Detectability of a self-illuminating lifeline for self-escape in smoke conditions of an underground mine

Lifelines are used to aid self-escape of underground miners, but they are difficult to find in low-visibility conditions of smoke, therefore a self-illuminating lifeline could facilitate miners in locating the lifeline. The detection distance, colour recognition, and miss rate for 10 subjects were determined for red-, green- and blue-lighted diffuse fibre-optic cables, used to create a lighted lifeline, and a traditional rope lifeline in a smoked-filled environment. The testing was conducted with and without a cap lamp. The use of a cap lamp resulted in all cases being undetected in 98.3% of trials. With the cap lamp off, there was no significant difference in the detection distance for blue- and green-lighted fibres; however, the miss rate for the green-lighted fibre was slightly higher. The red-lighted fibre was not detected in 93.3% of trials. The green- and blue-lighted fibres enabled the best visual performance, but subjects had difficulty correctly identifying the colour of the fibre. The lighted fibre-optic cable appears to have merit for improving self-escape from underground mines, and may have other mining and non-mining applications that include improving self-escape visibility.