Mining Topic: Geologic Characterization

What is the health and safety problem?

The U.S. underground mine worker faces a continuing hazard from roof falls and other ground control related hazards. Many injuries and fatalities are related to mine roof that is weakened as a result of geologic factors. The roof may consist of rock that is inherently low in strength such as drawrock, thinly bedded rock, or mudstone. Further, the roof may be weakened or damaged by discontinuities such as clay veins, slickensides, joints, faults, and paleochannels.

What is the extent of the problem?

Research relating to a wide range of geologic factors has contributed to the decline in the number of injuries and fatal accidents resulting from roof falls. However, according to Mine Safety and Health Administration (MSHA) statistics (1999-2008), falls of ground were responsible for the largest portion (26%) of fatal incidents in the coal mining industry and about 40% of fatal incidents in underground coal mining.

How is the NIOSH Mining Program addressing this problem?

The NIOSH Mining Program has developed, and is continuing to improve, methods for characterizing ground and its probable response to mining so that potential hazards can be identified and prevented.

What are the significant findings?

A number of tools – in particular classification and test methods – have been and continue to be developed. These include Coal Mine Roof Rating (CMRR) software, ground hazard mapping, ground condition mapping, diagnosis of moisture sensitivity, and gas content testing.

What are the next steps?

Further development of classification and test methods will continue in order to improve the ability of mine workers to anticipate hazards well before they are exposed.

---