Stage Transport Roadway Layout Forms and Their Engineering Applications

I. Core Principles for the Layout of Stage Transport Roadways

(1) Design for the Compatibility Between Mining Methods and Production Capacity

The arrangement of stage haulage roadways is closely and inextricably linked to the mining method employed, directly influencing the overall efficiency and profitability of mine operations. Take the open-stope mining method as an example: when the ore body is small in scale and has a relatively steep dip angle, placing the stage haulage roadway outside the vein is often a common and rational choice. Under this arrangement, driving upward cut-throughs effectively connects with return air drifts, thereby establishing comprehensive ventilation and transportation pathways that provide a solid foundation for the smooth execution of mining activities. In a real-world mining scenario, a small gold mine adopted the open-stope method, where the ore body exhibited a steep dip angle of 70° and was relatively small in size. After thorough geological surveys and technical evaluations, the stage haulage roadway was strategically positioned outside the vein, utilizing upward cut-throughs to link seamlessly with the return air drift. As a result, ventilation remained unobstructed, ore transportation became highly efficient, significantly boosting mining productivity while simultaneously reducing production costs.

From the perspective of production capacity, the layout of stage transport roadways must align with the mine's annual output to ensure that transportation efficiency meets the demands of mining operations. For mines with annual production ranging from 200,000 to 600,000 tons, a dual-track crossover arrangement along the ore vein is an especially suitable option. This layout features two parallel tracks within the roadway, connected at strategic points via crossovers, significantly enhancing the overall throughput capacity and effectively accommodating the production scale and transportation needs of such mines. Meanwhile, when a mine’s annual output increases to between 1.5 million and 3 million tons—and particularly when dealing with thick ore bodies—adopting a circular layout consisting of upper and lower level cross-cut roadways combined with transverse drifts proves even more advantageous. This circular configuration creates a highly efficient transportation network, enabling rapid movement and turnover of ore while ensuring seamless alignment between transportation speed and mining rhythms, thus perfectly supporting large-scale production requirements.

(2) Multi-dimensional Determination of Tunnel Cross-Section Parameters

Determining the dimensions of a tunnel cross-section is a complex process that requires careful consideration of multiple factors to ensure the tunnel meets various requirements, including equipment passage, route layout, ventilation needs, and throughput capacity. In the arrangement of trackless equipment tunnels, the angle between the ore-drawing access route and the ore-discharging tunnel is a critical design factor. Generally speaking, setting this angle around 45° is ideal. Additionally, the length of the ore-drawing access route should be no shorter than the body length of the loader. Such a design effectively guarantees the loader’s safety and efficiency during operation, preventing potential issues like equipment collisions or operational inefficiencies caused by an excessively small angle or an overly short access route.

Ventilation requirements are another critical factor in determining the cross-sectional dimensions of roadways. In the mining operations of both metallic and non-metallic mines, it is essential to strictly adhere to the wind speed limitations outlined in the "Safety Regulations for Metallic and Non-Metallic Mines." Based on the airflow balance equation, we can calculate the minimum required cross-sectional area of the roadway by working backward from known parameters such as the total intake air volume, the ventilation demands at individual air consumption points, and the overall ventilation resistance. Specifically, if we know these factors, we can use the formula—where represents airflow, represents wind speed, and represents cross-sectional area—to determine the smallest area that meets the ventilation needs. Insufficient roadway cross-sections, however, may lead to stagnant, contaminated air that cannot be efficiently expelled, thereby compromising the air quality in the underground working environment and posing serious health risks to miners. Moreover, poor ventilation conditions could even trigger safety incidents. For this reason, when designing roadway cross-sections, it is crucial to thoroughly account for ventilation requirements, ensuring that the tunnels provide adequate space to maintain proper airflow and guarantee the smooth operation of the underground ventilation system.

II. Typical Layout Forms and Their Engineering Application Scenarios

(1) Single along-mine-roadway layout

1. Single-line push-type

The single-track passing-type along-mine-roadway layout is suitable for thin to medium-thick ore bodies, typically those with a thickness of less than 15 meters. In this arrangement, transportation roadways usually feature single-track rails, except at passing stations. During actual transportation, loaded vehicles are given priority, while empty vehicles must wait at passing stations to allow the heavier loads to proceed first, ensuring an orderly flow of traffic. However, this layout has relatively limited throughput capacity—roughly 10 to 20万吨 per year—mainly due to the constraints imposed by the single-track system, which somewhat reduces the efficiency of vehicle movement.

However, the single-track let-off layout also offers several significant advantages. First, the excavation workload is relatively small, as it only requires laying a single track, thereby reducing the amount of tunneling needed and lowering both construction costs and operational complexity. Additionally, if the tunnels are laid along the vein itself, this arrangement can be fully leveraged for exploration purposes. For instance, in a small-scale lead-zinc mine with ore bodies ranging from 8 to 12 meters in thickness, a single-track let-off layout along the vein was adopted. During the tunneling process, sampling and analysis of the rock within the vein provided valuable insights into the ore body’s orientation and variations in thickness, offering more precise geological data for subsequent mining operations. Meanwhile, because the tunnels are positioned directly within the vein, the mining process can also recover some additional ore—partially offsetting the tunneling expenses and ultimately boosting the mine’s overall economic efficiency.

However, this layout also presents several issues that require attention. When the ore body’s strike changes, the track lines tend to curve accordingly, significantly impacting transportation efficiency. Curved tracks increase vehicle resistance, reducing operating speed, and simultaneously heighten the risk of derailment, necessitating more careful transport management and equipment maintenance.

2. Double-track crossover

The double-track crossover arrangement involves setting up dual rail lines within the transport roadway and connecting them via a crossover track, enabling vehicles to travel in both directions. Compared to the single-track passing system, this layout significantly enhances throughput capacity, typically reaching 20 to 60万吨 per year—enough to meet the production needs of medium-to-thick orebody mines. For instance, a certain copper mine adopted the double-track crossover arrangement along its vein-level roadways when extracting medium-to-thick ore bodies. The mine’s ore body has a thickness ranging from 15 to 25 meters, with an annual production target of approximately 30万吨. After implementing the double-track crossover setup, motorized locomotives can swiftly traverse the dual rail lines and easily switch directions via the crossover tracks, dramatically boosting the efficiency of ore transportation.

To prevent the loss of ore resources caused by pillar overburden, this copper mine has also implemented an accompanying layout of off-vein roadways. By carefully planning the location and orientation of these off-vein roadways, the placement of mining pillars has become more rational, significantly reducing the pressure exerted by pillars on the ore and thereby boosting the ore recovery rate. Meanwhile, since the dual-track crossover-style roadway layout is relatively straight, motorized vehicles can maintain higher speeds during operation, leading to shorter transportation times and lower energy consumption. According to actual operational data, after adopting this layout design, the average speed of motorized vehicles has increased by approximately 20%, while transportation energy consumption has been reduced by about 15%, effectively lowering the mine’s overall operating costs.

(II) Layout of Lower-Level Double Roadways with Connecting Passages

1. Functional Zone Design

The "lower-level dual roadway system with connecting tunnels" is a relatively complex yet highly efficient layout design, rooted in the concept of functional zoning. It aims to enhance both transportation efficiency and safety. In this arrangement, a driving roadway and a loading roadway are separately laid out within the lower-level surrounding rock. The driving roadway features a straightforward, nearly straight alignment, ensuring safe and efficient vehicle operation. A straight route minimizes bumps and unnecessary turns during transit, thereby reducing vehicle wear-and-tear, lowering the likelihood of mechanical failures, and enabling higher travel speeds—ultimately boosting overall transportation productivity. Meanwhile, the loading roadway is tailored to accommodate variations in the ore body, facilitating seamless loading operations. Given the often irregular shapes and positions of ore bodies, aligning the loading roadway according to these natural contours guarantees that the loading points remain as close as possible to the ore itself. This not only shortens loading time and reduces associated costs but also significantly improves the efficiency of the entire mining process.

In an application at a certain iron mine, the advantages of this layout design were fully demonstrated. After adopting the lower-floor dual-aisle system combined with connecting roadways, the loading efficiency improved by 30%. Analysis of the loading operation process revealed that, thanks to the proximity of the loading aisles to the ore body, haulage trucks could quickly load the mined ore onto transport vehicles, significantly reducing waiting times and empty-trip distances. Moreover, positioning the行车巷 (driving roadway) away from areas where mining-induced stress concentrations were highest not only lowered roadway maintenance costs by 25% but also minimized roadway deformation and damage during mining operations. As mining activities disturbed the surrounding rock mass, substantial ground pressure developed, threatening the stability of the roadways. By strategically placing the行车巷 in a location free from these high-stress zones, the project effectively mitigated such risks, cutting down on both maintenance efforts and expenses while simultaneously extending the service life of the roadway infrastructure.

2. Exploration and Production Integration Optimization

The loading drift is strategically located close to the orebody floor, serving not only as a convenient access point for loading but also playing a crucial role in integrating exploration with mining operations. During the excavation of the loading drift, this provides an ideal opportunity to conduct detailed exploration of the orebody. By collecting, analyzing, and testing rock samples exposed during the excavation process, miners can accurately verify the thickness and grade variations within the orebody. Such data are invaluable for guiding subsequent block design, helping to precisely define block boundaries, select appropriate mining methods, and ensure reliable resource estimation and reserve evaluation.

For moderately thick ore bodies that have been insufficiently explored, this combined exploration-and-mining layout is particularly crucial. In the mining operation of a certain lead-zinc deposit, the preliminary exploration work was not detailed enough, resulting in limited knowledge about the specific characteristics of the ore body. When adopting the "lower-stope double-aisle with connecting drift" layout, continuous exploration efforts conducted during the excavation of the loading drift allowed for a precise understanding of the ore body's thickness, which varied between 12 and 18 meters, while also revealing some fluctuations in grade. Based on these detailed data, subsequent block designs were optimized, with the size and mining sequence of each block adjusted accordingly. This approach not only enhanced ore recovery rates and mining efficiency but also prevented resource wastage and operational challenges that might have arisen from inadequate exploration earlier in the process.

(3) Peripheral Level Roadway with Cross-Drift Layout

1. Building an Efficient Transportation System

The layout of an external drift combined with cross drifts is an efficient transportation system arrangement, commonly used in staged haulage operations at large-scale mines. Specifically, this setup involves constructing a dual-track, two-way driving drift along the footwall outside the orebody, serving as the primary transport artery to ensure high efficiency and uninterrupted flow. The dual-track design enables bidirectional movement, significantly boosting transportation capacity while minimizing the risk of vehicle congestion. Additionally, single-track loading cross drifts are strategically placed every 50 to 80 meters—acting like branching pathways in the transport network, connecting the orebody directly to the main haulage drift. By integrating these cross drifts via single-point turnouts, the system forms a robust "main drift + branch drift" network structure, allowing transport vehicles to seamlessly switch between the main and secondary routes. This flexibility ensures rapid loading and efficient transportation of ore throughout the mining operation.

After adopting this approach at a lead-zinc mine producing 1 million tons annually, transportation efficiency was significantly enhanced. Under this layout, the time required to load a single ore block has been reduced to just 15 minutes—thanks primarily to the well-planned arrangement of cross-cuts and the rapid switching of track switches. Vehicles can swiftly enter the loading cross-cuts, complete the loading process, and then quickly return to the main transport level, dramatically cutting down both loading and waiting times. Moreover, during the excavation of these cross-cuts, the lower boundary of the ore body can be exposed, enabling the dual-purpose use of exploration work and production roadways. By analyzing the rock exposed in the cross-cuts, miners can gain deeper insights into the ore body’s boundaries and geological conditions, providing more precise information for future mining operations. At the same time, this method eliminates the need to repeatedly excavate separate exploration roadways, ultimately saving both costs and valuable time.

2. Coordinated Design of Drainage and Longitudinal Slope

In the arrangement of cross-cuts added to the main drift, the coordinated design of drainage systems and longitudinal slopes is one of the key factors ensuring the smooth operation of the transportation system. The transport routes are designed with a longitudinal gradient of 3‰ to 5‰ for descending heavy vehicles, primarily to meet the requirements of gravity-fed drainage. During mining operations, significant amounts of water accumulate underground; if this water isn't promptly removed, it could compromise transportation safety and disrupt the normal functioning of equipment. By designing the route with a downward slope suitable for heavy vehicles, the accumulated water can naturally flow toward drainage points under gravity, thereby reducing the need for and energy consumption of drainage equipment.

Within the cross巷, a water interception ditch is installed and connected to the main alley's drainage channel, creating a comprehensive drainage network. The interception ditch efficiently collects standing water from the cross alley and directs it into the main alley's drainage system, preventing mud and slurry from contaminating the primary transport route during ore-loading operations. During the ore-handling process—specifically when loading, unloading, and transporting ores—certain amounts of mud and wastewater are generated. If not promptly managed, these effluents could spill into the main transport corridor, compromising vehicle movement and compromising the overall hygiene of the mine’s underground passages. By incorporating the interception ditch and drainage channel, these wastewater streams can be effectively diverted away, ensuring that the main transport route remains clean and dry at all times. This innovative drainage design also fully complies with the "Mine Drainage Design Specifications," meeting stringent requirements for the alleyway’s drainage capacity. As a result, the reliability and safety of the mine’s entire drainage system are significantly enhanced, providing a solid foundation for uninterrupted and efficient mining operations.

(4) Circular Transportation Layout (Upper and Lower Orebody External Level Roadways with Cross-Cut Passages)

1. Ultra-Large Capacity Adaptation Solution

The circular transportation layout—featuring single-track level drifts along the upper and lower orebody boundaries, combined with cross-cut drifts—is an efficient transport solution specifically designed for ultra-high-capacity mines. It is ideal for extracting extremely thick ore bodies with annual production capacities exceeding 1.5 million tons. In this setup, single-track行车 drifts are established in the surrounding rock strata above and below the orebody, interconnected via cross-cut drifts to form a continuous loop. This circular structure enables transport vehicles to circulate seamlessly between the upper and lower levels, allowing multiple mining blocks to be serviced simultaneously—and significantly boosting overall transportation capacity.

A certain nickel mine adopted this layout configuration when mining extremely thick ore bodies, achieving remarkable results. The mine has set an annual production target of 3 million tons, and through the implementation of a circular transportation system, it has enabled multiple ore blocks to be simultaneously extracted, fully meeting the designed transportation capacity. In actual operations, the spacing between crosscuts was carefully engineered to match the length of a single train—approximately 60 meters—ensuring efficient loading at the decline shafts. When trains enter the crosscut lateral tunnels for loading, the optimized crosscut spacing allows them to dock smoothly and load quickly, significantly reducing both loading time and vehicle waiting periods, thereby enhancing the overall efficiency of the transportation system.

2. Ground Pressure Management and Roadway Protection

When adopting a circular transportation layout, ground pressure management and roadway protection are critical components. Since mining activities can induce stress changes and rock mass movement, this may lead to roadway deformation or even failure, compromising transportation safety. Therefore, it is necessary to calculate the minimum distance between the roadway and the orebody boundary based on the angle of rock mass movement, ensuring that the roadway remains outside the predicted movement zone after the next stage of mining operations.

According to the formula for calculating the minimum distance between a roadway and the ore body boundary based on the rock mass movement angle—where represents the minimum distance, is the stope height, is the dip angle of the hanging wall, and is the ore body dip angle—in practical applications at a certain mine, the stope height was set at 50 meters, the hanging wall movement angle at 60°, and the ore body dip angle at 75°. After calculation, a safety margin of 15 meters was deliberately left during actual layout to ensure safety. This approach effectively prevents the roadway from being affected by mining activities, thereby maintaining both the stability of the roadway and the safety of transportation, ultimately providing a solid foundation for the mine’s long-term, stable production.

III. Layout Optimization Strategies for Special Operating Conditions

(1) Rock Layer Avoidance Under Complex Geological Conditions

1. Identification and Avoidance of Unfavorable Rock Formations

In the process of mine excavation, avoiding rock strata under complex geological conditions is a critical step to ensure the safe and stable operation of stage transportation roadways. Among these challenges, accurately identifying and bypassing unfavorable rock formations is the top priority. Advanced drilling technology effectively enables the detection of fault fracture zones, karst-developed areas, and other hazardous rock layers ahead of time. By conducting pre-excavation drilling, miners can thoroughly assess the geological conditions ahead, gathering vital information on rock structure, properties, and groundwater presence. Once such unfavorable formations are identified, engineers can implement an off-vein bypass strategy, routing the roadway through relatively stable rock sections instead.

During the mining process at a certain mine, when the tunnel excavation reached a specific area, advanced drilling revealed the presence of a shale layer ahead. Shale is known for its tendency to soften upon contact with water, posing a significant threat to the stability of the tunnel. After careful deliberation and analysis by technical experts, it was decided to reroute the tunnel into the sandstone located 5 meters beneath the roof. Sandstone exhibits superior stability and strength, effectively supporting the surrounding ground pressure. This strategic adjustment successfully prevented tunnel deformation caused by the softening of mudstone in wet conditions. Long-term monitoring has shown that the maintenance cycle for this tunnel has now been extended to over 5 years, significantly reducing both maintenance costs and safety risks.

2. Strengthening Support for Soft Rock Roadways

For soft-rock environments such as mudstone and coal-bearing strata, simply bypassing the area is not enough—strengthening and supporting the roadway is also essential. A highly effective approach is the combined support system of "anchor bolts with mesh and cables plus U-shaped steel supports." Anchor bolts securely connect the surrounding rock of the roadway to stable bedrock, providing robust anchoring force. Meanwhile, anchor cables further enhance this anchoring effect, significantly boosting the load-bearing capacity of the surrounding rock. Reinforcing steel mesh helps prevent loose fragments from falling off the rock surface, thereby improving the overall integrity of the surrounding rock mass. Finally, the U-shaped steel supports offer powerful structural support, effectively resisting the deformation pressures exerted by the soft rock.

In the soft-rock roadway of a certain coal mine, a combined support system of "anchor-net-cable + U-shaped steel supports" was implemented, complemented by an inverted arch structure on the floor. This inverted arch design helps distribute the pressure from the floor evenly to the sides, significantly reducing upward deformation of the floor. Thanks to this advanced support approach, the roadway's convergence deformation has been effectively controlled to less than 50 mm per year, ensuring long-term stability and reliability for its continued service. During actual operation, the roadway has withstood multiple mining-induced stresses while maintaining excellent condition, providing a dependable passage for coal transportation.

(II) Adaptation of Roadways for Trackless Equipment Mining

1. Optimized Design of the Ore Extraction System

With the widespread adoption of trackless equipment in mining operations, the layout of stage transportation roadways must align with the operational characteristics of these vehicles. Among these considerations, optimizing the ore-discharging system is crucial. By adopting a layout featuring "ore-discharging roadways combined with ore-discharging access routes," we can significantly enhance the efficiency of trackless equipment operations. When designing the width of the ore-discharging access routes, it’s essential to account for both the operational safety of the loaders and the necessary maneuvering space—typically, the route should be 1.5 meters wider than the loader itself. This ensures that the loader can smoothly navigate turns and travel along the route without colliding with the roadway walls. Additionally, a safety clearance of 0.5 meters should be预留 (reserved) at the top to prevent equipment from being obstructed by overlying rock during operation.

Turning radius is also an important design parameter, typically no smaller than the equipment’s minimum turning radius—usually ranging from 8 to 10 meters. A properly designed turning radius ensures the stability and safety of the scraper during turns, while also reducing equipment wear and minimizing the likelihood of mechanical failures. In a certain gold mine where scraper trucks are used for transportation, the length of the ore extraction routes was strictly controlled, maintained between 30 and 50 meters. This specific route length helps prevent the scrapers from undertaking long-distance uphill climbs, which would otherwise lead to increased energy consumption, thereby lowering operational efficiency. Thanks to these optimized design measures, the mine has achieved a significant improvement in the operational efficiency of its trackless equipment, while also managing to reduce overall ore transportation costs.

2. Ventilation and Dust Removal in Coordination

Trackless equipment generates significant exhaust gases and dust during operation, severely impacting the underground working environment and worker health. Therefore, when arranging roadways, it's essential to carefully consider the synergistic effects of ventilation and dust control. To ensure efficient removal of diesel locomotive exhaust, the roadway cross-section needs to be expanded to 12–15㎡. A larger cross-section not only increases ventilation volume but also enhances air flow velocity, enabling more effective dilution and expulsion of exhaust gases.

By combining local ventilation fans with dry dust collectors, it is possible to further reduce dust concentrations. The local ventilation fans deliver fresh air directly to the work area, effectively dispersing and diluting airborne dust. Meanwhile, the dry dust collectors filter and capture dust particles from the air, ensuring that dust levels remain below 2 mg/m³—thus meeting occupational health standards. In a trackless equipment roadway at a certain iron mine, highly efficient local ventilation fans and dry dust collectors have been installed, and the ventilation system along with the dust collection equipment undergo regular maintenance and inspections. These measures have significantly improved the underground working environment, safeguarding the health of workers while also extending the service life and enhancing the operational efficiency of the equipment.

IV. Project Cases and Benefit Analysis

(1) Typical Cases of Open-Pit Mining

During the mining process, a certain quartzite mine utilized off-vein stage transport roadways, fully leveraging the advantages of this layout. The orebody beneath the mine featured a fractured zone; to ensure the stability of the roadways and the safety of transportation, technicians conducted thorough geological surveys and analyses before deciding to position the stage transport roadways entirely outside the vein. Simultaneously, they integrated cutting and floor-cutting roadways along with inclined shafts, creating a comprehensive ventilation and transportation system. In terms of roadway support, spray-anchor reinforcement technology was employed, effectively enhancing the stability of the surrounding rock by combining the supportive action of rock bolts with sprayed concrete.

During the actual service period, no roof collapse incidents occurred in this roadway, providing a strong guarantee for the mine's safe production. The mining room extraction efficiency reached 80 tons per shift, demonstrating that this layout effectively enhances mining productivity and meets the mine's operational demands. Compared to the traditional intravein vein layout, this design reduces ore pillar losses by 15%. By optimizing the roadway arrangement, it prevents excessive pressure from ore pillars on the mined ore, thereby boosting ore recovery rates, minimizing resource waste, and delivering significant economic benefits to the mine.

(II) Practical Application of Caving Method in Mine Layout

In a certain iron mine employing the caving method for extraction, the layout of the stage transportation drifts was carefully designed. Considering that caving mining can cause rock mass movement and changes in ground pressure, to prevent the drifts from being affected, the stage transportation drifts were positioned 20 meters outside the hanging-wall rock-movement zone. The design features a dual-hangwall drift system connected by cross-cuts, with the loading drift also serving as an exploration drift. During the excavation of the loading drift, technicians took full advantage of this opportunity to conduct detailed exploration of the orebody. By sampling, analyzing, and testing the exposed rocks, they were able to identify in advance any variations in the orebody boundaries.

This initiative has enabled the mine to reduce the rate of waste rock contamination during mining by 8%. By accurately identifying the ore body boundaries in advance, the mining process can more precisely control the extraction area, effectively preventing the mixing of large amounts of waste rock and thereby improving the quality of the ore. Meanwhile, the straight design of the haulage tunnels allows motorized cars to maintain higher speeds during operation. Actual tests have shown that the speed of motorized cars has increased by 20%, significantly boosting transportation efficiency. As a result of this improved efficiency, annual transportation costs have been reduced by 12%. Through rational tunnel layout and an optimized transportation system, this iron mine has not only lowered its transportation costs but also enhanced both production efficiency and overall economic benefits.