A control system for optimizing deep hole drilling conditions

An instrumentation and control system has been designed for monitoring and controlling the parameters which determine the performance of a deep hole diamond drill. Bit performance in terms of average penetration rate and life has become extremely important because time-dependent costs have become the major proportion of the total costs per meter drilled due to the deep holes encountered especially in the gold exploration drilling industry. The authors define and discuss the important parameters influencing the drill bit performance. An analysis and simulation done on an assumed model indicated that stable, well-damped, closed-loop control could be maintained over the wide range of system dynamics expected to be encountered in the system. The results obtained so far in terms of the average penetration rate are very promising compared with results obtained prior to implementing the instrumentation and control system. Preliminary results indicate average penetration rates up to 100 m for a 24-h period compared to previous rates of some 50 m for the same period