1506 WORLD’S FIRST 10-METER FULLY MECHANIZED LONGWALL MINING IN EXTRA-THICK COAL SEAM: A CHINESE BREAKTHROUGH Hongpu Kang1, 2, Gang Xu2, Jinhu Zhang1, 2, Fuqiang Gao1,2 1State Key Laboratory of Intelligent Coal Mining and Strata Control, China Coal Research Institute, Beijing, China 2Coal Mining Research Institute, China Coal Technology and Engineering Group, Beijing, China ABSTRACT China has achieved a world-leading breakthrough in intelligent and efficient mining of ultra-thick coal seams by establishing and successfully operating the first fully mechanized longwall face with an unprecedented maximum shield height of 10 m. Led by China Coal Technology and Engineering Group (CCTEG) and Shaanxi Coal and Chemical Industry Group in collaboration with major equipment manufacturers, this pioneering project was implemented at the Caojiatan Coal Mine, Shaanxi Province, after nearly five years of intensive development. For the first time globally, a shearing height of nearly 10 m was achieved, enabling high-yield, high-efficiency, and high-recovery mining of extra-thick coal seams. Under challenging geological conditions characterized by thick and hard roofs and strong mining-induced stresses, a coordinated control strategy of “strong support combined with regional hydraulic fracturing,” a complete set of 10 m ultra-large hydraulic shields, shearers, and scraper conveyors, together with intelligent collaborative control and multi-parameter monitoring systems, were systematically developed and applied. This project represents a historic step from “large” to “ultra-large” shearer heights, driving substantial advances in ground control technology, high-capacity mining equipment, and intelligent mining systems. The successful implementation not only greatly enhanced recovery efficiency and economic benefits but also marked China as the first country to realize 10 m one-pass longwall mining on a production scale. This engineering achievement has set a new global benchmark in coal mining technology and provides a Chinese solution and experience for the safe and efficient extraction of ultra-thick coal seams, expected to exert a profound influence on future international mining practices. KEYWORDS longwall coal mining; ultra-thick coal seams; 10-m one-pass; ground control; miming equipment 1. INTRODUCTION Extra-thick coal seams (generally thicker than 8 m) are widely distributed in major coal-producing countries and constitute an important resource base for high-capacity and high-efficiency underground mining. In China, extra-thick coal seams account for more than 45% of total coal reserves and are concentrated in large-scale modern mining districts in western regions (National Bureau of Statistics of China, 2025). Efficient exploitation of these seams is therefore critical to long-term energy security and sustainable coal mine development. Fully mechanized longwall mining with large mining height has been widely recognized as an effective approach for extra-thick coal seams due to its advantages in production efficiency, coal quality control, and recovery rate (Wang et al., 2015). Over the past two decades, continuous progress has been achieved worldwide, and the maximum practical mining height has been gradually increased from approximately 6 m to about 8–9 m (Xu et al., 2022; Yang., 2017; Yang., 2019). However, further increasing the mining height beyond this range has long been regarded as technically prohibitive. The reasons include the rapid escalation of ground pressure intensity, severe instability of ultra-high coal walls, extreme loading demands on hydraulic shields, and the lack of reliable equipment capable of operating under such conditions. As a result, extra-thick coal seams with thicknesses around 10 m have traditionally been mined using layered mining or top-coal caving methods. These methods suffer from inherent limitations such as
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