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A design concept for hoisting containers in ultra-deep wells was proposed; based on the relevant well layout and parameters, the cross-section of the hoisting container as well as the selection and design of its various components were determined. To meet the requirement of loading different ores at various loading points within the same well and discharging them at different levels, a multi-point loading and multi-point discharging system was developed. The successful application of lifting containers in ultra-deep wells can provide guidance or reference for the design of such containers in deep or ultra-deep wells in the future. With the economic development of human society, demand for various mineral resources continues to rise, leading to the ongoing exploitation of shallow mines and a corresponding decrease in shallow mineral resources. Our country is a major holder of mineral resources as well as a country with high demand for them; therefore, the development of mineral resources should focus on deeper mining operations, which has led to the creation of specialized equipment for extracting minerals from deep underground. To ensure the safe and efficient extraction of mineral resources, the design and development of lifting containers for deep or ultra-deep wells is essential. Lifting containers for wells with a depth of less than 800 meters are considered shallow or medium-deep well lifting containers; those for wells with a depth exceeding 800 meters are known as deep well lifting containers, while those for wells with a depth of 1,500 meters or more are referred to as ultra-deep well lifting containers. Compared to lifting containers for shallow or medium-deep wells, ultra-deep well lifting containers feature lower self-weight, higher terminal load capacity, and greater strength. Shaft No. 3 of Yunnan Chihong Huize Mining Branch is a shaft designed for exploring resources in the deeper parts of the mine; its depth reaches 1,526 meters, making it the second deepest shaft in Asia. It belongs to the category of ultra-deep mines, and the lifting containers used there can be referred to as ultra-deep mine lifting containers. 1 Improving the container and related parameters: The shaft diameter of Shaft No. 3 at Weize Mining Branch is 6.5 m, and the shaft is equipped with a hybrid lifting system that uses one skip in combination with one cage. The cross-section of the hopper is 1,940 mm × 20.0 mm, while that of the cage is 50.0 mm × 20.0 mm. The layout of the shaft is shown in Figure 1. The effective volume of the hopper is 13 m3, with a maximum loading capacity of 30.35 t and a weight of 38 t. The total weight of the 4 tail ropes is 118.39 t; therefore, the load at the end of the hopper is 186.74 t. The cage is lifted using a skip; its own weight is 38 t, and the total weight of the 4 tail ropes is 118.39 t. The cage features a double-layer structure. http://www.yuyin.sh.cn/images/UploadFile/2021520153240752.jpg Figure 1: Layout of the vertical shaft. To facilitate the lowering of long items and large objects, the middle platform in the cage is designed to be removable; once this middle platform is removed, the net height inside the cage reaches 6.1 m ； A movable counterweight vehicle is installed on the lower part of the cage, with a mass of 15.175 t. During normal lifting in the hopper, a counterweight vehicle enters the lower part of the cage to serve as a counterweight ； When lifting people in the cage, the counterweight vehicle moves away from the cage; at the same time, the hopper is not allowed to lift ore – it is used only as a counterweight. The cage is permitted to carry a maximum of 80 people per lift, across 2 floors. 2 Structural Analysis and Selection of Components 2.1 Selection of the main rope suspension device: The bucket is lifted using 6 main ropes. Due to the large terminal load of the hopper (the highest among the lifting containers in use in China at present), and the requirement for a low self-weight of the hopper, it is not advisable to use oversized main rope suspension devices. Large-sized suspension devices also have a large weight, which can affect the design of the hopper itself; it is sufficient to meet the required specifications, and for this hopper, the XSZ-400 (modified) type of suspension device has been chosen. The XSZ-400 (modified) suspension device was specifically redesigned based on the XSZ-400 model for the company’s No. 3 shaft. Since shaft No. 3 is an ultra-deep mine, the elongations of the 6 lifting steel cables are not uniform, requiring a large adjustment range. During the design modification, while maintaining the original failure load and basic functional principles of the suspension system, the adjustment height was increased from 933 mm to 1,200 mm, meeting the operational requirements. The XSZ-400 type suspension device is a mature product designed, manufactured, and applied by Xuzhou Coal Mine Safety Equipment Manufacturing Co., Ltd. It is a practical new-type product developed to address the issue that hydraulic pad-type rope adjusters commonly used at home and abroad are unable to automatically adjust the tension balance of steel cables. This device features a closed-loop, passive hydraulic connection system for automatic balance adjustment, which enables high-precision automatic balancing of the tension in the wire rope in both static and dynamic conditions. This ensures even stress distribution on the lifting container, reduces the impact of the container on the guide rails, and thus guarantees efficient operation of the hopper within the shaft. The design failure load for a single suspension unit is 40.0 kN, while the total failure load for 6 units is 240.0 kN. The maximum static load is 24,000.0 kN ÷ 10,240.0 kN (≈245 t) > 186.74 t, meeting the safety factor of 10 specified in the Coal Mine Safety Regulations. The selection of the main rope suspension device for the cage is the same as that for the hopper. 2.2 Selection of tail rope suspension device: The XWB-400(B) type is selected for the bucket tail rope suspension device; this suspension device was also designed specifically for Well No. 3 at Huize Mine. The failure load for a single set of this design is 40.0 kN, while the total failure load for 4 sets of tail rope suspension devices is 160.0 kN. The maximum static load is 16,000.0 kN ÷ 10,160.0 kN (≈163 t) > 118.39 t, meeting the safety factor of 10 specified in the Coal Mine Safety Regulations. The selection of the tail rope suspension device for the accompanying cage is the same as that for the hopper. 2.3 Selection of the roller ear device: The hopper uses 2 square steel guide rails with a diameter of 220 mm, and its operating speed exceeds 13 m/s. Due to the deep shaft, high assembly quality of the cage track is required to reduce the impact exerted by the bucket during operation. This hopper is equipped with 4 sets of LS35 type roller lugs. This roller lugs assembly is equipped with a buffering mechanism that uses disc springs for cushioning, and the buffering force can be adjusted ； The roller is made of polyurethane, which allows for adjustment of the cushioning force, thereby effectively reducing the impact of the hopper on the conveyor track during operation. The base of the roller luffing device is welded to the upper and lower parts of the hopper frame; the rotating wheel of the roller luffing device itself can be adjusted relative to the base. By making adjustments, the rotating wheel can be pressed against the rigid tank track, allowing the hopper to move up and down along the steel tank track via the rotation of the roller luffing device. The cage adopts a layout with steel guide rails on both sides, with 2 square steel guide rails of 220 mm each side; therefore, 8 sets of LS35 type roller shoe assemblies are used for the cage. 2.4 Body Structure and Connections: The bucket body adopts a frame structure combined with a rotating bucket box for ore discharge. Due to the large load at the bucket tip, the bucket frame and the main suspension plate are connected using 48 M30 grade 10.9 threaded socket head bolts, while the tail rope suspends the suspension plate with 40 bolts of this type. The assembled cage has large external dimensions, and due to geographical constraints, it cannot be transported; therefore, the cage is shipped in separate parts and assembled on-site at the wellhead, with the various components connected using 10.9 grade high-strength bolts. The main column and the upper housing are connected by 64 high-strength bolts of grade 10.9, with a diameter of M30. The tensile force acting on these bolts is given by http://www.yuyin.sh.cn/images/UploadFile/2021520153227531.jpg. In this formula, n represents the number of bolts, and n=64 ； μ is the anti-slip coefficient of the friction surface, μ=0.55 ； k is the shear connection coefficient, k=0.3 ； p is the pre-tension force of the high-strength bolt, p=335 kN. Calculations show that F=3537.6 kN (≈361 t) > 186.74 t. 3 Result Analysis (1) The hopper employs a dual-unloading system; two unloading stations are installed in the shaft. Station No. 1 is located at a depth of 1,810 m and is used for unloading the mixed ore, using movable straight rails for this purpose ； Unloading Station No. 2 discharges oxidized ore and waste rock at a level of 2,400 m, using fixed curved tracks for unloading. The hopper uses three-point loading: Loading station No. 1 is at 1,554 m, Loading station No. 2 is at 1,244 m, and Loading station No. 3 is at 894 m. (2) The use of two discharge points in the same hopper for ore discharge is a first in China; the No. 3 shaft at Huize Mine is currently the only mine in operation with dual discharge points. In ordinary mines, one shaft is equipped with one ore discharge point; for multiple horizontal levels requiring multi-point ore discharge, several shafts usually need to be dug. To ensure the smooth operation of the multi-point ore unloading function, the positioning accuracy deviation of the movable straight rails must not exceed ±5 mm, and it must also meet the requirements related to the normal elastic deformation and stretching of the steel wire ropes during unloading. Multi-point ore unloading saves a significant amount of cost in mining operations; the mobile straight-rail unloading device is shown in Figure 2. Figure 2 Mobile straight rail unloading device: The mobile straight rail is installed on the shaft casing beam and supported by rollers; these rollers are equipped with lubrication nozzles, while the straight rail is driven by hydraulic cylinders. When Unloading Station No. 1 is not in operation, the distance between the moving straight rail and the hopper must be at least 150 mm as required by the Coal Mine Safety Regulations, to ensure that the hopper can pass through at full speed. Both the straight rail and the skip must be equipped with detection switches that indicate whether they are fully opened or closed. The protection rating of these detection switches must be no lower than IP67. The unloading straight rail must ensure that the driven skip can be unloaded and closed accurately, without any secondary movements occurring. The unloading control system is equipped with a local console that enables manual, automatic, and remote control, as well as monitoring and display of operational parameters. It is also required that the unloading control system be able to transmit data accurately to the main hoist interface, thereby enabling fully automatic interlock control. 4 Conclusion In the future, deep-resource extraction technologies will be the direction for mining in China. The successful application of large-scale ultra-deep well lifting containers and dual-unloading equipment in Well No. 3 of the Huize mine provides valuable experience for the design and selection of lifting containers in deep-well mining in China. The development and use of dual-unloading equipment have improved the economic efficiency of mining operations.