01. Regulatory Requirements for the Proper Placement of Emergency Exits

The basic configuration principles for independent safety exits

Each mine must be equipped with at least two independent safety exits, and the distance between these exits must not be less than 30 meters. This is a fundamental principle in mine safety construction. For instance, a gold mine in Shandong strictly adhered to this standard during its initial construction phase, establishing two safety exits located at different orientations within the mining area. During a minor roof collapse incident, one of the exits experienced localized blockage near its vicinity; however, miners swiftly evacuated through the other safety exit in an orderly manner, successfully preventing any casualties. For large-scale mines where the length of a single wing exceeds 1,000 meters, adding an additional safety exit at the lower section of the end boundary is a critical measure. Take, for example, a major coal mine in Shanxi Province, whose minefield extends over 1,500 meters along a single wing. By installing an extra safety exit at the lower end boundary, the mine has not only optimized underground evacuation routes but also significantly reduced personnel evacuation time during subsequent gas leakage emergency drills, thereby enhancing the mine's overall capability to handle unexpected incidents. This configuration standard strictly follows the "Safety Regulations for Metal and Non-Metal Underground Mines," ensuring risk diversification through multi-exit layouts and providing robust support for safe mine operations.

Key Considerations for the Functional Layout of Safety Exits

The layout of safety exits must be closely integrated with the underground development system to create an efficient emergency evacuation network. In a lead-zinc mine in Sichuan, safety exits are strategically connected to major transportation drifts and positioned near ventilation shafts, ensuring that personnel can evacuate swiftly while maintaining adequate ventilation during emergencies. The placement of exits should avoid areas where stress concentrations occur after mining activities, as these regions may experience roadway deformation, potentially blocking access routes. For instance, in an iron mine in Inner Mongolia, localized stress concentrations caused roadway deformations, reducing the accessibility of safety exits near those areas. Subsequently, by optimizing exit locations away from stress concentration zones and reinforcing roadway support structures, the mine successfully maintained unobstructed access to safety exits. Additionally, the surface-level terminus of each safety exit must feature prominent signage, such as reflective indicator boards, and should be conveniently linked to critical safety facilities within the industrial site, including first-aid stations and fire escape routes. A coal mine in Henan has implemented this approach by installing eye-catching signage and lighting systems at the surface end of its safety exits, along with dedicated emergency pathways that connect seamlessly to nearby first-aid stations, significantly enhancing the efficiency of emergency response operations.

02. Systematic Considerations for Ground Environment Adaptation

Coordinated Layout of Industrial Sites and Wellheads

The site selection for the shaft entrance must reserve sufficient industrial land to accommodate the layout of surface facilities such as hoisting equipment, ventilation rooms, and substations, while also considering material storage areas, transportation route planning, and future expansion space. Site planning should adhere to functional zoning principles, separating high-risk areas (e.g., explosives storage) from densely populated zones. By leveraging natural terrain, the design aims to streamline logistics flows and minimize cross-interference among ground-level operations. The vertical design of the industrial site must align with the elevation of the shaft entrance to ensure an efficient and reliable drainage system, preventing waterlogging that could disrupt normal mine operations. For instance, at a certain coal mine in Huainan, the industrial site is divided into production, auxiliary, and residential zones based on topography. Within the production zone, the hoisting room is strategically located adjacent to the shaft entrance, shortening the material-handling path. In the auxiliary zone, ventilation rooms and substations are arranged optimally, with carefully planned routes that reduce energy losses. The site employs a flat-slope vertical design, utilizing natural gradients to construct open drainage channels that effectively manage rainwater runoff and mine water discharge, ensuring both dry conditions and operational safety across the entire industrial area. This layout not only enhances production efficiency but also leaves ample room for future technological upgrades and capacity expansions, effectively reducing expansion costs and safety risks associated with site limitations.

Geological Disaster and Flood Control Safety Management

The wellhead must be located in a geologically stable area, away from flood-prone zones, landslide areas, and regions susceptible to debris flows. The elevation of the wellhead should exceed the local historical highest flood level by more than 1 meter; for special areas such as valley-type mines, this requirement should be increased to 2–3 meters, accompanied by the construction of additional engineering facilities like diversion ditches and flood control embankments. In karst-developed regions, it is essential to conduct thorough geological surveys to identify surface collapse risks clearly. Appropriate measures, such as pile foundation reinforcement and concrete retaining walls, should be implemented to enhance the stability of the wellhead foundation, ensuring safe production even under extreme weather conditions. For instance, a lead-zinc mine in Guangxi is situated in a karst landform area with underground caves near the wellhead. During the construction phase, high-precision ground-penetrating radar surveys combined with borehole explorations were conducted to accurately map the distribution of these caves. Reinforced concrete cast-in-place piles were then used to strengthen the wellhead foundation, with pile lengths extending deep into stable bedrock. Simultaneously, grouting techniques were applied to seal and stabilize the identified cave systems. Additionally, diversion ditches and retaining walls were strategically installed around the wellhead area. The diversion ditches were designed according to the terrain to channel upstream floodwaters safely away from the site, while the retaining walls effectively mitigated the risks posed by mountain landslides and debris flows. In recent years, during periods of intense rainfall, the mine's wellhead and industrial facilities have successfully withstood severe weather challenges without any safety incidents, thereby maintaining uninterrupted production operations at the mine.

External Connectivity and Land Resource Protection

The wellhead location should prioritize areas directly connected to external railway and highway networks, minimizing material transfer processes and reducing transportation costs. At the same time, strict adherence to the principle of land conservation is essential, achieved through optimized site layouts and the adoption of three-dimensional facility arrangements to minimize the occupation of farmland and ecologically sensitive zones. For mining areas involving basic farmland, a comprehensive land reclamation plan must be developed to ensure that mining activities have minimal impact on surrounding agricultural production, thereby promoting coordinated development between resource exploitation and environmental protection. For instance, a coal mine in Shanxi Province collaborated with the local railway authorities to construct a dedicated railway branch line near the wellhead, enabling direct loading and transportation of coal for shipment. The industrial site features a multi-level architectural design, with facilities such as substations and maintenance workshops arranged vertically to maximize space efficiency and reduce overall land use. In areas where farmland was temporarily occupied during mining operations, a detailed land reclamation plan has been implemented. During the extraction process, topsoil layers are carefully separated and stored separately. Once mining activities conclude, these topsoils will be used for land leveling, soil improvement, and vegetation restoration, ensuring that reclaimed land can be fully restored to its original or even enhanced state for future agricultural use. Moreover, the mine actively collaborates with neighboring rural communities to launch ecological agriculture projects, leveraging the reclaimed land within the mining area to cultivate specialty crops. This approach not only fosters a positive synergy between resource development and agricultural growth but also contributes to sustainable regional development.

03. Engineering Feasibility Analysis of Subsurface Geological Conditions

The core control indicator for formation stability

The stability of the strata in the primary development roadway directly impacts its long-term safety and operational efficiency, making the core control indicators critical for guiding roadway site selection and design. In an underground copper mine in Yunnan, preliminary geological exploration involved drilling to obtain rock core samples and employing geophysical methods such as ground-penetrating radar to map subsurface structures, ultimately establishing a detailed stratigraphic profile model. The results revealed that certain areas within the mining zone contain fractured zones, with an RQD (Rock Quality Designation) as low as 30% and a uniaxial compressive strength of only 15 MPa. Based on comprehensive assessments, the primary development roadway was strategically positioned within stable strata characterized by an RQD of at least 70% and a uniaxial compressive strength exceeding 50 MPa. For localized fractured zones that could not be avoided, a combined support system was implemented, incorporating prestressed anchor cables and steel arch supports. Specifically, the anchor cables were installed at 8-meter lengths with a spacing of 1.5 meters, while the steel arch supports utilized No. 18 I-beams spaced at intervals of 0.8 meters. These measures effectively enhanced the stability of the surrounding rock mass, ensuring safe and reliable operation of the roadway throughout its service life and mitigating the risks of roadway collapse or production disruptions caused by unstable strata conditions.

Avoidance and Response Strategies for Hydrogeological Conditions

The impact of hydrogeological conditions on roadway safety cannot be overlooked. Developing reasonable avoidance and response strategies is a critical component in ensuring the safety of underground operations. In a lead-zinc mine located in Hunan Province, detailed hydrogeological surveys were conducted prior to roadway alignment selection. By monitoring groundwater level fluctuations and analyzing groundwater flow directions, it was determined that multiple water-conducting faults and fractured zones exist within the mining area. To prevent direct contact between roadways and aquifers, the roadways were strategically positioned in relatively impermeable strata away from these water-conducting structures. Additionally, drainage channels were incorporated into the roadway design, with drainage chambers installed every 50 meters and equipped with multi-stage pumping stations. The total drainage capacity of these pumps exceeds twice the normal inflow rate, ensuring effective handling of sudden water surges. During roadway construction, waterproof concrete was used for lining the tunnel walls, achieving an impermeability rating of P8. Local fractures were also treated through grouting techniques, utilizing a cement-sodium silicate dual-component slurry as the grouting material. These comprehensive measures have established a robust roadway waterproofing system, effectively preventing groundwater infiltration that could lead to surrounding rock softening and structural instability. As a result, the safe working environment underground has been significantly enhanced, substantially reducing the likelihood of water-related accidents.

04. Special Technical Requirements for Ventilation Systems and Seismic Design

Optimization of Airflow Organization in Ventilation Shafts and Roadways

The intake shaft should be located on the upwind side of the area's prevailing wind direction throughout the year. This positioning ensures that fresh air entering the mine is not contaminated by surface pollution sources. For instance, in some mining areas surrounded by waste rock piles or ore-processing plants, if the intake shaft were positioned downwind, dust and exhaust gases emitted from these sources could easily be drawn into the shaft, thereby polluting the underground working environment and posing serious health risks to miners. On the other hand, the return shaft should be placed on the downwind side, allowing natural wind currents to enhance the dispersion of stale air and facilitate the rapid removal of polluted air from the mine, minimizing its residence time and reducing the extent of contamination underground. For radioactive mines, the spacing between the intake and return shafts must strictly exceed 300 meters. This requirement stems from the fact that radioactive mines generate radioactive dust during the mining process. By maintaining a greater distance between the two shafts, the airflow path is significantly lengthened, effectively reducing the risk of cross-contamination between the intake and return shafts. Take, for example, a specific radioactive mine where precise ventilation system design and stringent spacing controls have been implemented. These measures have successfully lowered the concentration of radioactive dust underground, ensuring enhanced occupational health and safety for miners.

During the ventilation system design process, conducting three-dimensional flow field simulations in conjunction with orebody trends and roadway layouts is a critical step. By establishing a 3D model, it becomes possible to precisely analyze wind velocity and pressure distribution under various operational conditions. For instance, using specialized ventilation simulation software, input geological data of the mine, roadway layout diagrams, and fan parameters to simulate airflow patterns for different seasons and mining stages. Based on these simulation results, optimize wind speed and pressure parameters to ensure that ventilation efficiency meets the required standards at each working face. In an optimization project for a certain metal mine's ventilation system, 3D flow field simulations revealed insufficient airflow in several working areas. Following adjustments to fan positions and blade angles, along with optimized ventilation cross-sections in roadways, the ventilation efficiency at each working face improved by more than 20%, significantly enhancing the underground working environment.

Structural Reinforcement Measures for Areas Prone to Frequent Earthquakes

In regions experiencing seismic intensity of 6 or higher, surface buildings and structures in mines must undergo seismic design. A common seismic protection measure is the adoption of a frame structure, which offers excellent overall integrity and ductility. Under earthquake loads, such structures can dissipate seismic energy through controlled deformation, significantly reducing the extent of building damage. Additionally, base isolation technology is an effective method for enhancing seismic performance. By installing isolation bearings—such as rubber isolation bearings or sliding bearings—between the foundation of a building and its superstructure, this approach effectively isolates seismic energy from being transmitted upward, thereby minimizing the building's response during an earthquake. For instance, in a mine located in a seismically active area of Yunnan Province, the office building was designed with both a frame structure and base isolation technology. During a magnitude 5.5 earthquake, the building sustained only minor cracks, while the main structural framework remained intact, ensuring the safety of personnel and maintaining normal operation of office facilities.

Anti-seismic buffer structures must be installed at the entrances of shafts and major roadways. Flexible joints can absorb seismic energy through their inherent deformation, thereby reducing the impact of earthquake waves on shafts and roadways. Energy-dissipating supports, on the other hand, utilize their energy-absorbing properties to dissipate seismic energy during an earthquake by means of material yielding and deformation, thus minimizing the structural response to seismic forces. Equipment foundations must undergo anti-seismic verification calculations. Based on the equipment type, weight, and the magnitude of seismic forces, the foundation's load-bearing capacity under seismic conditions should be evaluated to ensure it meets all required standards. Additionally, vibration-reducing devices such as spring dampers or rubber shock pads should be installed for each piece of equipment to minimize vibrations and displacements during an earthquake, ensuring that critical systems like hoisting and ventilation equipment can continue operating smoothly even under seismic conditions. For instance, in a mine located in Sichuan Province, the foundation of a hoisting system was reinforced against earthquakes by increasing its embedment depth and reinforcement density, along with the installation of spring dampers. Following a 6.0-magnitude earthquake, the hoisting equipment experienced only minor swaying. After a brief inspection, it resumed normal operation promptly, effectively maintaining the mine's production continuity.

Additionally, developing an earthquake emergency response plan is a crucial measure for mines to effectively address seismic disasters. The emergency plan should outline key components such as personnel evacuation routes following an earthquake, the organizational structure for rescue operations, and the stockpiling of essential emergency supplies. Moreover, regular seismic performance assessments and emergency drills should be conducted. These assessments help identify potential vulnerabilities in buildings, structures, and equipment related to earthquake resistance, enabling targeted measures to be implemented promptly for remediation. Meanwhile, emergency drills play a vital role in enhancing the mine employees' emergency response capabilities and their ability to work collaboratively, ensuring that, in the event of an earthquake, personnel can evacuate and carry out rescue operations swiftly and systematically. For instance, a mine in Shaanxi Province conducts annual earthquake emergency drills, continuously refining its emergency response plan through these exercises and significantly boosting employees' awareness and preparedness. During a real earthquake incident, the mine's staff successfully followed the emergency plan to evacuate safely and initiate self-rescue efforts, thereby preventing casualties and minimizing substantial property damage.

05. An Engineering Practice Path for Multi-Factor Collaborative Optimization

A lifecycle-based methodology for scheme comparison

In the process of determining tunnel locations, establishing a multi-objective decision-making model is crucial for achieving scientific site selection. Taking a coal mine in Anhui Province as an example, during the development of a new mining area, multiple tunnel location options were considered. By constructing a multi-objective decision-making model that incorporates safety, economic factors, environmental considerations, and technical aspects, the Analytic Hierarchy Process (AHP) was employed to determine the weights of each factor. Specifically, given the relatively high methane content in the mine, the weight assigned to ventilation safety was set at 0.3. Economically, due to the remote location of the mine from major markets, transportation costs accounted for a significant portion; thus, the weight for transportation expenses was set at 0.25. From an environmental perspective, considering the presence of farmland and rivers surrounding the mining area, the weight for ecological protection was established at 0.2. On the technical side, based on the complexity of geological conditions, the weight for surrounding rock stability was set at 0.25. To evaluate the stability of the surrounding rock under different scenarios, numerical simulation software FLAC³D was utilized to analyze the results. Additionally, ANSYS was applied to simulate ventilation performance. Furthermore, the Life Cycle Cost (LCC) theory was adopted to calculate the capital investment and ongoing operation and maintenance costs associated with each option. Through comprehensive evaluation, the optimal solution was selected—this option not only minimized economic costs but also ensured favorable ventilation performance while meeting the required standards for surrounding rock stability. Subsequent mining operations have demonstrated that this chosen approach effectively reduced the incidence of safety incidents, lowered operational expenses, and ultimately supported the sustainable development of the mine.

Intelligent Exploration and Dynamic Adjustment Mechanism

Intelligent exploration technology plays a crucial role in the early stages of tunnel site selection. Taking a gold mine in Shandong Province as an example, advanced 3D geological modeling software DIMINE was employed to integrate geological exploration data and construct a high-precision underground geological model. Simultaneously, UAV-based remote sensing was utilized to acquire surface topographic data, enabling precise alignment between surface and subsurface information. During the modeling process, comparative analysis of geological data from different periods revealed localized trends of geological structural changes within the mining area. Based on these findings, the tunnel site selection plan was promptly adjusted to mitigate potential geological risks. In the tunnel construction phase, stress sensors and displacement monitors were embedded into the surrounding rock mass to collect real-time data continuously. When sudden increases in stress or displacements exceeding preset warning thresholds were detected in specific sections of the tunnel, the dynamic feedback model was immediately activated. This triggered adaptive adjustments to the original design, including modifications to support parameters and optimization of excavation techniques. These intelligent approaches not only enhanced the safety of tunnel construction but also significantly reduced subsequent maintenance costs, ensuring efficient and sustainable mining operations.

Compliance Review and Standardization Development

Compliance review is a critical phase in mine construction and must strictly adhere to relevant laws and regulations. During the roadway design stage of a lead-zinc mine in Guangdong, a third-party safety evaluation agency was engaged to assess key indicators such as the spacing of safety exits, flood protection elevations, and seismic design standards, based on regulatory documents like the "Mine Safety Regulations" and the "Safety Standardization Guidelines for Metal and Non-Metallic Mines." For instance, given that the mine is located in an area with a seismic intensity of 7 degrees, the surface buildings and structures underwent seismic-resistant design according to regulatory requirements, incorporating frame structures and base isolation technology. Additionally, a standardized site-selection process and technical documentation system were established, enabling the company to formalize previously successful site-selection practices into internal corporate standards. In subsequent mine expansion projects, modular design approaches were adopted to swiftly determine roadway locations, significantly enhancing engineering efficiency. This systematic and scientific approach not only streamlined project implementation but also effectively minimized safety risks and economic losses associated with non-compliant operations.