Mission Support and Test Services is under investigation for two incidents in the summer of 2023 in which falling rock injured employees at the deep-underground explosive testing facility it is building in Nevada for the National Nuclear Security Administration.
The enforcement arm of NNSA’s Office of Enterprise Assessments notified Mission Support and Test Services (MSTS) of its intention to investigate the incidents in a Feb. 2 letter – published online four days later – to company President Garrett Harencak.
At issue are two groundfall events on June 29 and Aug. 22 “when loose and unsecured soil and rocks fell onto and significantly injured multiple miners” at NNSA’s Nevada National Security Sites’ Principal Underground Laboratory for Subcritical Experimentation (PULSE) facility, formerly called the U1a Complex. MSTS manages the Nevada Test Site on behalf of the NNSA.
Nearly 1,000 feet underground, the facility is designed for experiments that apply conventional high explosives to nuclear materials to determine their explosive properties without a full-yield nuclear explosion. Following the Comprehensive Nuclear Test Ban Treaty, the U.S. has not conducted a yield test since 1992.
In the June incident inside the mine, two employees were on a scissor lift removing and replacing overhead shotcrete when the sprayed concrete collapsed on them, according to MSTS and the Nevada Field Office. Both employees were injured and transported to a local hospital for treatment and later released.
“The injuries from this event could have been more significant,” the MSTS and the Nevada Field Office said in a report on the incident. There was no immediate impact to the facility, but work was temporarily stopped and the accident area was cordoned off.
The following day, the area was assessed by Engineering, Safety, Construction, and facility personnel and it was decided that, using steel “Volcano-plate” washers bolted into the rock and mesh, the area could be made safe. Work was again stopped once the ceiling was shored up. The incident ultimately was classified a “near miss,” according to MSTS and the Nevada Field Office.
On Aug. 22, two miners were performing “rock bolting” when “ground movement” caused dirt and rocks to fall on them, according to the report. Both employees were injured with one requiring surgery to his left hand and forearm that was scheduled for Aug. 23.
A spokesperson for MSTS told Exchange Monitor that the incidents did pause work in the mine for a few days but should not ultimately delay completion of the project.
“The pacing item(s) for new PULSE capability completion is a combination of the infrastructure installation and equipment commissioning,” the MSTS spokesperson said. “While work was paused to address the incidents and to ensure safety of the work and workers going forward, the areas were remediated within days of both incidents and will not affect the completion of work.”