Use of spacer aided initiation technique in solid blasting in Indian underground coal mines

Solid blasting mining methods contribute about 60% of total underground coal production in India. Spacer aided initiation technique utilises the inherent air gap sensitivity of the explosive to distribute the blast energy over a longer length by the use of air decking using plastic spacers with single priming to achieve higher pull in solid blasting. The results of exploratory field trials of the use of spacer aided initiation technique in solid blasting with a specially developed Pentadyne-HP explosive conducted in an underground mine concluded that it was possible to achieve a pull of up to 2.2 m and yield up to 41 t per blast in a development face. Based on results of the studies conducted by authors, statutory authority for mines safety in India granted approval for commercial use of this technique with Pentadyne-HP explosive in all the degree I gassy underground coal mines.