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Design principles: In the design of long-distance belt conveyors, the principles of improving equipment reliability and reducing construction costs are followed. Factors such as topographical conditions, ease of installation, feasibility of maintenance, arrangements for power and water supply, as well as civil engineering requirements are also taken into account. Long-distance belt conveyors are generally installed in areas with gentle terrain, such as river valleys, avoiding villages, existing buildings, steep mountains, water bodies, and areas with poor geological conditions along the way. Efforts are made to minimize the use of arable land and to avoid damaging the local ecological environment. Most conveyor systems adopt a steel-structured overhead gantry format, spanning valleys, roads, rivers, and other facilities along their route. The overhead height of these gantries meets the specified clearance requirements, ensuring that they do not interfere with the construction of existing facilities or road traffic. The belt conveyor is sealed throughout its length with colored steel plates, ensuring that the material is not transported exposed; it is thus unaffected by weather conditions such as rain, wind, and snow, which helps to prevent dust and noise pollution. The conveying system includes transfer stations, drive stations, and substations, which are located as close as possible to highways and near their intersections with existing roads, facilitating installation, transportation, and routine maintenance. Design considerations 2.1 Selecting a suitable buffer receiving device: It is necessary to take measures to ensure the service life of the belt in long-distance belt conveyors, and reducing impact and wear on the belt is a key measure for this purpose. Belt conveyors experience significant impacts at the material receiving point; therefore, reasonable techniques and methods must be employed in their design to reduce the impact on the belt. This involves not only reducing the height difference of the falling material but also using appropriate buffering devices. The most advanced and suitable solution at present is the integrated cushioned receiving device with supports, which combines the advantages of cushioned idlers and a cushioned bed. In general, the spacing between buffer idlers is set at around 400 mm. The conveyor belt runs suspended between two buffer idlers. In this situation, the impact of materials can cause significant damage to the belt. This is especially true for materials with large sizes and sharp edges, or for sharp foreign objects such as iron spikes or liner plates; once these fall onto the belt between the two idlers, they can pierce or cut through it. If not addressed promptly, this can result in the belt splitting into two pieces—a fatal form of damage for large steel cord conveyor belts. To this end, a rigid support plate has been designed between each buffer idler; under normal operation, the conveyor belt does not come into contact with this plate. However, when large pieces of material or foreign objects strike the belt, the belt deforms under the force and comes into contact with the rigid support plate, which then bounces back the material and metal objects, thereby preventing them from scratching the belt. 2.2 The tube formation and unfolding of tubular belts must adhere to the principle of graduality. The transition section where the conveyor belt changes from a flat shape to a cylindrical tube must also follow this principle. The length of the transition section is primarily determined by the allowable elongation rate of the conveyor belt and the requirement that the material be gradually rolled into the range of the circular pipe. In the transition section, the conveyor belt changes from a flat shape to a circular tube, resulting in significant additional deformation at the edges of the belt. The elongation strain at these edges can be calculated in a similar manner to that used for the transition sections of trough-type conveyors. Generally, the length of the transition section can be taken as 25 times the diameter of the circular tube. 3. Select an appropriate conveyor belt cleaning device. Generally, the cleaning devices used for belt conveyors include scraper cleaners, roller-type cleaning devices, brush-type cleaning devices, vibration cleaning devices, water sprayers, and wiper cleaners. A choice can be made based on the actual circumstances. 4. Inversion of the conveyor belt: Flipping and cleaning the conveyor belt is a fundamental measure to prevent blockages in the space beneath the conveyor belt as well as to stop materials from sticking to the idler rollers. This method uses guide idlers to flip the return conveyor belt at the end of the conveyor by 180°, so that its clean side comes into contact with the lower idlers. This prevents materials from sticking to the idlers and from spilling along the conveyor line, reduces wear on the conveyor belt and idlers, and improves the utilization rate of the conveyor belt’s cover layer. The setup of the tape flipping device ensures that the carrying side of the tape always remains on top; this prevents any materials adhering to the tape from falling off during operation, thereby avoiding contamination along the conveyor line ； Secondly, it reduces the mutual wear between the tape’s load-bearing surface and the return idlers, thereby extending the service life of both the idlers and the tape. While extending the service life of the tape equipment, it also reduces power consumption, embodying the design concept of energy conservation and consumption reduction. The main methods of conveyor belt flipping include: free flipping, forced flipping, directional flipping, and tubular flipping. The first two methods are suitable for conveyors with narrower widths, while the latter two are applicable to conveyors of any width and are widely used in long-distance belt conveyors. Depending on the strength of the conveyor belt, the turning length of a canvas-core conveyor belt is 8 to 12 times the belt width, while that of a steel-cord core conveyor belt is 15 to 25 times the belt width. 5. Install necessary mechanical and electrical protection devices. Belt conveyors operate properly under the protection of such devices, which safeguard the main components of the conveyor in the event of an accident. (1) Deviation prevention protection device. For long-distance belt conveyors, in addition to installing self-aligning idler sets and properly arranging forward-inclined side idlers, an appropriate number of automatic deviation correction devices should be selected based on the length and overall layout of the conveyor. With the development of belt conveyor technology, there are now various types of automatic deviation correction devices; one can select the most suitable device based on its cost and effectiveness. (2) Belt speed detection protection device. Optical encoders are the preferred choice for detecting the belt speed of long-distance belt conveyors. Speed protection devices can be selected as tachogenerator-type protection devices, magnetic induction transmitter-type protection devices, or proximity switch-type speed protection devices. (3) Breakband protection device. To prevent the conveyor belt from sliding down after it breaks, a catcher must be installed for belt break protection. The choice of catcher should ensure rapid response, along with the shortest possible braking time and braking distance. Furthermore, when the conveyor is operating normally, it does not wear out the conveyor belt, does not generate additional resistance, and does not reduce the conveyor’s productivity. The reliability of the catcher is not affected by the level of material filling on the conveyor belt or the installation inclination angle of the conveyor. The most commonly used ones are wedge traps and roller traps. (4) Metal debris detection and removal device. Currently, metal detectors and iron removal devices are mainly used. Iron removal devices include belt-type iron removers and suspended electromagnetic iron removers. (5) Longitudinal tear protection device. The anti-tear protection device for conveyor belts includes two types of detection methods: detecting changes on the outside of the conveyor belt after a tear occurs, and detecting changes in its internal condition. 6. Arrange planar turns reasonably according to the terrain and topography. For long-distance belt conveyors, planar turns are essential depending on the terrain and the distribution of obstacles; the core of planar turn design lies in the design of tension and turning measures. The key design aspects include the following: (1) The layout design of the conveyor, during which the radius of curvature of the curved sections of the conveyor is initially determined based on the topographical conditions of the area where the equipment will be installed ； (2) Initially select the turning measures and the corresponding parameters for the idler sets; the groove angle of the idler sets should be between 25° and 55°, the elevation angle of the inner curve should be less than 5°, and the inclination angle of the idlers should be between 1° and 2°. The idlers should be arranged with their fronts tilted forward, in order to help prevent the conveyor belt from drifting ； (3) Calculate the tension at each point; in the turning section, calculate the resistance and tension in the curved section ； (4) Verification of the turning restriction conditions for the curved section ； (5) Belt conveyors are generally used for long-distance mainline material transportation. A detailed dynamic analysis of them is required, and this result should be used to further verify the turning limit conditions ； (6) Add protective measures to ensure the conveyor operates during turning. 7. Select a reasonably energy-efficient drive unit. In addition to fulfilling the normal operating functions, the drive unit for belt conveyors must also meet energy-saving requirements. The drive design for long-distance belt conveyors takes the following aspects into consideration: (1) The drive unit should have good starting performance, with a large starting torque to enable the conveyor to start under load ； (2) It has a sufficiently small and reasonable acceleration during startup to reduce the dynamic loads on various load-bearing components. (3) Multi-motor drive enables even load distribution among the motors ； (4) Reliable overload protection during the startup and stable operation phases ； (5) The drive unit offers good controllability, enabling control of the speed as well as the acceleration and deceleration during startup and shutdown ； (6) Try to start the motors under no-load conditions, stagger the starting times of various motors, and reduce the number of times motors are started; this way, it is not necessary to shut down the motors when the conveyor stops for a short period of time ； (7) The drive unit shall include a controller with self-monitoring and self-diagnosis functions ； (8) Use controllable start/stop drive devices as much as possible.