Engineering faculty head underground mine studies focusing on safety and health

Virginia Tech College of Engineering faculty are leading two federally-funded projects to improve mine safety and health for underground workers, including bettering both firefighting techniques and the monitoring and abatement of diesel particulate matter.

Leading the investigations, funded by the National Institute for Occupational Safety and Health, part of the Center for Disease Control and Prevention, are Kray Luxbacher, an associate professor, and Emily Sarver, an assistant professor, both of the Department of Mining and Minerals Engineering.

Funded at $1.25 million each for five years, for a total of $2.5 million, the projects involve collaborators at other academic institutions and the private sector. In addition to worker safety, the efforts also seek to reverse a decline of expertise in both academia and industry by recruiting master’s and doctoral students who can enter the professional mining community upon graduation. 

“We have a vast shortage of people with technical expertise in mine health and safety,” said Sarver, calling coming industry needs dire.

Luxbacher will focus her efforts on computational modeling, taking data from an existing mine and using the virtual model to predict where potential fires could start, and how those fires could affect the mine ventilation system. Scenarios such as conveyor belt fires, fires along the mine’s exterior face caused by ignition of methane, and fires from collapsed or abandoned areas that spontaneously ignite will be studied.

“Modeling and characterization of mine fire behavior is critical for effective fire monitoring and early warning, evacuation of personnel, rapid response, and successful firefighting,” Luxbacher said in an abstract of the research proposal, adding that finding and eliminating high-risk fire areas is paramount.

Later work would move to physical modeling, with Luxbacher teaming with the Virginia Tech Extreme Environments Robotics and Materials Laboratory, headed by Brian Lattimer, an associate professor with the Department of Mechanical Engineering. 

Lattimer’s lab – ExtReMe or short – has a tests facility near campus that allows for fire simulations and study. Work would then move to a large scale fire tunnel in western Pennsylvania, where more physical tests will be carried out using staged fires.

Luxbacher also will team with Steven Schafrik, a research assistant professor with the university’s Virginia Center for Coal and Energy Research, and Jeffrey Borggaard and Serkan Gugercin, professors with the Department of Mathematics, part of the College of Science. The latter two will handle the computational figures in the study. They research also will involve a coal industry partner, and the Pennsylvania-based United Mine Workers of America Mine Training and Technology Center.

“This work allows for better emergency response and preparedness, but also accident prevention by assessing operational risks associated with fire hazards and the ability of an operation to respond to fire,” said Luxbacher.

Sarver’s work into monitoring and abating particulates from diesel exhaust in underground mines will include field work in an underground stone mine. The use of diesel-powered equipment in the mining industry is heavy, with trucks, loaders, and other equipment in constant use. In the enclosed environment, ensuring that diesel exhaust is removed is vital to protecting miner health. Therein lies Saver’s study.

Properly ventilating mines to remove harmful fumes and particles often is a challenge, and requirements are highly variable depending on mine geometry, production rate, and the equipment fleet, said Sarver. Diesel particulate matter has been described as a possible carcinogenic. Further troubling: The particles are less than one micrometer in size, and therefore exceedingly difficult to monitor and physically remove from the air. Mine health and safety advocates have “growing concerns” about air quality, she added.

In Sarver’s study, laser sensors will measure light reflected from air filters in different areas of the mine. Cleaner filters, which reflect more light, can indicate that diesel particulate is being adequately removed. 

While this sensor technology already is in wide use, it is only used in handheld devices which operate using a battery pack. Sarver’s team will test the technology for longevity in autonomous monitoring units that will remain stationary, testing their ability to track long-term trends in particulate concentrations. 

If successful, research will then turn to using the monitors to evaluate different ventilation practices.

Sarver also will create an in-lab diesel particulate matter abatement experiment at Randolph Hall on the Virginia Tech campus, using water sprays to remove particles from the air. Water sprays are heavily used in a variety of ways, including construction sites to prevent dust clouding. 

In most applications, sprays primarily work by wetting material so that particles cannot become airborne. The process will be duplicated here, targeting airborne particles.

“When diesel exhaust and water droplets combine, the particulate matter should fall out of the air,” said Sarver, “the trick will be getting the collision to happen.”

For this latter part of the study, Sarver will team with John R. Saylor, a mechanical engineering professor from Clemson University who specializes in interactions between water droplets and airborne particles.

Both research projects by Luxbacher and Sarver include funding for several research positions to be held by master’s or doctoral students, thereby answering a growing shortage of expertise within the mining industry. During the next decade, a large population – more than half – of current industry and academic experts in mining are expected to retire. 

Luxbacher and Sarver seek to fill the pending vacancies with fresh expertise who will enter the private sector and also enter the academic field on the university level.

The new federal projects follow several research endeavors underway in the mining department. Last year, Luxbacher, Sarver, and Schafrik received awards from the Alpha Foundation for the Improvement of Mine Safety and Health to focus on risk management, respirable dust characterization and underground communications systems. Awarded in fall 2013, the work totals $1.3 million.