In 1956, in accordance with the "Twelve-Year Plan for Scientific and Technological Development" formulated by the former State Science and Technology Commission, preparatory work was conducted for the establishment of the Nonferrous Metal Mining Research Institute, and the institute was founded. In 1962, it was renamed Changsha Institute of Mining Research. It was formerly affiliated with the Ministry of Metallurgical Industry and the China National Nonferrous Metals Industry Corporation, and is now an important science and technology-based enterprise directly managed by China Minmetals Corporation. Over the past 70 years, Changsha Institute of Mining Research has been devoted to integrated comprehensive services covering design and consulting, technology development, inspection, testing and certification as well as engineering construction and operation and maintenance, for the entire process and full life cycle of the development and utilization of mineral resources. It was once ranked 16th in comprehensive strength among more than 800 research institutes administered by former national ministries and commissions, and it is widely recognized as "China's No.1 Institute in Metal Mining". In line with the national strategy for ensuring the supply and security of mineral resources, 1 088 major scientific and technological achievements have been made by Changsha Institute of Mining Research in fields such as mining technology, mine safety, mine backfilling, water prevention and control, digital and intelligent mines, intelligent equipment, testing and inspection, and mineral processing technology. Among them, 890 scientific and technological achievements have been awarded, including 63 National Science and Technology Awards (2 Special Prizes and 4 First Prizes of the National Science and Technology Progress Award). In addition, 1 217 patents have been granted, including 434 invention patents, and 55 national and industry standards have been compiled with the institute as the lead or participating unit. And the related scientific and technological achievements have been promoted and applied to more than 3 000 enterprises at home and abroad. The 70-year scientific and technological development history of Changsha Institute of Mining Research was systematically reviewed, its major scientific and technological achievements and industry contributions were summarized, the practical challenges facing the development of the industry were analyzed, and an outlook on future directions of scientific and technological innovation in the mining field was provided. A reference is thereby provided for the high-quality development and scientific and technological self-reliance and self-strengthening of China's mining industry.

As shallow metal mineral resources become increasingly depleted, advancing into the deep subsurface has become an inevitable strategic choice for safeguarding national resource security. However, the complex geomechanical environment characterized by "three highs and one disturbance" in deep mining poses severe challenges to conventional stoping methods in terms of safety, cost control, and operational efficiency. By reviewing typical engineering practices of deep mines at home and abroad and recent research achievements, the development status, key engineering technical difficulties, and main technological paths of deep metal mining were systematically summarized. The applicability and limitations of deep mining methods under different ore body occurrence conditions was analyzed, and it was pointed out that "large-scale mining, intelligent equipment, and continuous operation" constitute the core direction of deep mining technological transformation. For three typical types of ore body occurrence conditions, namely thick and stable ore bodies, fractured ore bodies, and thin veins in deep mining, technical systems were respectively proposed with high-stress coupled rock fragmentation and modular continuous stoping, environmental reconstruction and stress-relief mining, as well as precise blasting and waste-free efficient stoping as the core. Meanwhile, the application potential of non-explosive mechanized continuous mining technology in reducing disturbance and enhancing inherent safety was also analyzed. This study aims to provide a theoretical basis and technical pathways for the transformation of deep metal mining in China from traditional modes to intelligent and continuous technology systems, thereby contributing to the formation of new quality productive forces in metal mineral resource development.

Deep orebody mining generally faces a complex occurrence environment characterized by high in-situ stress, high ground temperature, high osmotic pressure, and strong mining disturbance. Conventional backfill mining technologies and equipment struggle to meet the demands of safe and efficient mining. Under large-scale deep mining conditions, deep shafe backfill faces problems such as high hydration heat release of cementitious materials, slow backfill formation, insufficient backfill system capacity, and high-potential-energy slurry transport that easily induces partially filled pipe flow, water hammer, and pipe bursting risks. These issues have become key bottlenecks restricting the safe and efficient mining of deep mines. Focusing on the engineering requirements for large-scale, safe, and efficient backfill in deep metal mines, three key issues were proposed: the rapid and sustained low-heat solidification mechanism of ultrafine tailings backfill slurry, the pressure regulation and high-efficiency energy utilization mechanism of full-pipe transport in deep shafts, and the stability control and formation mechanism of high backfill under deep high in-situ stress. Four key technologies were systematically summarized: performance regulation of low-heat, early-strength, and high-strength backfill cementitious materials; large-scale continuous and steady-state thickening of ultrafine tailings; pressure-reducing power generation and full-pipe transport safety assurance for deep mine backfill slurry; and formation and quality assurance of high backfill under deep high in-situ stress. The research and development directions for new materials, technologies, and equipment for green and efficient backfill in metal mines at depths of over 1 000 m and with capacities of tens of millions of tons were clarified, and a large-scale, safe, and efficient backfill technology system for deep mining was constructed. This aims to comprehensively enhance China's capacity for green and efficient development of deep strategic mineral resources and provide a theoretical basis and technical support for the large-scale development of deep mineral resources.

As metal mining extends to depths greater than 1 000 m, the water hazard occurrence environment and disaster-causing process exhibit characteristics such as high confined pressure coexisting with weak water yield, high stress-high water pressure coupling, diverse water sources, concealed water-conducting channels, and significant time-dependent disaster evolution. The traditional prevention and control mode, which is dominated by static hydrogeological condition analysis and passive drainage, can no longer meet the requirements of safe deep mining. Based on the long-term research and engineering practice achievements of Changsha Institute of Mining Research Co., Ltd in mine water hazard prevention and control, this paper systematically summarized four aspects: water hazard characteristics, disaster-causing mechanisms, prevention and control technologies, and coordinated groundwater safety management. Firstly, the types and basic characteristics of water hazards in deep metal mines were sorted out from the dimensions of water sources, water-conducting channels, and disaster-causing modes. Secondly, the mechanisms of initiation, triggering, and evolution of deep water hazards were elucidated from three levels: geological structure-controlled water, rock mass damage-seepage coupling under high stress-high water pressure, and thermal-hydraulic-mechanical-chemical multi-field coupling. Finally, key technologies such as fine hydrogeological exploration, water inrush risk assessment, curtain grouting, sealing of strong dynamic water channels, controlled dewatering, flooded shaft treatment, and multi-source information monitoring and early warning were summarized. A closed-loop prevention and control system of "fine exploration-risk assessment-engineering treatment-monitoring and early warning" was constructed. The research can provide a theoretical basis and engineering reference for the collaborative development of deep metal mine water hazard prevention and control from single disaster treatment to safe mining, groundwater resource utilization, and ecological environment protection.

With the increasing complexity of orebody occurrence conditions and the continuous improvement of resource recovery requirements, complex fractured orebodies have become important targets for safe, efficient, and low-dilution-loss mining in metal and non-metal mines. The backfill mining method provides an important technical approach for the mining of such orebodies by controlling stope exposure, reconstructing the surrounding rock-pillar-backfill bearing relationship, and regulating the mining-backfill cycle. Based on a review of research and engineering applications of backfill mining at home and abroad, starting from the basic conditions and dominant control mechanisms of orebodies, the backfill mining methods for complex fractured orebodies were categorized into the small-exposure continuous mining category, structural unit delayed backfill category, and strong-control combined support backfill category. Furthermore, combined with typical cases, their applicable conditions, control mechanisms, and engineering effects were compared. The research results show that the small-exposure continuous mining category is suitable for the fine mining of thin and narrow orebodies, and orebodies with complex boundaries; the structural unit delayed backfill category can balance the production capacity and stope bearing conversion of medium-thick to massive orebodies; the strong-control combined support backfill category can improve the stability control capability for weak roofs, large spans, and local fractured zones. At the present stage, it is still necessary to focus on solving issues such as the matching of engineering geological conditions and method parameters, the sequential connection of mining and backfilling, the process control of dilution and loss, the composite bearing mechanism, and technical economy. In the future, geological zoning, function-oriented backfill design, collaborative organization of mining-support-backfill-transport, and dynamic optimization driven by monitoring feedback should be strengthened.

As the core technology of green mining in metal mines, unclassified tailings paste backfill technology plays an irreplaceable role in the coordinated development of mineral resource exploitation and ecological environment protection. A systematic review of research literature on unclassified tailings paste backfill technology at home and abroad was conducted, and the research progress was summarized from multiple dimensions such as technological development history, paste thickening and preparation, pipeline transportation, and engineering application cases. Research shows that the research on backfill technology at home and abroad has gone through four evolutionary stages: dry backfill, hydraulic backfill, cemented backfill, and paste backfill. Currently, paste backfill technology is developing rapidly in the direction of "high concentration, large flow rate, intelligentization, and green development". The core achievements of the complete technology system for paste backfill were systematically discussed, including the low-energy flocculation of tailings slurry synergistic with high-concentration stable sand discharge technology, the high-quality preparation of multi-component material paste synergistic with reliable transportation technology, the pressure-regulated paste transportation and backfill safety control technology in ultra-deep shafts, as well as the independent research and development progress of key backfill equipment such as paste storage thickeners, high-speed flexible mixers, and cone-valve industrial backfill pumps. Through engineering cases such as the Shizhuyuan polymetallic mine, the successful application effects of the technology and equipment in different mines were demonstrated. Combined with current technological research and future development trends, the development path of paste backfill technology towards deep underground and green development was prospected, aiming to provide technical reference and decision-making support for the green and low-carbon transition of the mining industry in China.

The treatment of goafs is crucial for residual ore recovery. Selecting a backfill with reasonable strength to treat the goaf, so as to prevent the premature instability of pillars caused by stress concentration, is a key prerequisite for ensuring the safe and economic recovery of subsequent pillars. To address the problems of early left-over goafs and residual pillars in a certain fluorite mine, the short-hole shrinkage subsequent filling mining method suitable for medium-thick ore bodies was adopted to recover the pillars. Furthermore, the strength range of the backfill was preliminarily determined to be 1.06-2.08 MPa through theoretical empirical formulas, and then the final backfill strength was determined in combination with numerical simulation. The results show that when the backfill strength is 2.0 MPa, it can effectively alleviate the stress concentration phenomenon at the top and bottom of the backfill, reduce the pressure relief range of the side walls on both sides, ensure that the displacement and deformation of the backfill on the side walls of the pillar stope do not exceed 50 mm, and simultaneously avoid the large-area plastic zone penetration between the backfill and the pillar. After the goafs were treated with backfill with a strength of 2.0 MPa at the site, the cumulative volume of filled goafs is approximately 337 339 m³. A total of 83 000 t of residual roof and sill pillar ores are recovered, and the total profit reaches 36.88 million yuan. While ensuring safe underground recovery, the economic benefits of the mine are significantly improved.

To address the time-varying problem of rheological parameters caused by cementitious material hydration during long-distance transportation of mine backfill slurry, rheological tests of backfill slurry were conducted at a constant temperature of 25 ℃, and the abrupt change law of the yield stress of cement-based backfill slurry at key nodes was revealed. A modified Darcy-Weisbach equation was derived, and an innovative design method for backfill pipelines based on time-varying rheology and sectional resistance was proposed, which was then validated through a 5 km backfill pipeline engineering case. The results are concluded as follows. Firstly, the higher the cement-sand ratio is, the earlier the abrupt change node appears, and the initial yield stress of backfill slurry with a high cement-sand ratio is higher than that with a low cement-sand ratio. Secondly, as the hydration time extends, excessive hydration products cause particle agglomeration and densification of the microstructure, leading to an increase in the plastic viscosity of the slurry and a significant increase in pipeline friction resistance. The greater the cementitious material content, the more obvious the change. Thirdly, compared with the conservative scheme, the time-varying sectional design scheme improves the safety margin of the backfill pipeline by 28.5%, and reduces the pipeline cost and annual energy consumption cost by 22.6% and 26.1%, respectively. The research results can provide a theoretical basis for the construction of mine backfill systems.

To address the influence of blasting fragmentation size on the comprehensive production costs of drilling, blasting and loading haulage in underground metal mines, 15 large-diameter long-hole stopes of a lead-zinc mine were taken as the research object. Based on measured blasting fragmentation size and production costs over the same period, a coupling model of direct operation costs of drilling-blasting-loading haulage was constructed, and sensitivity analysis and field industrial tests were conducted for verification. The results show that the comprehensive cost first decreases and then increases with the increase in average fragmentation size. The economic optimal fragmentation size is 24.99 cm, corresponding to a comprehensive direct operation cost of 7.501 yuan/t. When the explosive consumption per unit and blast hole pattern parameters are respectively perturbed by ±10%, the optimal fragmentation size remains within the range of 23 to 27 cm, and it is recommended to take 25 cm as the design target for on-site blasting fragmentation. Compared with the reference fragmentation size of 32.2 cm predicted by the Kuznetsov model, the predicted cost corresponding to the model's optimal fragmentation size is reduced by 3.09%. The average fragmentation size in the field test is 246.5 mm, which is 10.1% lower than that of the comparison stope, and the proportion of blocks larger than 600 mm decreases from 10.33% to 5.48%. The model is applicable to mines with similar geological conditions, mining methods, and equipment configurations, and its results only reflect the direct operation costs of the three processes of drilling, blasting and loading haulage.

Due to changes in physical and mechanical properties, the frozen rock mass in cold regions has a significant impact on rock fragmentation by blasting. To investigate the influence law of rock freezing temperature on the fragmentation characteristics of bench blasting, taking an open-pit mine in a cold region as the engineering background, a numerical simulation study on blasting was conducted using ANSYS/LS-DYNA software. Taking the normal temperature rock mass condition as a comparison, the influences of different freezing temperatures on blasting stress wave propagation, blasting crack distribution range, and rock mass damage and failure were mainly analyzed. The research results show that in terms of stress wave propagation, freezing temperature has a significant impact on the dynamic response of rock. As the rock freezing temperature decreases from 20℃ (normal temperature) to -30 ℃, the elastic modulus of the rock mass increases, and the stress wave velocity and stress amplitude increase by 27% and 20%, respectively, while the attenuation coefficient shows no significant change. In terms of blasting crack distribution range and rock mass damage and failure, the mechanical parameters of bench frozen rock mass in cold regions, such as compressive strength and elastic modulus, are higher, which has an adverse effect on rock fragmentation by blasting. In particular, for the frozen rock mass at -30 ℃ in the upper part of the bench, compared with the normal-temperature rock mass, its fracture zone range decreases by about 29%, and the reduction in damage and failure volume reaches 22%. The research results can provide a theoretical basis for the optimization of bench blasting parameters of frozen rock mass in cold region open-pit mines.