Mining Project: Development of Guidelines for the Design of Support Systems to Manage Coal Mine Rib Hazards

Research Summary

This project had four research aims, as follows:

1. Analyze the current rib support practices and techniques in U.S. coal mines.
2. Evaluate the interaction of coal rib and rib-bolt-based support systems at specific sites to assist in the development of a rib-bolt interaction model.
3. Investigate the contributing factors to rib fatalities through historical analysis.
4. Develop a logical framework to be used to implement the rib brow support guidelines.

During the ten-year period of 2006 through 2015, there were 52 ground fall fatalities and 2,721 non-fatal days lost (NFDL) injuries at U.S. underground coal mining operations. For this period, pillar rib fall fatalities accounted for on average 21% of the fatal ground falls, and over the last five years, the number of pillar rib fall fatalities has risen to 29%. There were 668 NFDL injuries caused by rib falls for the period of 2006 through 2015. The NFDL injuries caused by rib falls for the last five years averaged 0.109 injuries per 200,000 hours.

This project attempted to reduce these hazards by developing guidelines and support methodologies for coal ribs. Rib brow support guidelines and methodologies were developed to minimize the risk and severity of injuries to coal miners. The effectiveness of these guidelines will be evaluated in the field. The goal is to reduce the level of exposure to rib instabilities by at least 25%.

Coal rib brow guidelines and design methodologies were developed based on calibrated numerical models of underground coal ribs. Finally, rib stability will be evaluated at several operating mines using the design guidelines and methodologies developed.

The impact of this research will be a reduction in the frequency and severity of injuries due to rib brow instabilities. The experienced reduction will depend on the mining conditions, but in many instances the hazard to the miner will be removed.