <.1mg
0
Mechanic
2016-03-08
Unlisted Particulate, respirable, <1% Qtz
0.62
Roof Bolter, Rock
2013-04-30
TC from EC @ 160
0
160
0.00
Shotcrete/Gunite Man
2013-04-30
TC @ 160
94
160
0.59
Shotcrete/Gunite Man
2013-04-30
EC @ 160
71
160
0.44
Shotcrete/Gunite Man
2013-03-26
Quartz, respirable, >1% Qtz
1.21
2.31
0.52
Mucking Mach. Operator
2013-03-26
TC from EC @ 160
0
160
0.00
Roof Bolter, Rock
Area samples (mill and shop air)
Last sampled: 2017-11-15, 8 years ago
1
samples
Show the individual readings (3)
Date
Contaminant
Concentration
Limit
Conc / limit
Area sampled
2017-11-15
TC from EC @ 160
0
UG TRAVEL/HAULAGE
2017-11-15
EC @ 160
203
UG TRAVEL/HAULAGE
2017-11-15
TC @ 160
271
UG TRAVEL/HAULAGE
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.
Twin Underground recorded 0.00 reportable injury cases per 100 full-time workers in 2023.
Injury rate, 2023
ⓘ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
No reportable injury cases in any year shown. Employee-hours were reported in each of those years, so these are true zeros rather than missing data. Citations, listed in the compliance record above, are inspector-found violations and are counted separately from worker injuries.
Below average. The US metal and nonmetal mining average was 1.78 and the all-US-mining average was 2.10 cases per 100 workers.
In Nevada, metal and nonmetal mining averaged 1.10 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
2023 *
0.00
0.00
0.000
2022 *
0.00
0.00
0.000
2021 *
0.00
0.00
0.000
2020 *
0.00
0.00
0.000
2019 *
0.00
0.00
0.000
2018 *
0.00
0.00
0.000
2017 *
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
1
2025
2
2024
9
2023
23
2022
24
2021
18
2020
16
2019
24
2018
26
2017
13
2016
5
2014
2
2013
5
2012
8
2011
11
Source: MSHA quarterly employment and production, updated weekly.
Twin Underground sits in Humboldt County, Nevada, where the Census mining category is 20.1% 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.
Humboldt County, Nevada · Population 17,299
20.1%
Mining share of county employment
$79,946
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
Nevada Gold Mines LLC · Caught in, under or between a moving and a stationary object
EE was loosening bolt on pot head when the wrench slipped and pinched their left index finger between the wrench and the pot head. EE reported incident on DOI. Seen at clinic 8/7, diagnosed with left index finger fracture, referred to orthopedics. Released to restrictions which are being accommodated.
Miners were attempting to remove an old pump discharge pipe. The upstream valve had been isolated. While loosening the 4-inch Victaulic fitting, the pipe separated due to tension within the line, causing one of the pipes to swing toward the employee, striking EE in the right lower chest.
Employee was changing out steel on a bolter when they lost footing and fell back. Employee denied medical attention initially. November they requested to see a doctor, employee was taken to an urgent care and referred to a specialist. Employee was put on RD by the specialist pending surgery.
June 15, 2021NV · Metal/Non-Metallaborer, bull gang, faceman, parts runner, roustabout, roof trimmer/scalerSLIP OR FALL OF PERSON
Employee lost consciousness due to a medical incident not related to work. EE fell forward and struck EE's face on a bolt plate causing a laceration to EE's cheek.
A ground fall occurred post blast at Vista Underground-Turquoise Ridge at the 1N3960 level. No ventilation or access was restricted. No injuries sustained.
Employee was driving down the decline. The employee passed another operator and applied the engine break through the turn and the front left bed corner struck the pillar rib of the muckbay causing the employees face to make contact with the truck radio resulting in a laceration on right cheek and nostril.
On April 24 a back shot was taken on 112 stope. Upon inspection it was noticed that the back had broken past the designed stope towards the access. SMD notified the Vista Underground engineering team. Chief Engineer Ben Gunn inspected the site and determined the rock had broken beyond primary ground support and MSHA was notified.
Employee was riding in the back of a tractor. The tractor hit a hole and the employee bounced up and back down striking the bottom of their foot on a hose that was on the floor. Their foot flexed up against the metatarsal boot causing a fracture.
Miner had a piece of rock come off approximately 6ft from the r- rib hitting the right tip of EE's middle finger. The injury resulted in 5 stitches at the end of EE's finger.