Outside Foreman

On March 22, 2016 at approximately 6:35pm an employee was struck by flyrock after a shot was detonated. The employee was sitting inside of a pickup approximately 1,200 feet away from the shot when detonated. This incident resulted in a fatality.

Tracy L. Hockemeier, Leadman, age 42, was fatally injured on March 22, 2016, when he was struck by fly rock during blasting operations in the Winterset section of Plant 862. Hockemeier was sitting in a pickup truck, approximately 1,200 feet from the blast site, preventing others from entering the blast area. When the blast was initiated, fly rock was propelled upward, landing on and penetrating the roof of the truck and striking the victim. The accident occurred as a result of multiple factors, including geology of the blast area, the condition of and loading of blast holes, and failure to communicate between the mine operator and contractor blasters. The mine operator and contractors failed to ensure that the blast area was cleared, or adequate shelter taken, prior to initiating the shot. The victim was not task trained for evaluating blast area clearance or blasting procedures.

1. Management’s policies, procedures and controls failed to adequately assess the geology or material to be blasted; blast pattern, burden, depth, diameter, and angle of the holes; historical blasting experience at this mine; delay system, powder factor, and pounds per delay; type and amount of explosive material; type and amount of stemming and their inter-relationship with each other in properly determining the blast area.

   Corrective action: Management established updated blasting policies, procedures and controls to ensure persons are not exposed to fly rock. Management trained all affected mine employees so that that mine supervision and blasting personnel have better communication regarding variable blasting pattern conditions and avoid fly rock potential.

2. Management’s policies, procedures and controls failed to ensure the blasting contractor complied with applicable mandatory standards of adequately assessing the potential for fly rock, by failing to communicate geological conditions effectively. Information regarding which drill holes were unloadable as a result of mud seams or voids encountered in the drilling and loading process, the geological conditions, and water infiltration of holes would have provided critical knowledge to warrant an expanded security area for the blast.

   Corrective action: Management established updated blasting policies, procedures and controls to ensure persons are not exposed to flyrock. Management trained all affected mine employees so that that mine supervision and blasting personnel, including contractors, have better communication of variable blasting pattern conditions and reduce fly rock potential.

3. Hockemeier was not task trained to assess the geology or material to be blasted; blast pattern, burden, depth, diameter, and angle of the holes; historical blasting experience at this mine; delay system, powder factor, and pounds per delay; type and amount of explosive material, type and amount of stemming and their inter-relationship with each other in properly determining the blast area so persons were not exposed to flyrock.

   Corrective action: Management established updated blasting policies, procedures and controls to ensure persons are not exposed to fly rock. Management established policies to train persons to properly assess blast sites and trained all affected mine employees so that that mine supervision and blasting personnel have better communication of variable blasting pattern conditions and reduce fly rock potential.

Findings from MSHA's final investigation report, which supersedes the preliminary narrative above.

Activity at time of incident

Observe Operations

Subunit / location

STRIP, QUARY, OPEN PIT

Accident type

Struck by flying object

Source of injury

BROKEN ROCK,COAL,ORE,WSTE

Nature of injury

CRUSHING

Body part affected

HEAD, MULTIPLE PARTS

Total mining experience

6 years

Experience at this mine

0 years

Experience in this job

0 years

Degree of injury

FATALITY