Several pieces of hard paper with different numbers, dip angles and widths were embedded into specimens to simulate structure of closed joint in rock masses and prepare rock mass models with different joints. Effect of joints on blast-induced failure characteristics of rock mass was analyzed with a high-speed camera and a 3D laser scanner, so as to explore the rules of crack propagation and fragment size distribution during rock blast. It is found that joints can disperse blasting energy and hinder crack penetration, leading to a decrease in the average size of blast-induced fragments as the number of joints increases. Wider joints can make diffraction and reflection of stress waves much more complicated, intensify energy dissipation, and also hinder crack propagation；while joints with small width are prone to make blast-induced fragments smaller in size. The interaction between joint dip angle and the propagation direction of the blast stress wave can significantly affect the crack propagation mode, and excessively large dip angles can easily hinder stress wave propagation.

Marmatite was calcined and then used as photocatalyst to degrade organic dye methylene blue (MB) under ultraviolet (UV) light irradiation. The degradation mechanism of this photocatalyst was investigated by using UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS) and performing free radical capture experiments. It is found that the marmatite calcined at 660 ℃ exhibits a great photocatalytic property, with the degradation rate of MB up to 98.46% within 240 min. In the calcined marmatite products, the ternary heterojunction is more conducive to the effective separation of photogenerated charge carriers than the binary heterojunction, thus leading to an improved photocatalytic performance.

As for rainfall-induced landslides in Mayang, Yuanling and Luxi counties within the red-bed region of the Yuanma Basin in Hunan Province, a correlation between landslides and rainfall were analyzed. Based on the E-D threshold model, the daily rainfall (R) was introduced as a third indicator to construct an E-D-R threshold model, thereby rainfall thresholds were determined for the Yuanma Basin. The study area was divided into warning units with the Thiessen Polygon method, enabling a county-level, unit-based graded warning response. The results show that the period from four days before a landslide to the day of the landslide represents the critical rainfall period for inducing landslides in the Yuanma Basin, and it is deemed appropriate for the effectiveness coefficient (α) of the rainfall to be 0.5. Compared to the two-dimensional E-D threshold model, the three-dimensional E-D-R threshold model demonstrates higher precision and offers greater accuracy and reliability in landslide risk assessment. The grid-based and refined division of warning units not only enhances the refined management and control capabilities of meteorological warnings for landslide disasters, but also facilitates unit-specific differentiated warnings in future forecasting by integrating predicted rainfall and rain information.

In order to accurately know the progress in frontier technologies and research hotspots in environmental monitoring and protection during deep-sea mining, after the patents and academic literature from January 1, 2005 to April 14, 2025 in the filed of deep-sea mining were retrieved with IncoPat and Web of Science, a statistical analysis was performed with bibliometric methods for 542 published patents and 469 academic literature, and then the development trend in this field was also discussed. It is shown that a synchronous increase in both patents and academic literature highlights the support of basic research for technological innovation. By formulating corresponding policies and through institutional collaboration, China has shifted its place from following others to keeping pace and even leading the pack in theoretical research. China has also put emphasis on the technologies of environmental monitoring and protection in its scientific research on deep-sea mining, and established a technical system and theoretical framework with in situ observation technologies for environmental impacts during deep-sea mining at the core. As a result, the research perspective has shifted toward understanding of complex system mechanisms. In the future, the environmental monitoring and protection system for deep-sea mining will be composed of four core modules, including environmental monitoring, environmental assessment, environmental management and environmental protection, and form an ecological risk supervision and management framework through the whole mining process, which will also be continually updated.

A kind of silver concentrate in Henan Province has the associated lead therein with an average grade around 7%, lower than the grade for pricing. A classification test was conducted with a hydrocyclone for the silver concentrate, and effects of parameters, including cone angle, underflow orifice diameter, and angle-cone ratio, on the classification and concentration of silver concentrate were explored. It is found that by adopting a 100 model hydrocyclone with cone angle of 60°, feed in a mass fraction of 13.89% to be fed at the pressure of 0.2 MPa, overflow pipe of 22 mm in diameter, and the underflow orifice of 12 mm in diameter, a high-lead silver concentrate grading 6316.29 g/t Ag and 12.39% Pb can be obtained at corresponding recoveries of 79.06% Ag and 79.45% Pb, with a yield of 49.25%; meanwhile, a low-lead silver concentrate with silver grade of 1 623.36 g/t can be obtained. This processing technique can obtain both high-and low-lead silver concentrate at the same time, leading to the economic value of the silver concentrate improved by 687.96 Yuan per ton.

A prediction method for mineral processing indices of shaking table was proposed based on eXtreme Gradient Boosting (XGBoost). As for the separation product zone, it can quantify the colour difference by colour moments, the shape characteristics by image moments, and the texture characteristics by evaluation indices of grey-level co-occurrence matrix, including contrast, homogeneity, correlation and ASM energy. The features of the separation product zone can be effectively extracted according to the difference in its colour, shape and texture during separation process. Subsequently, those features can be filtered by employing XGBoost, with which a prediction model can be then constructed. After being trained with the test set to predict the grade, recovery rate and yield of concentrate, this model can achieve accurate prediction of separation indices. It is found that the XGBoost-based model outperforms the decision tree model and random forest model in terms of accuracy when applied for predicting recovery and yield of concentrate.

A process for continuous producing lithium carbonate from spodumene was presented based on the processing technique including converting natural spodumene into β-spodumene for roasting, and sulphation roasting. Aspen Plus software was adopted to simulate the whole production process, with the parameters optimized as follows: H₂SO₄ and Li₂O in a molar ratio of 1.1, liquid-solid ratio of 2.0, and temperature for lithium precipitation at 85 ℃. Under the above conditions, lithium carbonate product can be finally produced with purity of 99.55% (in a mass fraction), presenting lithium recovery rate at 87.7%. The energy consumption of natural gas, pure water and steam is 0.42, 6.64 and 0.72 per unit of lithium carbonate product respectively.

In order to improve the surface hardness and wear resistance of Ti-6Al-4V alloy, a cladded coating of TiO₂ and TiN was prepared on the surface of Ti-6Al-4V alloy by laser cladding, and the microhardness, wear resistance, microstructure and element distribution of the coating were explored. Compared to the substrate, the surface hardness and wear resistance of the coating are significantly improved. It is shown that with TiO₂ and TiN powder in a mass ratio of 1∶9, the hardness and specific wear rate of the coating can reach 1 936.1HV_0.1 and 2.06×10^-14 mm³/(N·m), respectively, which are 5.4 times and 3.26 times those of the substrate. The main components of the coating include α-Ti, TiN, and TiN_0.6O_0.4, which is the reason for the significant increase in hardness and wear resistance of the TiO₂-TiN cladded coating. The research results provide a theoretical and experimental basis for improving the hardness and wear resistance of Ti-6Al-4V alloy by laser cladding technology.

An experiment was carried out for extraction of zinc from the tailings of lead flotation by adopting sulfuric acid leaching, and effects of grinding fineness, addition of sulfuric acid, leaching temperature, leach time, stirring speed and liquid-solid ratio on zinc leaching rate were investigated. The results show that the lead flotation tailings with the grinding fineness of -0.074 mm 75% are subjected to 1.5 h leaching at 60 ℃ by adding 15% sulfuric acid with stirring speed at 200 r/min, liquid-solid ratio of 3.0 mL/g, resulting in zinc leaching rate of 90.71%. The obtained leachate has Zn at the concentration of 18.94 g/L, and high content of Cd, Fe, Mn, Ca and Mg, which needs attention in the subsequent purification and enrichment operation.

A complete set of mineral processing technology was proposed for beneficiation tests of a beach placer with TiO₂ grade of 3.33% and Cr₂O₃ content of 0.36%. After a pre-concentration comprised of a gravity separation, a low intensity magnetic separation and a medium intensity magnetic separation, the rough concentrate was processed by roasting followed by dry magnetic separation, producing a titanium concentrate with TiO₂ grade of 47.72%, Cr₂O₃ grade of 0.071% and TiO₂ recovery of 64.76%. It is concluded that the goal to prepare qualified titanium concentrate by extracting titanium and reducing chromium can therewith be achieved.