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: 599 inspection hours is too few for a stable rate. A minimum of 1,000 inspection hours is required.
Source: MSHA inspections data, updated weekly.
Portable Unit #2 has $21K in proposed MSHA penalties and $0 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.
$21K
proposed penalties
$21K
current assessed
$21K
paid to date
$0
outstanding
89 assessments are final orders; 1 contested dockets.
Of $125 in penalties contested before the Commission, $125 was upheld in final decisions.
As of the most recent assessment on 2026-02-26.
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.
1citations taken to the federal commission · 1% of citations on record
Settled
1 · 100%
0%
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 Vacated and withdrawn citations, and settlements that removed the designation, count against.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
$125 proposed, $125 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 A dismissed or defaulted contest leaves the citation standing as issued; a vacated or withdrawn citation is removed from the violation record.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 2021-06-30.
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: 2018-04-25, 8 years ago
20%
of limit-tested samples over the exposure limit
10
samples
5
limit-tested
Most sampled contaminants
Quartz, respirable, >1% Qtz61 over
Respirable dust, <.1mg4
Show the individual readings (10)
Date
Contaminant
Concentration
Limit
Conc / limit
Occupation
2003-02-26
Quartz, respirable, >1% Qtz
2.19
1.83
1.20
Front-end Loader Operator
2018-04-25
Quartz, respirable, >1% Qtz
0.13
Front-end Loader Operator
2018-04-25
Respirable dust, <.1mg
0
Cleanup Man
2013-05-29
Respirable dust, <.1mg
0
Bobcat Operator
2013-05-29
Respirable dust, <.1mg
0
Front-end Loader Operator
2010-01-13
Quartz, respirable, >1% Qtz
0.29
1.73
0.17
Front-end Loader Operator
2010-01-13
Quartz, respirable, >1% Qtz
0.48
1.65
0.29
Crusher Oper/Worker
2004-12-15
Quartz, respirable, >1% Qtz
0.38
1.53
0.25
Crusher Oper/Worker
2004-12-15
Respirable dust, <.1mg
0
Supervisor, Co. Official
2003-02-26
Quartz, respirable, >1% Qtz
0.57
2.09
0.27
Crusher Oper/Worker
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.
Source: MSHA controller and operator history, updated weekly.
Workforce and production
Year
Employees
2026
3
2025
3
2024
3
2023
2
2022
2
2021
3
2020
3
2019
2
2018
2
2017
3
2016
3
2015
3
2014
3
2013
3
2012
3
2011
3
2010
4
2009
4
2008
4
2007
4
2006
3
2005
3
2004
2
2003
2
2002
2
2001
2
2000
3
Source: MSHA quarterly employment and production, updated weekly.
Portable Unit #2 sits in Rock County, Wisconsin, where the Census mining category is 0.1% 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.
Rock County, Wisconsin · Population 163,944
0.1%
Mining share of county employment
$74,390
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
Bjoin Limestone Inc · Caught in, under or between a moving and a stationary object
A boulder was stuck in the jaw. Employee shut down the power source, locked out, put on his safety harness, climbed up on platform, tied himself off removed handrail. He then attempted to put on the chain to extract the boulder. Realized the jaw was not in the resting position, jaw rolled over and pinched his finger.