Inspection Detail

Inspection: 100729755 - Siemens Energy & Automation, Inc.

Inspection Information - Office: Syracuse Area Office

Investigation Summary

EMPLOYEE #1 AND 3 OTHER EMPLOYEES WERE WORKING ON A TUNNEL DRILLING PROJECT FOR A HYDRO PLANT UNDER CONSTRUCTION. EMPLOYEE #1 AND THE OTHER EMPLOYEES WERE WORKING IN THE PIT AREA JUST OUTSIDE THE PORTAL AREA FOR THE TWO TUNNELS. THEY WERE MOVING MACHINERY IN PREPARATION FOR RE-ENTRY INTO TUNNEL #2 TO BEGIN DRILLING OPERATIONS. 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 WITH AN AIR TRACK DRILL. ANOTHER EMPLOYEE WAS USING A TRAXCAVTOR TO REMOVE ROCK WHICH 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. THE ROCKS FELL FROM THE TOP OF THE FACE, ABOUT 100 FEET UP. EMPLOYEE #1 WAS KILLED. NONE OF THE OTHER EMPLOYEES WERE INJURED. THE COMPANY BEGAN EXCAVATING THIS AREA, AT GROUND LEVEL, IN JANUARY 1986. THEY HAD DUG DOWN ABOUT 100 FEET DURING THE INTERVAL. THE ROCK FACE WAS VERTICAL. THE TOP 15 TO 20 FEET WAS BADLY FRACTURED, WITH NUMEROUS MUD SEAMS. THERE WAS A VERY DISTINCT MUD SEAM AT THE 20 FOOT 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, BUT 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 BEEN EXPOSED TO THE WEATHER SINCE JANUARY 1986. NO ONE WAS ASSIGNED TO CHECK THE CONDITION OF THE ROCK FACE ON A REGULAR INTERVAL. THE NIGHT BEFORE THE ACCIDENT, HEAVY RAIN FELL IN THE AREA. ALSO, THERE WAS A BLAST IN TUNNEL #1 15 TO 20 MINUTES BEFORE THE ROCKS FELL.

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