A 69-year-old worker at an Indiana surface mine died when the haul truck he was operating traveled through a faulty berm that workplace exams didn’t identify and became submerged in a pond.
Mine Safety and Health Administration (MSHA) investigators determined that the incident occurred because inadequate workplace examinations failed to catch the berm, which wasn’t substantial enough to impede the haul truck from overtravel.
Common practice for drivers to contact berm before dumping
Bruce Vernon was a laborer for Mulzer Crushed Stone Inc. at the Cape Sandy #1 mine, a surface limestone mine in Crawford County, Indiana. The mine drills and blasts the limestone and uses haul trucks to transport the limestone to the plant for sizing.
On Sept. 12, 2023, Vernon and a co-worker were assigned to use haul trucks to haul material from a previously built ramp in a mining pit to the mine’s exit road spoil pile. Two other co-workers eventually joined in the task of moving material from the pit to the spoil pile.
The spoil pile was the site where the mine’s waste material was dumped. A large pond was located at the bottom of this dump site. The edge of the dumping area had berms which were meant to keep haul trucks from backing up too far and falling into the pond below. These berms were made of dirt and rock and came to a narrow, tapered point at the top.
It was common practice at the mine for haul truck drivers to back up until they contacted the berm before dumping their loads down the 250-foot drop into the pond.
Haul truck traveled through berm before falling
At 2 p.m., Vernon backed his haul truck up to dump at the top of the spoil pile, traveled through the berm and fell. One of Vernon’s co-workers saw his truck back over the berm and fall into the pond where it quickly became submerged.
The co-worker called for help via radio, leading to a 9-1-1 call. Emergency responders arrived onsite at 2:52 p.m. but they couldn’t find Vernon. As night fell, they had to call off rescue efforts until the following morning.
The next day, emergency responders recovered Vernon from the haul truck. They had to cut through his seat belt to get him out of the truck.
Workplace exams were conducted from truck cabs
MSHA investigators found that the berms around the spill pile dump site ranged in height from 21 inches to 38 inches. The haul truck had a mid-axle height of 52 inches. Between the low height and the use of loose dirt and rock, investigators determined that the berms were too insubstantial to keep haul trucks from traveling over the edge.
The state of the berms should have been something addressed by workplace examinations, according to MSHA. However, investigators learned that workplace examinations at the Cape Sandy #1 mine were less than adequate.
Multiple miners told investigators that the first person in the work area was responsible for conducting the workplace examination. They also said it was common practice to conduct workplace examinations from the cab of equipment, which was how the examination was conducted on the day of the incident.
The mine operator was unable to provide any records of workplace examinations conducted at the incident location. Further, training records revealed that the worker who performed the examination on the day of the incident wasn’t trained to perform workplace examinations.
While investigators were unable to examine Vernon’s haul truck, which the mine operator was unable to recover, there was no evidence that the truck had any defects that contributed to the incident.
Mine operator revised exam procedures
MSHA determined that the root causes of the incident were the mine operator’s failure to:
- ensure that berms at the dump site were capable of preventing overtravel, and
- conduct adequate workplace examinations.
To prevent similar incidents, the mine operator re-trained all of its employees on proper berm construction, reminding them that all berms must be constructed from substantial materials and must be tall enough to reach the mid-axle height of the largest vehicle traveling in the area.
Workplace examination procedures were also revised and the employees were trained on those, as well.
The new procedures require a competent person or a supervisor to conduct and document the examination. Exams must be conducted with sufficient lighting and any deficiencies or unsafe conditions must be noted and corrected.
