Mining Incidents

Riverside Operation Metal/Non-Metal

Riverside, Riverside County, CA  ·  Active
MSHA Mine ID: 0404263

Riverside Operation has $4K in proposed MSHA penalties and $0 outstanding across 2 contested dockets, plus health sampling and the full incident record.

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Fatalities
0
Total incidents
11
Years on record
1983–2026
Latest incident
Mar 2026
Compliance record
MSHA citations since 2000
31
citations
9
significant & substantial
$4,351
proposed penalties
$4,351
paid to date
100% of proposed penalties paid to date, a $0 gap.
Source: MSHA violations data, updated weekly.
Inspection activity
MSHA inspections since 2000
59
inspections on record
787
inspection hours
n/a
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: 787 inspection hours is too few for a stable rate. A minimum of 1,000 inspection hours is required.
Source: MSHA inspections data, updated weekly.

Riverside Operation has $4K 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.
$4K
proposed penalties
$4K
current assessed
$4K
paid to date
$0
outstanding
30 assessments are final orders; 2 contested dockets.
As of the most recent assessment on 2023-08-30.
Source: MSHA assessed-violations and conference/litigation data, updated weekly.
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
2025 Q4 1,607 0 0 0.0
2025 Q3 1,725 0 0 0.0
2025 Q2 1,963 0 0 0.0
2025 Q1 1,692 0 0 0.0
2024 Q4 1,598 0 0 0.0
2024 Q3 1,668 0 0 0.0
2024 Q2 1,661 0 0 0.0
2024 Q1 1,892 0 0 0.0
Show 96 earlier quarters
Quarter Hours worked Citations S&S Per 1M hrs
2023 Q4 1,511 0 0 0.0
2023 Q3 1,482 1 0 674.8
2023 Q2 1,834 0 0 0.0
2023 Q1 1,672 0 0 0.0
2022 Q4 1,602 0 0 0.0
2022 Q3 1,336 0 0 0.0
2022 Q2 1,396 0 0 0.0
2022 Q1 1,158 0 0 0.0
2021 Q4 1,265 0 0 0.0
2021 Q3 1,299 0 0 0.0
2021 Q2 1,214 0 0 0.0
2021 Q1 1,286 0 0 0.0
2020 Q4 1,249 0 0 0.0
2020 Q3 1,112 0 0 0.0
2020 Q2 1,429 0 0 0.0
2020 Q1 1,431 0 0 0.0
2019 Q4 1,485 0 0 0.0
2019 Q3 1,678 0 0 0.0
2019 Q2 1,705 0 0 0.0
2019 Q1 2,147 0 0 0.0
2018 Q4 2,008 0 0 0.0
2018 Q3 2,095 0 0 0.0
2018 Q2 1,648 0 0 0.0
2018 Q1 1,523 0 0 0.0
2017 Q4 1,404 0 0 0.0
2017 Q3 1,122 0 0 0.0
2017 Q2 1,378 0 0 0.0
2017 Q1 1,559 0 0 0.0
2016 Q4 1,488 0 0 0.0
2016 Q3 1,893 0 0 0.0
2016 Q2 1,947 0 0 0.0
2016 Q1 2,211 0 0 0.0
2015 Q4 2,493 1 0 401.1
2015 Q3 2,647 1 0 377.8
2015 Q2 2,391 0 0 0.0
2015 Q1 2,346 0 0 0.0
2014 Q4 2,479 0 0 0.0
2014 Q3 2,848 0 0 0.0
2014 Q2 2,801 0 0 0.0
2014 Q1 2,479 0 0 0.0
2013 Q4 2,360 0 0 0.0
2013 Q3 2,533 0 0 0.0
2013 Q2 2,735 0 0 0.0
2013 Q1 2,320 1 0 431.0
2012 Q4 2,422 0 0 0.0
2012 Q3 2,709 0 0 0.0
2012 Q2 3,221 0 0 0.0
2012 Q1 2,730 2 1 732.6
2011 Q4 2,211 0 0 0.0
2011 Q3 2,595 0 0 0.0
2011 Q2 2,737 0 0 0.0
2011 Q1 2,486 0 0 0.0
2010 Q4 2,355 0 0 0.0
2010 Q3 2,341 0 0 0.0
2010 Q2 2,341 0 0 0.0
2010 Q1 2,516 0 0 0.0
2009 Q4 1,993 1 1 501.8
2009 Q3 2,092 0 0 0.0
2009 Q2 1,877 1 0 532.8
2009 Q1 2,282 4 1 1752.8
2008 Q4 2,338 0 0 0.0
2008 Q3 2,300 0 0 0.0
2008 Q2 2,567 1 1 389.6
2008 Q1 2,084 0 0 0.0
2007 Q4 1,968 4 1 2032.5
2007 Q3 2,066 0 0 0.0
2007 Q2 2,070 0 0 0.0
2007 Q1 1,979 0 0 0.0
2006 Q4 2,004 0 0 0.0
2006 Q3 2,085 0 0 0.0
2006 Q2 2,384 1 0 419.5
2006 Q1 2,498 0 0 0.0
2005 Q4 1,803 0 0 0.0
2005 Q3 1,814 0 0 0.0
2005 Q2 2,492 0 0 0.0
2005 Q1 2,185 0 0 0.0
2004 Q4 2,295 3 2 1307.2
2004 Q3 2,613 0 0 0.0
2004 Q2 2,526 0 0 0.0
2004 Q1 1,863 0 0 0.0
2003 Q4 1,701 1 0 587.9
2003 Q3 2,119 0 0 0.0
2003 Q2 2,320 2 0 862.1
2003 Q1 1,876 0 0 0.0
2002 Q4 1,814 2 1 1102.5
2002 Q3 1,766 0 0 0.0
2002 Q2 1,618 0 0 0.0
2002 Q1 1,665 2 0 1201.2
2001 Q4 1,636 0 0 0.0
2001 Q3 1,834 0 0 0.0
2001 Q2 2,338 2 1 855.4
2001 Q1 2,382 0 0 0.0
2000 Q4 2,197 0 0 0.0
2000 Q3 2,693 0 0 0.0
2000 Q2 3,304 0 0 0.0
2000 Q1 2,663 1 0 375.5
No fatalities recorded at this mine.

Reportable incidents

11 on file

2026 · 1 incident

March 19, 2026 CA · Metal/Non-Metal maintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service tech HANDLING OF MATERIALS
Riverside Milling Company, LLC · Struck against stationary object

The employee was welding a portable hopper in the warehouse and took off their welding helmet to grind. They put on their face shield but not their hard hat and after grinding, stood up, striking their head on the leg stand of the hopper cutting their forehead.

2011 · 2 incidents

September 14, 2011 CA · Metal/Non-Metal ledgeman/hand, quarry man DUST DISEASE OF LUNGS
Premier Silica LLC · Inhalation of radiations, caustics, toxic and noxious substances

On the above date the miner was confirmed to have silicosis by medical professional.

February 7, 2011 CA · Metal/Non-Metal maintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service tech HANDTOOLS (NONPOWERED)
Premier Silica LLC · Fall onto or against objects

On 3/28/2011, employee reported to his supervisor that he had an accident on 2/7/2011. Employee stated that he fell against hand rail while trying to loosen bin indicator with tool/cheater bar. Employee stated that he injured right shoulder when he fell against handrail. Accident under investigation at this time with insurance carrier.

1996 · 2 incidents

October 22, 1996 CA · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator MACHINERY
Premier Silica LLC · Caught in, under or between a moving and a stationary object

WHILE POSITIONING THE HOIST HE WAS HOLDING THE CHAIN AND ACCIDENTLY PUSHED THE UP BUTTON. THIS CAUSED HIS FINGER TO BE PULLED INTO THE CHAIN GUIDE.

August 24, 1996 CA · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator HANDTOOLS (NONPOWERED)
Premier Silica LLC · Fall to the walkway or working surface

USING PRY BAR TO HELP MOVE GEAR ON SHAFT, UNDER NORMAL CONDITIONS, WHEN BAR LOST ITS BITE. FELL BACKWARD REACHING BEHIND TO BREAK FALL WITH LEFT ARM.

1991 · 1 incident

July 22, 1991 CA · Metal/Non-Metal haul/off road/coal/ore/pit/quarry/rock/rubber tire truck driver, transportation truck driver MACHINERY
Premier Silica LLC · Struck by... (Not Elsewhere Classified)

HOSE PRESSURE LOST GRIP. SKIN ABRAISION ON L FOREARM.

1989 · 1 incident

September 15, 1989 CA · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator HANDLING OF MATERIALS
Premier Silica LLC · Struck by falling object

HE WAS HOLDING A PANEL OF MATERIAL STEADY WHILE HELP GOT INTO POSTION TO HOIST THE PANEL. THE PANEL SLIPPED AND FELL AND LANDED ON HIS LEFT FOOT BEHIND THE SAFTEY TOE OF HIS BOOT.

1985 · 1 incident

May 22, 1985 CA · Metal/Non-Metal maintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service tech SLIP OR FALL OF PERSON
Premier Silica LLC · Fall to the walkway or working surface

EE WAS TIGHTENI3G A BOLT & LOST HIS FOOTING. RESULTING IN TWISTING HIS LEFT KNEE.

1984 · 2 incidents

September 24, 1984 CA · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator MACHINERY
Premier Silica LLC · Flash burns (welding)

WELDING NEW PLATES IN AIR SEPARATOR INNER CONE AND RECXEIVED FLASHBURNS TO BOTH EYES FROM TGHE ARC WELDER

June 20, 1984 CA · Metal/Non-Metal warehouseman, bagger, palletizer/stacker, store keeper, packager, fabricator, cleaning plant operator STEPPING OR KNEELING ON OBJECT
Premier Silica LLC · Fall to lower level, (Not Elsewhere Classified)

HE WAS PUSHING A STEEL LINER PLATE INTO PLACE WHEN HIS FOOT SLIPPED ON A BOLT, CAUSING HIM TO FALL THRU THE MILL DOOR OPENING. THIS RESULTED IN FRACTURING HIS LEFT 9TH RIB.

1983 · 1 incident

May 11, 1983 CA · Metal/Non-Metal maintenance man, mechanic, repair/serviceman, boilermaker, fueler, tire tech, field service tech POWERED HAULAGE
Premier Silica LLC · Caught in, under or between (Not Elsewhere Classified)

VACUUM HOSE CAUGHT BETWEEN PULLEY AND BELT WHICH HE PULLED OUT HE THEN PROCEDED TO DO IT AGAIN BUT THIS TIME PULLEY CAUGHT LEFT HAND BETWEEN BELT AND PULLEY THIS STOPPED THE MOTION OF THE BE BELT IT TRAPPED HIS HAND CHIPPED A BONE IN LEFT WRIST AND CONTUSIONS TO LEFT ELBOW

For insurers, brokers, and safety consultants

The full compliance file on Riverside Operation

A dated report covering the 26-year penalty trail, line-item violation pattern, contest and docket posture, rate-normalized peer benchmark, and full fatality history. Delivered as a PDF with the underlying data as CSV.