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| NIOSH researchers collecting rock stability data in a limestone mine |
Description of Problem
During 1986-1995, more than 20% of the fatalities in the U.S. stone mining industry occurred at underground operations. Large number deaths occurred during 1992-1993 when 14 stone industry fatalities occurred, of which 10 were in underground mines. Ground control problems were targeted for research because 8 of those 10 deaths were attributed to roof and rib falls. In the early 1990s, most stone mines were much smaller and lacked even the most basic levels of ground control.
Research and Development Activities
Before 1994, only the Mine Safety and Health Administration and the National Stone, Sand & Gravel Association focused on safety issues in stone mines. Most of their activities were geared toward surface quarries. However, over the last 10 years, NIOSH initiated a program to raise the awareness and application of sound ground control practices for underground stone mines. Three methods were used to achieve this goal: (1) increase the use of roof monitoring technology to warn of roof falls, (2) promote safe mine design layouts, and (3) transfer this knowledge, along with other common techniques, to control the ground through annual seminars and one-on-one interactions at the mine sites. The broadest measure of NIOSH's impact in lowering ground fall fatalities and injuries is the documented exposure (estimated 70%) to operators and miners working in the underground stone sector since 1999.
Description of Intermediate Outcome
Following a rash of ground fall injuries in the early 1990s, NIOSH became active in promoting sound engineering safety practices in the underground stone industry. NIOSH researchers observed that this industry was not using the most advanced monitoring and design technology to control its fall-of-ground problems as practiced in other underground mining sectors. To this end, roof fall forecasting techniques were promoted and improved upon, producing more monitoring activities at mine sites than in past years. In addition, innovative mine layout designs were researched and implemented at several underground mine sites. These new designs have resulted in safer engineered mine layouts with less hazardous ground conditions. Finally, an extensive technology transfer program was initiated that included the annual Safety Seminar for Underground Stone Mines, mine site visits, and technical publications. All of these promote the safest practices and procedures for controlling hazardous ground conditions.