OSHA Accident Investigation · Summary #14490304

ROCK,STRUCK BY,EXCAVATION,UNSECURED,WORK RULES,CONSTRUCTION,CRUSHED,UNSTABLE SURFACE,FALLING OBJECT

1986-01-01T00:00:00

Event: ROCK,STRUCK BY,EXCAVATION,UNSECURED,WORK RULES,CONSTRUCTION,CRUSHED,UNSTABLE SURFACE,FALLING OBJECT
Linked inspection: No inspection record linked to this accident's victims.
Summary number: 14490304
Report ID: 215800

Event description

SECTION OF ROCK WALL COLLAPSED; EMPLOYEE STRUCK AND KILLED

Investigation abstract

EMPLOYEE #1 AND 3 OTHER EMPLOYEES WERE WORKING ON A TUNNEL DRILLING PROJECT FOR . THE ROCKS FELL FROM THE TOP OF THE FACE, ABOUT 100 FEET UP. EMPLOYEE #1 WAS KI LLED. NONE OF THE OTHER EMPLOYEES WERE INJURED. THE COMPANY BEGAN EXCAVATING THI S AREA, AT GROUND LEVEL, IN JANUARY 1986. THEY HAD DUG DOWN ABOUT 100 FEET DURIN G THE INTERVAL. THE ROCK FACE WAS VERTICAL. THE TOP 15 TO 20 FEET WAS BADLY FRAC TURED, WITH NUMEROUS MUD SEAMS. THERE WAS A VERY DISTINCT MUD SEAM AT THE 20 FOO T LEVEL. BELOW THAT THE ROCK WAS MORE SOLID AND STABLE. THE COMPANY PLACED WIRE MESH FROM THE TOP OF THE FACE DOWN TO ABOUT 10 FEET BELOW THE FRACTURED AREA, BU T THE WIRE MESH WAS NOT SECURED AT THE BOTTOM. THAT MEANT THAT ANYTHING FALLING FROM THE TOP WOULD FALL ALL THE WAY DOWN INTO THE PIT AREA. THE ROCK CUT HAD BEE N EXPOSED TO THE WEATHER SINCE JANUARY 1986. NO ONE WAS ASSIGNED TO CHECK THE CO A HYDRO PLANT UNDER CONSTRUCTION. EMPLOYEE #1 AND THE OTHER EMPLOYEES WERE WORKI NDITION OF THE ROCK FACE ON A REGULAR INTERVAL. THE NIGHT BEFORE THE ACCIDENT, H EAVY RAIN FELL IN THE AREA. ALSO, THERE WAS A BLAST IN TUNNEL #1 15 TO 20 MINUTE S BEFORE THE ROCKS FELL. NG IN THE PIT AREA JUST OUTSIDE THE PORTAL AREA FOR THE TWO TUNNELS. THEY WERE M OVING MACHINERY IN PREPARATION FOR RE-ENTRY INTO TUNNEL #2 TO BEGIN DRILLING OPE RATIONS. EMPLOYEE #1 WAS MOVING A JUMBO DRILL FROM IN FRONT OF TUNNEL #2 TOWARDS TUNNEL #1. TWO OTHER EMPLOYEES WERE PREPARING TO BEGIN DRILLING IN TUNNEL #2 WI TH AN AIR TRACK DRILL. ANOTHER EMPLOYEE WAS USING A TRAXCAVTOR TO REMOVE ROCK WH ICH HAD BEEN BLASTED LOOSE 15 TO 20 MINUTES EARLIER IN TUNNEL #1. WHILE EMPLOYEE #1 WAS MOVING THE JUMBO DRILL A 5 TON SECTION OF THE ROCK WALL FACE FELL ON HIM

Victims (8)

#1 Fatality Age 21 M

Nature of injury
6

Part of body
19

Event type
1

Source
12

Occupation code
999

Human factor
17

Environmental factor
6

Hazardous substance
8880

Task assigned
1
#981 Degree 0 Age 0

Nature of injury
0

Part of body
0

Event type
0

Source
0

Occupation code
0

Human factor
0

Environmental factor
0

Task assigned
0
#982 Degree 0 Age 0

Nature of injury
0

Part of body
0

Event type
0

Source
0

Occupation code
0

Human factor
0

Environmental factor
0

Task assigned
0
#983 Degree 0 Age 0

Nature of injury
0

Part of body
0

Event type
0

Source
0

Occupation code
0

Human factor
0

Environmental factor
0

Task assigned
0
#984 Degree 0 Age 0

Nature of injury
0

Part of body
0

Event type
0

Source
0

Occupation code
0

Human factor
0

Environmental factor
0

Task assigned
0
#985 Degree 0 Age 0

Nature of injury
0

Part of body
0

Event type
0

Source
0

Occupation code
0

Human factor
0

Environmental factor
0

Task assigned
0
#986 Degree 0 Age 0

Nature of injury
0

Part of body
0

Event type
0

Source
0

Occupation code
0

Human factor
0

Environmental factor
0

Task assigned
0
#987 Degree 0 Age 0

Nature of injury
0

Part of body
0

Event type
0

Source
0

Occupation code
0

Human factor
0

Environmental factor
0

Task assigned
0

Codes shown verbatim from OSHA's accident-investigation database. A human-readable decoder is coming in a future release once the accident_lookup2 dictionary is loaded.