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: 87 inspection hours is too few for a stable rate. A minimum of 1,000 inspection hours is required.
Source: MSHA inspections data, updated weekly.
KEYSTONE MILL has $155 in proposed MSHA penalties and $0 outstanding across 0 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.
$155
proposed penalties
$155
current assessed
$155
paid to date
$0
outstanding
2 assessments are final orders; 0 contested dockets.
As of the most recent assessment on 2007-09-11.
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 controller and operator history, updated weekly.
Workforce and production
Year
Employees
2009
2
2008
2
2007
2
2006
2
2005
2
2004
2
2003
2
2002
2
2001
2
2000
2
Source: MSHA quarterly employment and production, updated weekly.
KEYSTONE MILL sits in Tuolumne County, California, where the Census mining category is 0.3% 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.
Tuolumne County, California · Population 54,873
0.3%
Mining share of county employment
$72,259
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
2009 Q3
3
0
0
0.0
2009 Q2
11
0
0
0.0
2009 Q1
12
0
0
0.0
2008 Q4
17
0
0
0.0
2008 Q3
33
0
0
0.0
2008 Q2
17
0
0
0.0
2008 Q1
21
0
0
0.0
2007 Q4
19
0
0
0.0
Show 30 earlier quartersHide earlier quarters
Quarter
Hours worked
Citations
S&S
Per 1M hrs
2007 Q3
14
1
0
71428.6
2007 Q2
17
0
0
0.0
2007 Q1
23
0
0
0.0
2006 Q4
21
0
0
0.0
2006 Q3
13
0
0
0.0
2006 Q2
30
0
0
0.0
2006 Q1
6
0
0
0.0
2005 Q4
3
0
0
0.0
2005 Q3
4
0
0
0.0
2005 Q2
3
0
0
0.0
2005 Q1
3
0
0
0.0
2004 Q4
10
0
0
0.0
2004 Q3
20
0
0
0.0
2004 Q2
17
0
0
0.0
2004 Q1
22
0
0
0.0
2003 Q4
18
1
0
55555.6
2003 Q3
23
0
0
0.0
2003 Q2
25
0
0
0.0
2003 Q1
35
0
0
0.0
2002 Q3
30
0
0
0.0
2002 Q2
60
0
0
0.0
2002 Q1
100
0
0
0.0
2001 Q4
90
0
0
0.0
2001 Q3
132
0
0
0.0
2001 Q2
165
0
0
0.0
2001 Q1
175
0
0
0.0
2000 Q4
160
1
0
6250.0
2000 Q3
178
0
0
0.0
2000 Q2
155
0
0
0.0
2000 Q1
157
0
0
0.0
No fatalities recorded at this mine.
Reportable incidents
3 on file
1993 · 1 incident
January 18, 1993CA · Metal/Non-Metalprep plant foreman, supervisor, mill plant supervisor, kiln supervisorSLIP OR FALL OF PERSON