NR Hamm Quarry LLC · Struck by... (Not Elsewhere Classified)
The underground mine had a cave-in and employee is experiencing ringing of the left ear and headaches caused by the loud noise and air pressure.
Knoxville Mine Metal/Non-Metal
NR Hamm Quarry LLC
· Underground
Controlled by
Summit Materials LLC
Knoxville,
Marion County,
IA
·
Abandoned
MSHA Mine ID: 1302217
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- Fatalities
- 0
- Total incidents
- 10
- Years on record
- 2000–2025
- Latest incident
- Jun 2025
Compliance record
MSHA citations since 2000
798
citations
213
significant & substantial
$501,238
proposed penalties
$454,442
paid to date
Source: MSHA violations data, updated weekly.
Quarterly safety rates
Citations per million employee-hours, as reported to MSHA
| Quarter | Hours worked | Citations | S&S | Per 1M hrs |
|---|---|---|---|---|
| 2025 Q4 | 3,851 | 8 | 2 | 2077.4 |
| 2025 Q3 | 6,419 | 1 | 0 | 155.8 |
| 2025 Q2 | 7,870 | 5 | 0 | 635.3 |
| 2025 Q1 | 12,678 | 6 | 2 | 473.3 |
| 2024 Q4 | 6,958 | 0 | 0 | 0.0 |
| 2024 Q3 | 6,251 | 3 | 1 | 479.9 |
| 2024 Q2 | 6,458 | 0 | 0 | 0.0 |
| 2024 Q1 | 12 | 1 | 1 | 83333.3 |
Quarters under 100,000 reported hours are greyed: too few hours for a stable rate.
No fatalities recorded at this mine.
Reportable incidents
10 on file2025 · 3 incidents
NR Hamm Quarry LLC · Struck by... (Not Elsewhere Classified)
The underground mine had a cave-in and the employee is experiencing ringing in the left ear and headaches caused by the loud noise and air pressure.
NR Hamm Quarry LLC · Accident type, without injuries
An unplanned cave-in / release of material occurred underground during the second shift. During the second shift employees were loading shot rock and transporting to surface storage area when employees heard material falling and an accumulation of dust appeared in their area.
2020 · 3 incidents
November 12, 2020
IA · Metal/Non-Metal
blaster, shooter, shotfirer, explosive worker, powder gang/monkey
FALL OF ROOF OR BACK
Bruening Rock Products Inc · Struck by falling object
Employee was cleaning out a lifter hole by hand when some rock sluffed off the face and struck them in the back. Result was fractured ribs.
October 7, 2020
IA · Metal/Non-Metal
haul/off road/coal/ore/pit/quarry/rock/rubber tire truck driver, transportation truck driver
POWERED HAULAGE
Bruening Rock Products Inc · Struck against a moving object
Employee was backing up to dump, upon raising box, the rubber pads/bushing pulled apart from the suspension on the rear driver's side wheels causing the weight to shift on the box and tipping the truck over
September 15, 2020
IA · Metal/Non-Metal
haul/off road/coal/ore/pit/quarry/rock/rubber tire truck driver, transportation truck driver
SLIP OR FALL OF PERSON
Bruening Rock Products Inc · Over-exertion (Not Elsewhere Classified)
Employee was getting out of a haul truck with left hand on handrail behind door frame and right hand on door. Went to get down and turned body away from truck releasing right hand from the door and upon going to step down did not release left hand and dropped dislocating shoulder.
2018 · 1 incident
Bruening Rock Products Inc · Caught in, under or between running or meshing objects
The crushing plant had gotten plugged. After getting the plant unplugged EE was helping up a access door back on when EE's coat was snagged by the conveyor belt. EE's arm was pulled into the conveyor and tail pulley.
2007 · 1 incident
February 16, 2007
IA · Metal/Non-Metal
bull gang foreman, labor foreman, leadman, section foreman, shift boss
HANDLING OF MATERIALS
Bruening Rock Products Inc · Over-exertion in lifting objects
Employee was fixing/removing a guard on a tail section of plant. He stood up lifting guard and twisted right knee.
2000 · 2 incidents
Bruening Rock Products Inc · Accident type, without injuries
ROOF FALL IN ABANDON HEADING NO DAMAGE OR INJURYFILED 30FT OF HEADING BELEIVE THE AREA ABOVE HEADING IS OLD RIVER CHANEL DUE TO WATER EROSION LOST ROOF SUPPORT NO WAY OF KNOWING THIS AREA WAS AS LARGE OTHER AREA OF MINE ARE OK
January 7, 2000
IA · Metal/Non-Metal
continuous miner operator, coal mole operator
HANDLING OF MATERIALS
Bruening Rock Products Inc · Over-exertion in lifting objects
EMPLOYEE WAS MOVING A P4 WILDEN DIAPHRAM PUMP OUT OF FACE AREA. HE PICKED PUMP UP WITH ONE HAND (APPROX 20LB.) AND TWISTED TO THE SIDE TO SET THE PUMP DOWN AND FELT PAIN UNDER LEFT SHOULDER B LADE AND BACK.