217 underground chambers, where a pilot shaft serves as a slag chute, enabling rapid excavation via large-scale mechanical or blasting methods. (2) The primary constraint on gravity-driven slag removal drilling technology for large-diameter wells is geological conditions. It is suitable for stable rock formations. For water-rich, fractured, or karst-developed strata, pre-grouting modification is required for sealing and reinforcement. In weak, unstable, or water-bearing formations, ground freezing provides temporary stabilization to meet drilling requirements. (3) The advancement of mechanical rock-breaking drilling technology and equipment for large-diameter wells has accelerated underground mineral extraction and subsurface engineering in China. Gravity-driven slag removal offers significant energy-saving and cost advantages. Continued innovation in technology, processes, and equipment is essential to promote safer, greener, mechanized, and intelligent drilling systems, expanding their application in resource development and underground construction. ACKNOWLEDGMENTS The authors sincerely thank the collaborating authors, including Researchers Song Chaoyang, Cheng Shouye, and Jing Guoye, for their writing guidance and assistance in this study, and the collaborating institutions for providing professional platforms that have provided strong support for this research. REFERENCE Berlin:Ernst& Sohn (2008). Hardrock Tunnel Boring Machines. Berlin:Bernhard Maidl,LeonhardSchmid, Willy Ritz, et al. China Coal Industry Publishing House (2015). Research and Practice on the Support Structure of Well Shaft in Drilling Method for Well Construction. Beijing, China: Hong Boquan, Liu Zhiqiang, Jiang Haoliang. Chinese Journal of Geotechnical Engineering (1998). Time-space design theory for deep ice wall of short cylinder. Beijing, China: Chen Xiangsheng Coal Science and Technology (2021).Development history and status quo of raise boring technologies and equipment in China. Beijing, China: Liu Zhiqiang, Song Chaoyang, Cheng Shouye, et al. Coal Science and Technology (2022). Classification grading evaluation index system and evaluation method of surrounding rock for full section shaft boring machine. Beijing, China: Liu Zhiqiang, Song Chaoyang, Cheng Shouye, et al. Journal of China Coal Society (2005). Theory study on axial structural stability of bored shafts filled with water. Beijing, China: Niu Xuechao, Hong Boquan, Yang Renshu. Journal of China Coal Society (2020). Equipment and key technologies for full-section scientifically drilling of kilometer-level vertical shafts. Beijing, China: Liu Zhiqiang, Song Chaoyang, Cheng Shouye, et al. Journal of China Coal Society(2020).Technology and application of large curtain grouting water conservation mining based on macroscopic and mesoscopic characteristics of rock mass. Xi’an , China: Dong Shunying, Liu Zhaoxing, Zheng Shitian, et al.
RkJQdWJsaXNoZXIy MTM0Mzk2