Effects of proper drilling control to reduce respirable dust during roof bolting operations

Abstract

Dust generated from bolt hole drilling in roof bolting operation could have high quartz content. As a dust control measure, vacuum drilling is employed on most of the roof bolters in US underground mines. However, fine rock particulates from drilling could escape from the dust collection system and become airborne under some circumstances causing the roof bolter operators expose to quartz-rich respirable dust. A previous research shows that drilling can be controlled through properly selected penetration and rotational rates to reduce the specific energy of drilling. Less specific energy means less energy is wasted on generating noise, heat and over-breakage of rock. It implies that proper control of drilling has a great potential to generate significantly less fine rock dust during drilling. The drilling experiments have been conducted to study the effect of controlling drilling on reducing respirable dust. The preliminary results show that the size distributions of respirable dust were different when controlling drilling in different bite depths. This paper presents the findings from laboratory experimental studies.