A Comprehensive Roof Bolter Drilling Control Algorithm for Enhancing Energy Efficiency and Reducing Respirable Dust.

In underground coal mines, the drilling process in roof bolting operation could generate excessive amount of respirable coal and quartz dusts. Improper drilling control might also pose safety hazard and interrupt production. Therefore, an automated, high-efficiency drilling control system with safety features can be beneficial to the bolter personnel. In this research, a comprehensive drilling control algorithm has been developed to reduce the generation of respirable dust and to increase the drilling energy efficiency based on laboratory drilling test results and safety considerations. Specific energy is used to evaluate the energy efficiency. In addition, the ratio between specific energy and rock uniaxial compressive strength can be used as a basis for determining the rational drilling bite depth-typically a determined high one permissible by the driller power and drill steel. The test results show that to achieve and maintain a desired drilling bite depth for good drilling performance, a combination of relatively low rotational rate and a rationally high penetration is preferred. By monitoring the drilling rate, the system is able to evaluate the bit wear condition and improve drilling safety. In this paper, the developed drilling control algorithm for achieving a rational drilling bite depth is demonstrated. By adapting this drilling control algorithm, the drilling efficiency and bit condition can be monitored in real time, so the system can maintain a relatively high energy efficiency, generate less respirable dust, and avoid drilling failure.