Cornerstone Materials Inc · Over-exertion (Not Elsewhere Classified)
EMPLOYEE WAS IN TOO MUCH OF A HURRY WHILE CARRYING TOO LARGE OF A LOAD. HE STUMBLED TWISTED HIS LOWER BACK AND PULLED MUSCLES IN LOWER BACK.
Portable Unit No 1: 2 reportable incidents Metal/Non-Metal
Cornerstone Materials Inc
· Surface
Controlled by
Stewart John W
Maricopa County,
AZ
·
Abandoned
MSHA Mine ID: 0201135
Portable Unit No 1 has had no fatalities among 2 reportable incidents since 1983.
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- Fatalities
- 0
- Total incidents
- 2
- Years on record
- 1983–1987
- Latest incident
- Apr 1987
Ownership history
- Hunter Contracting Company 1950 to 1979
- Cornerstone Materials Inc 1979 to present
Source: MSHA controller and operator history, updated weekly.
Workforce and production
| Year | Employees |
|---|---|
| 1989 | 3 |
| 1988 | 7 |
| 1987 | 9 |
| 1986 | 8 |
| 1985 | 6 |
| 1984 | 7 |
| 1983 | 5 |
Source: MSHA quarterly employment and production, updated weekly; years before 2000 come from MSHA's archived Part 50 employment files.
Portable Unit No 1 sits in Maricopa County, Arizona, where the Census mining category is 0.2% 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.Maricopa County, Arizona · Population 4,491,987
0.2%
Mining share of county employment
$85,518
Median household income
Source: US Census Bureau, American Community Survey 2023 5-year estimates.
No fatalities recorded at this mine.
Reportable incidents
2 on file1987 · 1 incident
Show 1 earlier incidents Hide earlier incidents
1983 · 1 incident
December 12, 1983
AZ · Metal/Non-Metal
bulldozer operator, universal operator, heavy equipment operator, operating engineer
HANDLING OF MATERIALS
Cornerstone Materials Inc · Struck by... (Not Elsewhere Classified)
REMOVING ROCK FROM CRUSHER SHOOT BOUNCES AND HIT HAND CAUSED BY METAL PROTRNDING FRON SHOOT WHICH DEFECTED TITLE PATH OF THE MATERIAL.