At dawn, at the auxiliary shaft entrance of the Xinzhuang Coal Mine in Gansu’s Ningzheng Mining Area, a 48-ton heavy-duty rubber-tired flatbed vehicle smoothly rolls into a 55-ton metal cage. Accompanied by a low hum, the cage descends steadily at 40 km/h to a depth of 1,024 meters underground—just another routine operation of the auxiliary vertical shaft hoisting system designed by Beijing Huayu, a subsidiary of China Coal Technology & Engineering Group (CCTEG). Dubbed a “super elevator,” this system centers on “heavy-load, high-efficiency” transportation: it can not only transport large mining equipment in a single trip but also carry up to 240 miners at once, providing robust support for safe and efficient operations at kilometer-deep working faces.

Approved by China’s National Development and Reform Commission (NDRC), the Xinzhuang Coal Mine is a key project within the Ningzheng Mining Area, with an annual production capacity of 8 million tons and a designed service life of 81.7 years. It serves as a cornerstone of China Huaneng Group’s “Northern Corridor” strategy. The auxiliary shaft has a diameter of 9 meters and reaches a depth of 1,024.3 meters—equivalent to a 300-story skyscraper.

“Building a ‘super elevator’ in such an ultra-deep shaft requires more than just safely transporting personnel—it must also handle heavy vehicles and massive equipment with exceptional stability,” said Shi Xiaoyong, Dean of Beijing Huayu’s Smart Mining Institute. “This demands us to break from conventional thinking and achieve comprehensive innovation in equipment design, control systems, and safety mechanisms.”

Technical Breakthroughs: Three Pillars of Safety
1. Anti-Off-Center Loading: Keeping 48-Ton Loads Rock-Solid

To address off-center loading during hydraulic support lowering, the design team developed a “Triple Center Alignment” solution. Using a self-developed heavy-duty rubber-tired flatbed, they aligned the centers of gravity of the equipment, vehicle, and cage—eliminating uneven stress on guide rails and ensuring smooth, high-speed hoisting. “It’s like a precision balance—when all three centers align, the off-loading problem vanishes,” explained An Chunping, the project’s lead engineer. Since commissioning, guide rail wear has decreased by 10%, and the service life of roller guides has significantly increased.

2. Dual Safety Nets: Securing 240 Miners in One Trip

With a single-trip capacity equivalent to two Boeing 737 aircraft, the system sets an industry benchmark for personnel hoisting safety. Its electrical and hydraulic systems employ a “mutual monitoring” logic: if the hydraulic station malfunctions, power isn’t cut; instead, the heavy cage is slowly lowered to mitigate risk. Two independent hydraulic stations serve as backups for each other, enabling seamless takeover during extreme failures. Coupled with vibration-dampening technology, the dual constant-deceleration hydraulic system precisely controls emergency braking deceleration to 1.5–1.6 m/s², effectively suppressing elastic vibrations in the hoist ropes during acceleration/deceleration. “Now going down the shaft is fast and smooth—no more ear-popping!” remarked miner Master Li with relief.

3. Energy-Saving Shield: Saving Over 2.8 Million kWh Annually

The system innovatively adopts a “fixed counterweight + movable trolley” structure. During normal operation, the trolley is disengaged to reduce tension differences in the hoist ropes and lower energy consumption. Real-world measurements confirm annual electricity savings exceeding 2.8 million kWh. Additionally, a variable-frequency drive system—paired with reactive power compensation and harmonic mitigation devices—maintains a power factor above 0.9, establishing a new green, low-carbon model for deep-shaft hoisting.

Localization Breakthrough: Half the Cost, Equal Performance, World-Class Quality
“In the past, similar equipment relied almost entirely on imports, driving costs sky-high,” revealed a Xinzhuang Coal Mine official. Beijing Huayu actively promoted localization: core components like the 6.2-meter-diameter hoist and motor are now domestically produced, with only a few parts—such as bearings and lining pads—still imported. While the main inverter remains imported, the entire control system is fully localized. Through rigorous oversight during manufacturing, the team ensured performance and reliability matched that of fully imported systems—at just 50% of the cost—saving RMB 276.37 million in construction investment and accelerating the advancement of China’s domestic mining equipment industry.

Benchmark Leadership: Excellence in Technology and Talent
The Xinzhuang auxiliary shaft hoisting system has earned one national and three ministerial/provincial awards. Notably, it was the only individual coal engineering design project to win the 2025 National Excellent Engineering Survey and Design Award (Second Prize). Leveraging this project, Beijing Huayu collaborated with top universities on the “Core Technology R&D for Safe Mine Hoisting Operations,” establishing theoretical models and design methodologies for off-center load dynamics, wire rope failure mechanisms, and fault-state simulation—creating replicable technical solutions. The project also cultivated over 20 specialized technical experts, driving industry progress through dual engines of innovation and talent development.

Unlocking Deep Resources: A Key to Trillion-Ton Reserves
Estimates indicate China holds approximately 5.57 trillion tons of coal resources within 2,000 meters of the surface—nearly half (47.4%, or 2.64 trillion tons) lying deeper than 1,000 meters. As shallow reserves dwindle, “mining deeper” has become essential for national energy security. “The Xinzhuang auxiliary shaft hoisting system provides a replicable technical blueprint for heavy-duty, kilometer-deep mine hoisting,” noted Li Yujin, an expert from the China National Coal Association.

As the cage ascends gently to the surface, sunlight bathes the smiling faces of miners. The steady hum of this “super elevator” marks the opening movement of China’s coal industry symphony—venturing deep underground, where vast “energy treasures” await awakening.