Investigation on the precursors of bump-prone coal failure

The acoustic and thermal infrared (TIR) characteristics of bump prone coal during different loading tests are described. The experimental system is composed of the TIR observation system, the stress and strain measurement system and the acoustic emission monitoring system. The system can be used to achieve different kinds of precursors before the failure of rock or coal samples. The uniaxial compression loading test and the cyclic loading test are carried out to observe the features of TIR, acoustic emission, and strain variation. The response speed and the sensitivity of different monitoring units to the cracking events in the samples are also studied and the physical and mechanical characteristics of bump prone coal are obtained. The analytical results show that the stress of ninety percent of strength should be regarded as the stress-caution-zone for the failure of bump prone coal, which is much higher than the stress of seventy percent of strength as the stress-caution-zone for the general coal samples.