Mining Topic: Rock Falls

What is the health and safety problem?

Falls of rock from the roof are one of the leading causes of injuries and fatalities for mine workers.

What is the extent of the problem?

Underground mining still has one of the highest fatal injury rates of any U.S. industry—more than five times the national average compared to other industries. Between 1999 and 2008, nearly 40% of all underground fatalities were attributed to roof, rib, and face falls. Small pieces of rock falling between bolts injure 400–500 coal mine workers each year.

How is the NIOSH Mining Program addressing this problem?

 The NIOSH Mining Program is working to combine empirical, laboratory, and numerical studies to advance the state-of-the-art methods for protecting mine workers from all forms of rock fall. Major roof falls and rib falls are the focus of our current work, including studies to improve the support design methodologies and to provide "best practices" through training and health communications. NIOSH is also funding and collaborating on external research projects. This work focuses on early fall warning devices and improved bolting equipment, which primarily involves smart bolters that evaluate the roof composition and conditions in real time while bolting.

What are the significant findings?

NIOSH has made significant findings in the areas of "best practices" related training and improved fall warning devices. Improvements in technology, such as the use of personal bolter screens to prevent small falls and reduce injuries, have been found to provide significant protection to mine workers in many instances.

What are the next steps?

NIOSH is actively investigating how to protect mine workers from rock falls in ribs of coal mines and apply numerical modeling tools to design support that will reduce large falls of roof. NIOSH Mining’s comprehensive approach to ground control looks at global stability which can be maintained with good pillar design, local stability which can be maintained with good roof controls, and surface or skin control with screening.