Improving ventilation in underground mines with large openings is the focus of a new project funded by the Center for Disease Control's Office of Mine Safety and Health Research.
Penn State researchers received a five-year, $1.25 million grant to study ventilation systems used in these mines, which account for about 60% of metal and nonmetal mines in the United States.
"This research is important because it can improve safety and offer better design guidelines for mine ventilation systems, which are not understood in detail in the United States," said Sekhar Bhattacharyya, associate professor of mining engineering in the John and Willie Leone Family Department of Energy and Mineral Engineering, and principal investigator on the study. "There is popular misconception that mining research at Penn State focuses solely on the coal industry. This project makes a bold statement about the depth and breadth of mining research at our University."
The Department of Interior's Mining Safety and Health Administration regulates miners' exposure to concentrations of diesel particulate matter (DPM). Reductions to safe limits have created a pressing need to improve ventilation design and optimize systems to move fresh air to different parts of mines as needed, according to the researchers.
Operators often use booster fans to improve airflow to various parts of a mine. But compared to coal mining in constricted openings in compact seams, this process can be especially challenging to control in large-opening mines. Their high volume makes it difficult to move and to direct adequate quantities of fresh air to dilute DPM concentrations and to maintain a healthy workplace environment, the scientists said.
Seasonal changes in weather also impact natural ventilation in shallow, large-opening mines due to heat transfer between circulating airflow and rock strata.
"It is well-known that seasonal changes in natural ventilation significantly influence the ventilation of these mines," said Shimin Liu, associate professor of mining engineering and co-PI on the project. "However, the manner and intensity of these changes has not been systemically and dynamically analyzed and subsequently codified and incorporated into ventilation planning and optimization."
With this funding, the researchers will work to develop new tools to better understand booster fan placement, design and optimization, DPM emission and transport behavior in mines, and how seasonal ventilation pressure contributes to rock-to-air energy exchange.
By improving modeling capacity and creating dedicated tools for booster fan optimization, the researchers said they hope to advance our knowledge of air recirculation in large-opening mines.
Also included on the project from Penn State is Derek Elsworth, professor of energy and geo-environmental engineering.