A CSIR-developed electronic sounding device.
A device invented by the CSIR used in the detection of loose overhead rock in underground mines has been commercialised. An electronic sounding device is a sensor that mimics the performance of an experienced miner in determining whether loose rocks are present in the roof of the excavation during the entry inspection.
Rock-falls the biggest killer in SA mines
With rock falls responsible for more than 30% of the fatalities in South African gold and platinum mines, the entry inspection that occurs before workers enter a newly blasted workplace is one of the most important and dangerous tasks in underground mining operations.
The current process used in ensuring that there are no dangerously loose overhead rocks in a newly blasted underground work area includes tapping the roof of the excavation with a pry bar. If the area tapped sounds hollow, it means the rock is loose. The loose rock will then be pried from the roof using the same pry bar for sounding the hanging wall.
A tool to aid in detection of loose rock
A major factor in detecting loose rocks is the sounding process. The sounding process is an acquired and somewhat subjective skill. The quality of sounding is related to the physical state of the miner undertaking the sounding. Fatigue, noise-induced hearing loss and illness often affect the competence of individuals, even within a single shift.
The sounding device improves the sounding process in the detection of loose rocks. Tests conducted at Gold Fields’ Driefontein mine showed that the device had a high degree of correlation with skilled human operators. Thus, the device can be used where skilled operators are not available or when the skilled operators can no longer perform the function due to noise-induced hearing loss, which is common in the mining environment.
After the successful demonstration of working prototype, the device has been positively received by the industry. As a result, the CSIR finalised an agreement with Draxin Technology to manufacture and use the ESD technology under licence.