Forensic Investigation

Single Abstract

340925 - Simultaneous Collapse of Three Raw Coal Conveyors at the Largest Underground Coal Mining Complex in North America

Saturday, April 21
10:00 AM - 11:30 AM
Location: 202B

On the evening of July 27, 2012, three raw coal conveyor belt structures simultaneously collapsed, shutting down the processing facilities at the largest underground coal mining complex in North America. Two miners working next to the conveyors heard the structures failing above and fled the area. Two of the conveyors were new and had only been in service for a little over two weeks. The third belt was old and had recently been taken out of service when the new ones became operational. One of the new belts had been operating at a reduced capacity since it was first put into service, but its capacity had been increased on the day of the failure. Telltale signs that the structure had deficiencies had been discovered weeks prior when the belts were commissioned, but had not been comprehensively investigated.

Following the failure, the Mine Safety and Health Administration (MSHA) investigated the collapse and found that a bolted connection failed at the end of a cantilever beam that supported a skewed beam. The skewed beam was supporting the trusses for one of the new belts at the top of a shared bent. The bolt failure then led to load redistribution, resulting in twisting of the cap beam and buckling of the outer bent column. Instability at the bent caused both new belts to partially collapse, with one of them falling onto the old one below.

This paper discusses the background of the collapse, a description of the conveyors and their supports, the nature of the loading, a summary of the events preceding the failure, post-collapse observations, structural analyses, failure modes considered, a design deficiency identified, and conclusions.

Terence M. Taylor

Senior Civil Engineer
Mine Safety and Health Administration

I have 30 years of experience with the Mine Safety and Health Administration's (MSHA) Technical Support center in Pittsburgh. I have a Bachelor’s degree from Penn State University and a Master’s degree from the University of Colorado. Both degrees are in Civil Engineering with a specialization in Structural Engineering.

I have been involved with numerous structural inspections, failure investigations, and technical assistance requests relating to: processing plants, conveyor support systems, storage bins, silos, stacking tubes, tanks, radial stackers, draglines, cranes, crushers, mine shaft supports, mobile equipment, draw-off tunnels, retaining walls, temporary supports, scaffolding, and rigging.

I have served as an expert witness for MSHA on citations relating to structural engineering. In addition, I have presented structural safety training to numerous groups of MSHA employees, miners, industry professionals and mine management.

I am also a registered Professional Engineer in the state of Pennsylvania.

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340925 - Simultaneous Collapse of Three Raw Coal Conveyors at the Largest Underground Coal Mining Complex in North America



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