In the mining industry, most of the underground injuries and fatalities are due to rock falls (i.e., fall of hanging wall/roof). The method that has been used for many years in the mines when determining the integrity of the hanging wall is to tap the hanging wall with a sounding bar and listen to the sound emitted. An experienced miner can differentiate an intact/solid hanging wall from a detached/ loose hanging wall by the sound that is emitted. This method is subjective. The Council for Scientific and Industrial Research (CSIR) in South Africa has developed a device that assists any miner in making an objective decision when determining the integrity of the hanging wall. A trained neural network model is embedded into the device. The device then records the sound emitted when a hanging wall is tapped.

Questions for Discussion
1. How did neural networks help save lives in the mining industry?
2. What were the challenges, the proposed solution, and the obtained results?