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.
108 citations across 1,529 inspection hours.
Source: MSHA inspections data, updated weekly.
Corona Plant has $15K in proposed MSHA penalties and $0 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.
$15K
proposed penalties
$13K
current assessed
$13K
paid to date
$0
outstanding
106 assessments are final orders; 2 contested dockets.
Of $7K in penalties contested before the Commission, $1K was upheld in final decisions.
As of the most recent assessment on 2026-02-04.
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.
4citations taken to the federal commission · 4% of citations on record
Settled
2 · 50%
Vacated or withdrawn
2 · 50%
50%
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 Vacated and withdrawn citations, and settlements that removed the designation, count against.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 4 decided S&S contests · industry: 79%
86%
Penalty reduction in decided contests
$7K proposed, $1K 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 A dismissed or defaulted contest leaves the citation standing as issued; a vacated or withdrawn citation is removed from the violation record.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 2018-03-18.
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: 2023-09-07
0%
of limit-tested samples over the exposure limit
21
samples
11
limit-tested
Most sampled contaminants
Quartz, respirable, >1% Qtz11
Respirable dust, <.1mg10
Show the individual readings (21)
Date
Contaminant
Concentration
Limit
Conc / limit
Occupation
2023-09-07
Respirable dust, <.1mg
0
Laborer, Bullgang
2021-12-02
Quartz, respirable, >1% Qtz
0.25
0.76
0.33
Dry Screen Plant Operator
2018-01-03
Quartz, respirable, >1% Qtz
0.25
1.82
0.14
Cleanup Man
2018-01-03
Quartz, respirable, >1% Qtz
0.24
1.08
0.22
Cleanup Man
2013-02-06
Respirable dust, <.1mg
0
Crusher Oper/Worker
2013-02-06
Quartz, respirable, >1% Qtz
0.27
1.14
0.24
Dry Screen Plant Operator
2013-02-06
Quartz, respirable, >1% Qtz
0.12
1
0.12
Laborer, Bullgang
2010-02-03
Respirable dust, <.1mg
0
Road Grader Operator
2010-02-03
Quartz, respirable, >1% Qtz
0.14
0.7
0.20
Crusher Oper/Worker
2010-02-03
Quartz, respirable, >1% Qtz
0.24
0.76
0.32
Laborer, Bullgang
2010-02-03
Quartz, respirable, >1% Qtz
0.42
0.72
0.58
Laborer, Bullgang
2005-04-13
Respirable dust, <.1mg
0
Oiler, Greaser
2005-04-13
Quartz, respirable, >1% Qtz
0.27
0.63
0.43
Crusher Oper/Worker
2005-04-13
Quartz, respirable, >1% Qtz
0.55
0.61
0.90
Belt Crew
2005-04-13
Respirable dust, <.1mg
0
Front-end Loader Operator
2005-04-13
Respirable dust, <.1mg
0
Front-end Loader Operator
2005-04-12
Respirable dust, <.1mg
0
Shovel Operator
2005-04-12
Quartz, respirable, >1% Qtz
0.22
1.23
0.18
Truck Driver
2002-08-14
Respirable dust, <.1mg
0
Front-end Loader Operator
2002-08-14
Respirable dust, <.1mg
0
Crusher Oper/Worker
2002-08-14
Respirable dust, <.1mg
0
Cleanup Man
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.
Corona Plant recorded 0.00 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.
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 1.65 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 *
0.00
0.00
0.000
2024 *
0.00
0.00
0.000
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
* 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
42
2025
42
2024
42
2023
31
2022
38
2021
40
2020
41
2019
42
2018
40
2017
35
2016
36
2015
35
2014
32
2013
29
2012
30
2011
31
2010
32
2009
40
2008
44
2007
37
2006
31
2005
31
2004
27
2003
27
2002
27
2001
27
2000
17
Source: MSHA quarterly employment and production, updated weekly.
Corona Plant sits in Riverside County, California, 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.
Riverside County, California · Population 2,449,909
0.1%
Mining share of county employment
$89,672
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
Independent hauler was experiencing symptoms of a heart attack and called EMS. EMS transported the hauler to the hospital. The MSHA investigator requested an MSHA 7000-1 be completed.
2014 · 1 incident
November 4, 2014CA · Metal/Non-Metalmaintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service techFIRE
CalMat Co · Contact with hot objects or substances
The employee sustained 2nd degree burns. The employee was using a cutting torch to cut a one inch thick steel plate on a fabrication table. The slag from the cutting bounced off of the table and ignited the employee's shirt resulting in 2nd degree burns to the left side of the abdomen. The employee was placed restricted duty on 11/5/14 which is being accommodated.
On 5/25/09 A trespasser/Non-Employee was fatally injured from an apparent fall from elevation. The trespasser/Non-Employee's death occurred in route to the hospital.
2008 · 1 incident
September 2, 2008CA · Metal/Non-Metalmaintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service techHANDTOOLS (NONPOWERED)
CalMat Co · Struck by... (Not Elsewhere Classified)
The employee went to the company clinic on 9/3/08 and was placed on restricted duty. A porta-power disconnect fitting came apart when pressurised and struck employee on his safety glasses, resulting in a corneal abrasion and contusion to R-eye.
2006 · 1 incident
June 2, 2006CA · Metal/Non-Metalbeltman, conveyor man, conveyor belt worker, mobile bridge carrierman, feeder operator, conveyor riderHANDLING OF MATERIALS
CalMat Co · Over-exertion in pulling or pushing objects
The employee went to see the company doctor on 6/7/2006 and was placed on restricted duty. The employee strained his lower back while lifting and carrying buckets during crusher sampling
2004 · 1 incident
August 20, 2004CA · Metal/Non-Metalmaintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service techHANDLING OF MATERIALS
CalMat Co · Over-exertion (Not Elsewhere Classified)
Employee went to see company doctor on 8/21/04 and was placed on restricted duty. Employee was placing various tools in a pile, wrench, screwdrivers, etc. and strained his lower back.
WHILE CUTTING BOLTS FROM DISCHARGE LIP WITH OXY-ACETYLEN TORCH. SLAG FELL ONTO CHUTE LINER CAUSING FIRE WHICH RESULTED IN PROPERTY DAMAGE.
May 8, 2003CA · Metal/Non-Metalblaster, shooter, shotfirer, explosive worker, powder gang/monkeyHANDLING OF MATERIALS
CalMat Co · Over-exertion (Not Elsewhere Classified)
EMULSION HOSE BECAME LODGED IN BOREHOLE. EE JERKED ON HOSE TO FREE IT AND HEARD POP IN HIS LOWER BACK.
2002 · 1 incident
March 13, 2002CA · Metal/Non-Metalbeltman, conveyor man, conveyor belt worker, mobile bridge carrierman, feeder operator, conveyor riderHANDTOOLS (NONPOWERED)
CalMat Co · Struck by... (Not Elsewhere Classified)
EE WAS USING A 20# SLEDGEHAMMER & KNOCKER WRENCH TO TIGHTEN JAW BOLTS; THE HAMMER WAS DEFLECTED CAUSING IT TO MISS THE WRENCH STRIKING FINGER CAUSING A FRACTURE & LACERATION TO L-INDEX FINGER. EE WENT TO SEE COMPANY DR ON 3/13/02 & WAS PLACED ON RESTRICTED DUTY.
2001 · 2 incidents
September 29, 2001CA · Metal/Non-Metalwelder (shop)MACHINERY
EMPLOYEE WENT TO CLINIC ON 9/29/01 AND WAS RETURNED TO FULL DUTY AND RECEIVED PRESCRIPTION AND MEDICATION. EMPLOYEE WAS WELDING ON EXCAVATOR BUCKET WHEN HE RECEIVED FLASH BURN TO BOTH EYES.
June 21, 2001CA · Metal/Non-Metalmaintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service techHANDTOOLS (NONPOWERED)
CalMat Co · Struck by... (Not Elsewhere Classified)
EMPLOYEE WAS USING A KNIFE, CUTTING LEG OF SCREEN PANEL, PULLING KNIFE TOWARDS BODY AND KNIFE CONTACTED LEFT WRIST. EMPLOYEE WENT TO SEE DOCTOR ON 6-22-01, RECEIVED STITCHES AND WAS PLACED ON RESTRICTED DUTY.
EE CUTTING METAL WITH A TORCH WHEN HOSE CAME OFF CUASING BURNS TO LOWER LEFT ARM & ABDOMEN AREA
August 14, 1998CA · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorHANDTOOLS (NONPOWERED)
Calmat Company · Struck by... (Not Elsewhere Classified)
EE WAS CUTTING TAPE OFF BOARD HOLDING BOARD WITH LEFT HAND AND HOLDING KNIFE WITH RIGHT HAND. KNIFE SLIPED, POINT OF KNIFE ENTERED LEFT HAND BETWEEN INDEX AND MIDDLE KNUCKLE.
April 10, 1998CA · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorSLIP OR FALL OF PERSON
Calmat Company · Over-exertion (Not Elsewhere Classified)
EE WAS TRYING TO REMOVE LODGED ROCK FROM CONVEYOR WHEN HE SLIPPED AND SPRAINED HIS RIGHT ARM.
1997 · 2 incidents
November 19, 1997CA · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorMACHINERY
Calmat Company · Absorption of radiations, caustics, toxic and noxious substances
EE WAS CHOPPING WEEDS AROUND EXPLOSIVE MAGAZIE WHEN A BEE STUNG HIS RIGHT LOWER ARM/
1996 · 3 incidents
November 21, 1996CA · Metal/Non-Metalclerk, timekeeper, office worker, director of salesHANDLING OF MATERIALS
Calmat Company · Caught in, under or between a moving and a stationary object
EMPLOYEE WAS OPENING A HEAVY WOODEN DOOR ON A STORAGE SHED AND HIS FINGER WAS CAUGHT BETWEEN THE DOOR AND A STEEL DOOR HASP (LOCK). THE WEIGHT OF THE DOOR CAUSED THE HASP TO PINCH HIS FINGER.
EMPLOYEE WAS REMMOVING A ROCK A B-1 (OVERSIZE), THE CHAIN COME-A-LONG (3/4TON) CAME LOOSE LANDING ON EMPLOYEE'S FINGER CUTTING IT.
February 3, 1995CA · Metal/Non-Metalwarehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operatorHANDLING OF MATERIALS
Calmat Company · Struck by... (Not Elsewhere Classified)
WHILE ATTEMPTING TO REMOVE ROCK FROM JAMMED CHUTE, A ROCK BECAME LOOSE DROPPING FROM THE FEEDER AREA ONTO EE'S LEFT INDEX FINGER, CUTTING IT.
1994 · 3 incidents
October 25, 1994CA · Metal/Non-Metalmaintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service techMACHINERY
Calmat Company · Struck by... (Not Elsewhere Classified)
EE WAS REMOVING WEAR SEGMENTS FROM 988B BUCKET WITH A 1" IMPACT AIR GUN. THE PLOW BOLT FELL OUT OF KEYED SLOT AND STARTED SPINING WHICH CUT HIS ARM (WRIST).
EE WAS HOLDING A STEEL PLATE IN PLACE WHILE ANOTHER EE WAS WELDING, HIS ELBOW HIT THE WELDING TORCH CAUSING OXYGEN TO ESCAPE FROM THE WELDING SPARKS. THIS CAUSED THE TORCH TO BURN HIS LEFT ARM .
September 8, 1994CA · Metal/Non-Metalprep plant foreman, supervisor, mill plant supervisor, kiln supervisorSLIP OR FALL OF PERSON
EMPLOYEE WAS CHECKING OUT A BROKEN SHAFT ON A FINISH SCREEN. WHEN HE CRAWLED OUT HE SLIPPED ON ROCKS ON BELT AND CAUGHT HIMSELF ON THE SCREEN WITH HIS LEFT ARM TO KEEP HIMSELF FROM FALLING AND PULLED MUSCLES IN HIS LEFT ARM.
1993 · 2 incidents
August 28, 1993CA · Metal/Non-Metalmaintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service techHANDTOOLS (NONPOWERED)
NO INJURIES. BRUSH FIRE OF UNKNOWN ORIGIN STARTED ON COMPANY PROPERTY. FIRE DEPARTMENT RESPONDED. NO ACCESS TO FIRE AREA. FIRE ALLOWED TO BURN ITSELF OUT AFTER FIRE BREAKS WERE CUT WITH COMPAN Y BULLDOZER.
1991 · 1 incident
November 15, 1991CA · Metal/Non-Metaldrill operatorMACHINERY