Objective  For deep mining of coal mines, conventional directional drilling rigs face challenges including high labor intensity, limited control accuracy, a low intelligence level, and failure to meet the demand for efficient gas drainage. Meanwhile, high-power automatic drilling rigs encounter technical bottlenecks in automation, control accuracy, and process intelligence in this context. To address these issues, this study proposed an integrated and systematic solution—the ZDY15000LDK high-power automatic directional drilling rig.

Methods  Using a compact structural layout, a drill rod handling system was developed, consisting of a drill rod loading/unloading manipulator with four degrees of freedom and an automatic drill rod storage and transport system. Accordingly, the continuous automatic loading/unloading of heavy directional drill rods, along with the reduction in the number of operators per duty shift, were investigated. Using a modularized hydraulic control system and a proportional valve-based closed-loop electronic control strategy, a model for a precise match between drilling conditions and control parameters was established, followed by the analysis of the response speed and dynamic stability of the drilling rig system. A series of intelligent process algorithms based on measurement-while-drilling (MWD) data were developed for automatic toolface angle adjustment, automatic drilling of borehole branches, and closed-loop borehole trajectory control. On this basis, a model for autonomous decision-making and real-time deviation correction in the drilling process was established, and the method for high-precision control of directional drilling under complex operating conditions was explored.

Results and Conclusions  In the field tests on crushed soft coal seams in the Luotuoshan Coal Mine in Wuhai City, a directional borehole with a depth of up to 621 m was successfully drilled using the ZDY15000LDK high-power automatic directional drilling rig, with an increase of over 50% in construction efficiency, trajectory deviation errors controlled within 1 m, and tool face angle accuracy of ±0.5°. These results verify that the drilling rig delivers the technical advantages of efficient, precise, and minimally manned drilling in complex coal seams. Through structural integration innovation, the collaborative optimization of electro-hydraulic control systems, and the fusion of intelligent process algorithms, the proposed solution effectively addresses the challenges that conventional high-power directional drilling rigs tend to face in deep complex strata, such as a low degree of automation and limited control accuracy. Therefore, the proposed solution provides a key technical pathway for the research and development of equipment for intelligent underground drilling in coal mines.