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: 140 inspection hours is too few for a stable rate. A minimum of 1,000 inspection hours is required.
Source: MSHA inspections data, updated weekly.
Twin Buttes Mine has $2K 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.
$2K
proposed penalties
$2K
current assessed
$2K
paid to date
$0
outstanding
20 assessments are final orders; 1 contested dockets.
Of $108 in penalties contested before the Commission, $100 was upheld in final decisions.
As of the most recent assessment on 2013-03-19.
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 · 5% of citations on record
Settled
1 · 100%
7%
Penalty reduction in decided contests
$108 proposed, $100 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 A dismissed or defaulted contest leaves the citation standing as issued; a vacated or withdrawn citation is removed from the violation record.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 2011-07-19.
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: 2011-09-21, 14 years ago
67%
of limit-tested samples over the exposure limit
3
samples
3
limit-tested
Most sampled contaminants
Quartz, respirable, >1% Qtz32 over
Show the individual readings (3)
Date
Contaminant
Concentration
Limit
Conc / limit
Occupation
2011-09-21
Quartz, respirable, >1% Qtz
1.12
0.97
1.15
Lab Technician
2011-09-21
Quartz, respirable, >1% Qtz
1
0.91
1.10
Lab Technician
2011-09-21
Quartz, respirable, >1% Qtz
0.76
0.86
0.88
Lab Technician
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
2013
3
2012
3
2011
4
2010
4
Source: MSHA quarterly employment and production, updated weekly.
Twin Buttes Mine sits in Pima County, Arizona, where the Census mining category is 0.6% 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.
Pima County, Arizona · Population 1,049,947
0.6%
Mining share of county employment
$67,929
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
Employee was supervising the installation of forms for the hearth being worked on when a worker lifted the form, lost his grip and the form fell against the left hand of employee.
2011 · 2 incidents
August 26, 2011AZ · Metal/Non-Metalassayer, geologist, metallurgist, engineer, engineer managementHANDLING OF MATERIALS
Employee states that he had just parked the water truck and got out to set the cones down, then hooked the water hose, and as he walked away he passed out and fell to the ground landing face forward.
Related mines
Other mines operated by Freeport-McMoRan Sierrita Inc.