The hoist cage of a mine is the "artery" of the mine, performing core functions such as personnel lifting, material transportation, and equipment lowering. With the advancement of smart mine construction, the electrical equipment on the hoist cage is increasing - from lighting, voice intercom, to automatic barrier devices, cage curtain doors, as well as video surveillance and personnel positioning devices. However, how to supply power safely and stably to these devices has become a headache for mine managers.

Two Old Paths: The "Dead End" of Cable Dragging and Battery Power Supply

The traditional power supply solutions for mining cage systems mainly include two methods: cable dragging and battery power supply. However, both of these "old paths" are becoming narrower and narrower.

The cable dragging solution was once regarded as the "standard answer" for cage power supply - dragging a running cable along the cage to supply power to auxiliary equipment. However, this solution has exposed risks in practice. The depth of the mine is often several hundred meters, and the cage runs back and forth hundreds of times every day. The cable is prone to wear and tear due to long-term bending, stretching, and friction, which can easily cause signal interruption, or even lead to power leakage and electric shock, or even trigger electrical sparks.

The practice of Luanan Chemical Industry Yuwu Coal Mine revealed the deep pain points of the cable dragging solution: The auxiliary hoist of the secondary shaft of this mine has a running height of 558.9 meters. The power supply line needs to be transported over a long distance, involving various safety configurations such as explosion-proof measures, grounding protection, and overload protection. In addition, since the auxiliary devices of the cage are located at a high altitude, it is extremely difficult to maintain and repair the power equipment - the power system needs to have sufficient protective capabilities to cope with adverse factors such as humidity, corrosion, and vibration in the underground environment, while also meeting the requirements of easy maintenance.

The battery power supply solution is another "bumpy path". Using battery power supply eliminates the need for cable dragging, but it brings the burden of frequent battery replacement. The experience of Guoshen Company's Huangyuchuan Coal Mine is the most typical: In the project of the automatic stopper device in the large cage hoist, due to the use of pure battery power supply, the mine needed to keep spare batteries on hand, and had to replace the batteries every 7 to 8 days, with up to 4 replacements per month. The battery replacement process is complicated, and frequent disassembly and assembly also led to loose screws on the explosion-proof shell of the battery and loose power connectors. More seriously, if the battery is not replaced in time, a sudden power outage during operation will directly affect the operation of the stopper device, causing obstruction in the loading and unloading of materials in the cage.

The deeper hidden danger lies in safety. High-altitude disassembly and assembly of batteries in a 600-meter deep mine shaft is itself a high-risk operation - it may cause falling objects to injure people, or even cause the operator to fall into the mine shaft. This already violates the safety concept of "fewer people is safer, no people is safer" in mines.

II. Pain Points Escalate: How Traditional Power Supply Constraints the Construction of Smart Mines

In 2025, the market size of China's mine hoist industry is approximately 13.2 billion yuan, with coal mine hoists accounting for over 70% of the total. Within this vast existing market, the power supply issue for cage transportation is evolving from a "technical problem" to a "strategic problem".

On one hand, the functions of the cage are constantly expanding. After the first "smart" cage was put into use by Kailuan Group, the chief engineer of the Electrical and Mechanical Department, Ma Hongjun, expressed the hardships of the research and development process: "The cage is a long-distance moving device. To add functional accessories, the two major problems of power supply and signal transmission must first be solved." In the construction of smart mines, the cage is evolving from a simple tool for transporting people and goods to a comprehensive system integrating intelligent monitoring, real-time communication, safety warning, and automatic control. The stability and reliability of the power supply system directly determine whether these intelligent functions can be truly implemented.

On the other hand, the policy requirements for mine safety continue to tighten. In January 2026, the National Mine Safety Supervision Bureau proposed to promote the engineering trial of safe mining in deep coal mines. In March of the same year, the National Mine Safety Supervision Bureau released the "Key Research and Development Catalogue for Mine Intelligent Robots", proposing 7 major categories and 56 types of research and application directions for mine intelligent robots, aiming to promote the substitution of robots for dangerous, tiring, arduous, and dirty positions in mines. Shandong Province has clearly stated that by 2026, provincial-owned and some municipal-owned coal mines will complete the construction of artificial intelligence scenarios in key areas, and by 2027, the proportion of intelligent mining output in the province will reach over 95%.

Under this background, the wireless and maintenance-free power supply methods for the cage have not been a "choice question", but a "must-answer question" for the construction of smart mines.

III. Solution to the Problem: WIRELESSPT Wireless Charging Solution for Mine Cage

Facing the dual challenges of cable wear and frequent battery replacements, WIRELESSPT has launched a wireless charging solution specifically designed for the mining cage scenario. This solution is based on the principle of magnetic resonance coupling. The transmitting end is installed at a fixed position on the derrick, while the receiving end is integrated into the cage. By taking advantage of the brief window each time the cage stops at the wellhead or bottom, it can complete non-contact automatic charging, truly achieving "stop and charge, use on the go".

Full power matrix, precisely matching different cage requirements. For cage equipment with different tonnage and power consumption, WIRELESSPT provides three power levels of wireless charging products: 600W, 900W, and 1200W. The output voltage covers 24V, 36V, and 48V, and the output current is all 20A. The 600W series is suitable for lighting and barrier device power supply for small cages, the 900W series can meet the comprehensive power consumption of medium-sized cage lighting, monitoring, and intercom systems, and the 1200W series provides sufficient energy for large-capacity equipment such as video surveillance and personnel positioning in large cages.

High offset tolerance, reducing positioning accuracy requirements. In actual operation, it is difficult for the cage to achieve a completely consistent stop position each time. The WIRELESSPT wireless charging system has excellent anti-offset capability: for the 1200W product, the X-axis (long axis) horizontal offset tolerance is ±110mm when the vertical distance is 40mm, and the Y-axis (short axis) is ±10mm. This means that even if there is a certain deviation in the stop position of the cage, the system can still stably and efficiently transmit electrical energy, without the need for high-precision alignment.

Fully sealed and highly protected, suitable for harsh underground environments. The mine environment is humid, dusty, and there is water leakage, which places extremely high requirements on the protection level of electronic equipment. The receiver of the WIRELESSPT cage wireless charger has a protection level of IP67, and the transmitter has an IP65 protection level. It can completely prevent dust from entering and withstand short-term water immersion. The working temperature range covers -40℃ to +60℃, adapting to extreme temperature changes in the underground environment.

Multiple intelligent protections ensure absolute safety. The system is equipped with three-layer protection mechanisms of over-temperature, over-current, and over-voltage. When the temperature reaches 82℃, it automatically reduces power or stops. It supports two startup modes: 485/CAN command wake-up and "near and charge" for automatic operation without manual intervention, fundamentally eliminating the risks of manual plugging and high-altitude operations. The maximum transmission efficiency under full load can reach over 92%, far exceeding the industry average.

IV. The Choice of the New Era: Eliminating the "Safety Shortcoming" of Crawler Cage Power Supply

As the intelligentization construction of mines enters an accelerated phase, the upgrading of the power supply method for the crawler cage, which serves as the core node for personnel and material transportation, is an inevitable necessity. From the wear risk of the cable to the safety hazard of battery replacement at heights, the fundamental problem with the traditional solution lies in: they have turned "power supply" into an operation that requires continuous manual intervention.

WIRELESSPT offers a different approach - converting the power supply system into an automated device that does not require manual intervention. By taking advantage of the natural stopover window of the crawler cage, wireless charging can be achieved with "stopover for charging, use while moving", which is not only a technical replacement for the traditional charging method but also a reconfiguration of the underground operation mode.

In mines where "safety is the primary benefit", making the power supply of the crawler cage no longer a safety shortcoming - this might be precisely the most valuable aspect of wireless charging technology that deserves the industry's attention.