Worker killed at Lake Mead

Thomas Albert Turner, 44, of Henderson, Nevada, was one of three crew members setting the 6ft-long (1.8m) ring of steel-reinforced concrete segments in the 20ft diameter tunnel.

One of the segments slipped forward allowing pressurized grout to force through and strike Turner. The segment did not fall into the tunnel.
"There was a gap, and through that gap came the material, some grout and some rocks in sizes of 2in to 4in," said Robin Rockey spokesperson for the Southern Nevada Water Authority (SNWA). "It was about 200psi."

Initial reports from local media falsely announced workers had been trapped. "At no time were any workers trapped in the tunnel or exposed to toxic gasses. All other workers have been accounted for and are safe above ground. Furthermore, there was no flooding of the tunnel," said the SNWA in a release that day.

The accident happened 600ft underground at the worksite of Vegas Tunnel Constructors' (VTC a joint venture of Impregilo and its subsidiary S.A. Healy). VTC is building the 4.5km tunnel, which has seen several stops and starts due to flooding in the starter tunnel that eventually required realignment.

On Monday evening VTC's Tunnel Rescue Team examined the site of the accident, and later determined the tunnel to be safe for entry. VTC is currently cleaning the space and preparing to seal the approximate 4in by 2ft gap where the tunnel ring segment slipped forward.

OSHA and VTC are conducting a joint investigation of the accident. Tunnelling activity will not resume until it is determined how the segment slipped and how to prevent future slippage. It's too early to determine how this could affect the project's schedule, Rockey said

So far 133 concrete segment rings have been successfully placed, with a total of nearly 2,500 expected to complete the tunnel. All of the installed segments are stable.