Based on the detailed process mineralogy study of a kind of refractory gold ore, an experimental research was carried out for gold extraction. It is found that the gold mineral in such ore are fine-grained and dispersed in gold-carrying minerals. It is proposed that such refractory gold ore be processed with the technique of enhanced flotation, and an addition of regulator XPT511 can effectively improve the index of gold flotation. It is shown that a close-circuit flotation test results in a gold concentrate grading 22.91 g/t Au at 62.85% recovery.

An experimental study was performed on efficient separation of talc and molybdenite by adopting flash flotation. With grain fineness of 0.043-0.074 mm, 20 g/t of frother MIBC, and flotation time of 60 seconds, the talc recovery attains 76.64%, while the recovery of molybdenite is only 19.72%, resulting in an efficient separation between talc and molybdenite. According to the nonlinear fitting of flotation kinetic equation by MATLAB, talc flotation process conforms to the classic first-order flotation kinetic model, while molybdenite flotation conforms to the modified classic first-order flotation kinetic model. The following test on the influence of flotation time on adsorption of MIBC on talc and molybdenite shows that talc is more likely to interact with the agent than molybdenite at the early stage of flotation, and much more MIBC is adsorbed on talc than on molybdenite at that stage.

In order to utilize low-grade associated cassiterite resource from Huangshaping polymetallic ores, a new beneficiation process consisting of high-gradient magnetic separation (HGMS) for tailings discarding and tungsten-tin flotation for enhanced enrichment was developed based on the performed HGMS and flotation tests. After HGMS to pre-discard tailings, the loss rates of molybdenum, tungsten and fluorite were all less than 10%, while cassiterite was greatly enriched in the HGMS rough concentrates. Then, a flotation of reground HGMS rough concentrate was conducted by using Pb-BHA-SPA multiple ligand metal-based collector, producing a mixed tungsten-tin concentrate grading 0.627% WO₃ and 0.78% SnO₂, at corresponding recovery of 26.56% and 18.03%, respectively. This process provides a new idea and method for enhanced enrichment and effective utilization of low-grade associated cassiterite.

An experiment was carried out with a pelletizing and magnetization roasting process for fine-grained specularite to investigate the pelletizing process, as well as the roasting performance and effect of pellets in the process of magnetization roasting. The results show that by adopting a process of fine grinding and pelletizing followed by magnetization roasting with an additionally prepared reducing agent, under the condition of roasting at 810 ℃ for 60 min, and addition of charcoal at an amount of 2.5%, a concentrate grading 49.04% Fe at 76.99% recovery can be obtained. In comparison, with a process of direct pelletizing followed by 60 min magnetization roasting at 650 ℃ with additionally prepared reducing agent and addition of semi-coke at an amount of 3.0%, the concentrate grading 52.95% Fe at 85.07% recovery can be obtained. It is found that the processing technique consisting of direct pelletizing and magnetization roasting is simpler and can bring better processing indicators. It can provide a reference for on-site processing of fine-grained specularite by adopting magnetizing roasting.

In order to balance productivity against safety in the mining of high-level stope with gently-dipping and extrathick orebody, an iron mine adopting sublevel open stoping with backfill was taken as an example to optimize the mining sequence. Firstly, pillars was determined to at a reasonable spacing from 14.2 m to 47.2 m based on the theory of bearing capacity of pillars. Secondly, according to stope structure parameters, the pillars were designed to be 15 m, 30 m and 45 m in thickness, respectively. An orebody model was also established with FLAC^3D and then was used to analyze the roof subsidence and pillar stability based on comparison of each mining scheme. Finally, a judgment matrix of mining sequence was constructed based on analytic hierarchy process and fuzzy comprehensive evaluation method, with both factors of safety and productivity taken into consideration in the numerical simulation. The comprehensive membership degrees of those three schemes were calculated to be 0.86, 0.79 and 0.80, respectively, and pillars in the best scheme were determined to be in the thickness of 15 m. The results of an industrial experiment have proven that this scheme can ensure stope with relative stability while achieving the maximum production capacity.

Copper slag flotation tailings were taken as raw materials, and carboxymethylcellulose (CMC), bentonite, sodium silicate alone or the mixture were taken as binders to prepare copper slag pellet for reducing dust and flue gas generated during utilization of copper slag tailings. The effect of binder on balling was explored in terms of the drop numbers, compressive strength and cracking temperature of green ball, and microscopic morphology, adsorption characteristics and surface potential changes were also analyzed by scanning electron microscopy, infrared spectroscopy and Zeta potential detection. Results show that all three binders can be useful in agglomeration of copper slag tailings. When used alone, CMC, bentonite and sodium silicate are required to be added at an amount more than 0.20%, 2.0% and 2.5%, respectively. In case of CMC used in combination with bentonite or sodium silicate, bentonite or sodium silicate should be added at an amount of more than 2.0% and more than 2.5%, respectively, with the addition of CMC is at an amount of 0.1%；while with the addition of CMC at an amount of 0.15%, the addition of bentonite or sodium silicate should be more than 1.5% and more than 2.0%, respectively. With the addition of binder, the prepared pellet has more compacted structure and stronger spatial structure. It is found that copper slag tailings particles have a lower value of zeta potential, and an improved hydrophilicity, which can promote interparticle adsorption, and thus improves pellet quality.

In order to analyze mechanical properties of conveying hose during deep-sea mining operation, a mechanical model was established with Abaqus software for the buffer, flexible hose, and mining vehicle under different working conditions to analyze effects of buoyant ball position, buoyant force, ocean current velocity and volume fraction of conveyed mineral ores on hose configuration, as well as effect of forces that flexible hose exerts on the mining vehicle. When buoyant balls are put on the position far away from a mining vehicle, the hose is prone to be dragged on the seafloor；while being closer to a mining vehicle, the hose is prone to be entangled. It is shown that the closer to a mining vehicle, the greater the buoyant force and the greater the forces that the hose exerts on the mining vehicle. Furthermore, slower current velocity is more likely to bring greater impact to the hose configuration. The velocity of ocean current will influence the direction, magnitude and variation of the forces exerted on the mining vehicle. It is suggested that with ocean current at a velocity of 0.2 m/s, buoyant balls should be put on the position 12 m away from the buffer, with buoyant force selected at 1 500 N. In this case, the maximum horizontal and vertical tensile forces of the hose on the mining vehicle are 941 N and 1 258 N, respectively.

In order to know the status quo of technologies for deep-sea mineral resources development, the related patents were briefly analyzed. A total of 3 236 patents regarding deep-sea mineral resources development technologies published worldwide from 2000 to 2023 were taken from the incopat global patent database, and analyzed in terms of number of patent applications, geological distribution, subdivision of technologies, time of Chinese patents applications, as well as nationalities of Chinese patent applicants among others. It is found that the patents regarding deep-sea mineral resources development are mainly from China, United States, Korea, Russia and Japan, focusing on technologies including detection system, mining system and transportation system. In recent years, Chinese patent applicants have gradually predominated in the related patent application worldwide, reflecting China's great potential in R & D and market expansion of deep-sea mineral resources development technologies.

A heap leaching test was carried out for the low-grade copper-cobalt oxide ores from Congo (DRC), and effects of spray intensity, spray acidity and ore particle size on the leaching rates of copper and cobalt were investigated. The results show that both acidity and intensity of spray bring significant impact to the speed and cumulative rates of copper and cobalt leaching, while the ore particle size has little effect on leaching process. And finally, the optimal conditions for heap leaching of low-grade copper-cobalt ore were determined, including spray acidity at 20 g/L, spray intensity of 15 L/(m²·h), and ore particle size of less than 40 mm. It is shown that the cumulative leaching rates of copper and cobalt can reach 90.89% and 82.27%, respectively, after 100 days of heap leaching.

The effects of separate and combined usage of NaClO and KMnO₄ on the flotation separation of chalcopyrite and pyrite were investigated by performing flotation and adsorption tests, infrared spectroscopy (IR) and XPS analysis. The results show that selective separation of chalcopyrite and pyrite can be achieved with NaClO and KMnO₄ in a ratio of 10∶1, the total oxidant dosage of 70 mg/L, pulp pH of 10, and oxidation time of 3 min. It is shown that the recovery of chalcopyrite can exceed 92%, while the recovery of pyrite is less than 8%. The IR and XPS analyses show that a combined usage of NaClO and KMnO₄ obviously changes the surface property of pyrite, resulting in hydrophilic oxidized substances on the surface, such as iron oxide, iron hydroxide and iron sulfate, which impedes the adsorption of collectors, thus reducing floatability of pyrite. The chalcopyrite surface remains mildly inert to NaClO and KMnO₄ under certain conditions. Consequently, the adsorption of xanthate on chalcopyrite is remarkably higher than that on pyrite, which favors their flotation separation.