Christopher Mark  

As a teen working in West Virginia coal mines, Christopher Mark first learned about “roof falls,” the chief cause of underground fatalities in a job rife with dangers. Rather than being daunted, he decided to make mines safer. 

Over a decades-long career, Mark developed computer software packages that contain guidelines routinely used by mine operators to develop and evaluate mining plans for most underground coal mines in the U.S. A world-renowned expert, he’s credited with saving an untold number of miners’ lives.  

“Fifty years ago, underground coal mining was the most hazardous job in the United States, and roof falls killed more miners than all other causes put together—nearly 100 miners per year,” said Gregory Rumbaugh, roof control division chief at the Labor Department’s Mine Safety and Health Administration.  

In 2016, there were zero fatalities attributed to roof fall, the first such year, Rumbaugh said. “Christopher Mark has saved the lives of many coal miners. He was the glue, the center, when it comes to the road map to zero fatalities.” 

A roof fall is just that—the support holding up a mine’s roof fails, and a mass of rock or coal collapses into the mine. Even larger collapses involve the “pillars” of unmined coal that miners leave in place as they work in the mine’s various “rooms.”  

After working in mines, Mark went on to earn a doctorate in mining engineering. He spent 25 years as a researcher at the Bureau of Mines before moving to MSHA, which regulates mine safety. He pioneered a case-history approach to mine research, novel at the time. 

“He personally went out to many mines, collected their case histories, looked through mine maps and put all that information into a big database,” Rumbaugh said. That included hundreds of pillar designs and layouts.  

Key discovery 

Before, Rumbaugh said, “regions of the U.S. just used local rules of thumb and local experience to guide how they’re going to lay out their mines.” 

Mark discovered that an issue in roof falls wasn’t so much the vertical stress of weight on the rock, but horizontal stress from plate tectonics—the subterranean shifts of the Earth that give rise to mountains and cause earthquakes.  

“It’s a unique type of engineering because rock is a natural material with geologic history,” Mark said. “It’s different in every mine so this makes it difficult to design.”  

A turning point in his career—and in mine safety—was the August 2007 collapse at the Crandall Canyon Mine in Utah that killed nine. Inadequate mine design and engineering that led to failure of roof-supporting pillars were blamed. Mark was asked by Congress to make recommendations on pillar design and roof control, now incorporated in an MSHA handbook. 

Building on his early research, Mark developed software tools to help determine what size pillars to use, how much roof support to put in and how to evaluate horizontal stress. He created a mine roof rating scale now used globally, and he published more than 160 technical papers. His work is used in underground mining of other commodities such as salt and limestone, and he has consulted for Canada, Australia, China and others. 

Changing the culture 

Mark’s work has meant a change in coal mining culture, said George Gardner, Pittsburgh Safety and Health Technology Center chief at MSHA. 

“The attitude used to be that mining was just hazardous and not much to do about it,” he said. “Chris had to convince people that no—this is an engineering problem, and we can solve it.” 

Mark “was successful in changing the mentality and the safety culture of operators and workers,” said Zach Agioutantis, professor and chair at the Mining Engineering Foundation of the University of Kentucky. “With Chris’s interventions, safety has improved immensely. That’s his motivation—to keep people safe at all costs.” 

“No one can fully predict when mine failures are happening,” Mark says. “What can be done is to identify signs of higher risks.” 

With his background and experience, Mark is listened to by all sides, said Melanie Calhoun, technical support director at MSHA. “He knows what it means to work in a mine. It makes him special. He is a unicorn when it comes to mining.”