In Bangzhong Zinc-Copper Mine in Tibet, a mining method consisting of stoping followed by backfilling is adopted to excavate ores. In order to further improve production efficiency and economic benefits in the mine, rock mass quality was classified based on the investigation of geoengineering and geomechanics and rock mechanics test, and key factors influencing stability of stopes were analyzed in combination with the layout of mining and cutting engineering. On this basis, stope structure parameters were optimized by using a variety of empirical stability charts. The results show that the improved stability chart is highly adaptable and a stop with span extended from 12.5 m to 20 m can still meet safety requirement in the mining production.

Based on an introduction of Japan's operation mechanism for exploiting deep-sea mineral resources, including Japan's marine policies, management and implementation agencies related to ocean mining, as well as Japan's coordination mechanisms for pushing progress in ocean technologies, Japan's cross-ministerial Strategic Innovation Promotion Program is outlined in terms of ocean mining, and the research achievements made by Japan in this field are also summarized. Such research on Japan's management system and program for exploitation of deep-sea mineral resources can be of reference for China in developing strategies, formulating investment mechanism and coordination mechanism for deep-sea mining.

The out-of-life saggar after repeated use for LiCoO₂ sintering in industry was taken to explore its erosion mechanism during high temperature synthesis of LiCoO₂ by adopting fluorescence analysis, chemical composition analysis, X-ray diffraction analysis, microstructure and energy spectrum analysis. Results show that when saggar is used to hold basic cobalt carbonate and lithium carbonate and calcined at 950 ℃ for 15 h, it is eroded and damaged after 15 times of operation. During LiCoO₂ synthesis, saggar is mainly eroded by lithium ions, with the dominant erosion products including tetragonal LiAlO_2, α-LiAlO_2, LiAlSiO_4, Li₃AlSiO₅ and Li_3.17Si_0.7S_0.3O_4. Cobalt ions are not involved in the chemical erosion but the synthesized lithium cobalt compounds migrate along the pores and also deposit along the migrating pores of saggar.

With gold tailings as aggregate and ground gold mine tailings (referred to as gold mine tailings powder) as precursor materials, a kind of backfill material was prepared by alkali activation with sodium hydroxide together with sodium silicate as an activating agent. The effects of several factors, including particle size of gold mine tailings powder, modulus and addition of activating agent, on the mechanical properties of backfill mass were studied. The test results show that when gold mine tailings is ground for 60 min (size d₅₀ of 5.939 μm), modulus and addition of sodium silicate in activating agent are 1.2 and 60% respectively, the prepared backfill mass can have a 28 d compressive strength of 854.2 kPa, completely up to the requirement for backfill mass stipulated in the GB/T 39489—2020 "Technical Specification for Paste Filling with Total Tailings". Due to alkali activation, gold mine tailings powder is subjected to a hydration reaction, yielding a large amount of aluminosilicate gel, which forms a dense and stable structure, resulting in the backfill mass with good mechanical properties.

A flotation experimental study was conducted to process a copper sulfide ore. A closed-circuit flowsheet consisting of copper preferential flotation and sulfur recovering from copper flotation tailings was adopted, resulting in a copper concentrate grading 23.01% Cu at 95.47% recovery and a sulfur concentrate grading 35.72% S at 58.48% recovery.

The predominant minerals in a kind of high siliceous non ferrous metal tailings include quartz, alunite, dickite, sericite and pyrite. The quartz has relatively coarser grain size, while alumite and dickite are enriched in a relatively finer fraction. Furthermore, alunite, quartz, dickite and sericite minerals are complicatedly disseminated. Herein, tests were conducted to reclaim alunite and quartz therefrom. An alunite concentrate with SO₃ grade of 20.14% can be obtained by using a process consisting of desliming, desulfurization and alunite flotation. And then, the obtained alunite flotation tailings are subjected to a reverse flotation, yielding a quartz concentrate grading 96.38% SiO_2. It is shown that this flowsheet can actualize an efficient and comprehensive utilization of nonferrous metal tailings.

A micro- and nano-indentation test was performed for CoCrFeNiMn high entropy alloy. The relationship between the geometrically necessary dislocation (GND) density of CoCrFeNiMn and reciprocal value of real indentation depth (1/h) was obtained under different working conditions, and the influence of elastic factor (Δe) on GND density was also explored. The results show that GND density with the consideration of elastic deformation (ρ_Ge) presents a nonlinear relationship with 1/h, while GND density without the consideration of influence of elastic deformation (ρ_G) has a linear relation with 1/h. Based on the comparison of variation of ρ_G/ρ_Ge with the indentation depth, it is found that the ratio of ρ_G/ρ_Ge is 3-4 when the indentation depth is less than 500 nm, indicating that elastic factor can have an obvious impact on the GND density at shallow indentation. And, the ratio of ρ_G/ρ_Ge is approaching 1 when the indentation depth is up to 3 000 nm. It is shown that as indentation depth increases, dislocation slip gradually dominates deformation.

Based on the relevant patents of layered cathode materials for sodium-ion batteries in China, a review of patent applications (authorization) is presented in terms of annual trend and main applicants. Also, some representative patents on precursors, structure, chemical washing and coating of layered cathode materials for sodium-ion batteries are chosen for analysis, Finally, the industry development trend, as well as technical difficulties and hotspot in this industry are summarized.

Based on the calculation theory of solid-liquid two-phase flow and consideration of collision effect, a hydrodynamic model was established by using VOF model, and reamer operation under different working conditions was also analyzed by numerical simulation. It is shown that a reamer working with an inclination angle of 45° can have a good effect, resulting in percentage of disturbed area at 68.32%. As the rotating speed of reamer increases, disturbance of the waters above a reamer gradually becomes violent, and the scope of waters being disturbed also gradually becomes wider first and then narrows down. It is concluded that a reamer should work with an inclination angle of 45°, rotate at a speed of 45 r/min and move laterally at a speed of 0.2 m/s, which can reduce disturbance to the waters brought by its operation, thus minimize the secondary pollution to the waters to a certain extent.

In order to define a mutual disturbance range between the upper and lower ore belts of a copper-gold mine during 8-year co-mining period, a deformation law of stratum by natural caving mining method is summarized based on the characteristics of stratum movement and deformation induced by mining. Combined with the actual mining technologies on site, a law of rock movement is explored for the lower ore belt by adopting engineering analogy method, theoretical calculation method and numerical simulation method, and the critical mining-induced disturbance range is defined to ensure safe mining of the upper ore belt, which provides a basis for the planning and layout for the mining of the lower ore belt. It is found that for safe mining of the upper ore belt, the lower ore belt should have security pillars of about 550 m along the strike, with the minimum angle of stratum movement within the range from 70° to 73.3°.