The concentration of plume caused by hydraulic collecting system during deep-sea polymetallic nodules mining under different working conditions were analyzed. Test results show that the concentration of discharged plume from conveying system is much higher than that of sediment plume caused by the disturbance of capture system, which is one of the main causes of turbidity current in the sea. In the test, the curve of slurry concentration presented a steep upward trend line followed by a steep downward line. Increasing oil pressure of the pump of capture system will lead to higher concentration of slurry. However, the oil pressure of the pump of conveying system won't result in obvious variation in slurry concentration.

In order to explore disturbance of seabed sediment during mining of polymetallic nodules, a pool experiment was carried out to scour sediment by a waterjet from polymetallic nodules collector. Variation of gully depth, and migration and diffusion regulation of sediments were investigated in the experiment by setting the waterjet at different speed, with nozzle at different height from sediment, and collector at different traveling speed. The results show that the collecting process of polymetallic nodules brings scour to both particles and blocks of sediment, leading to uneven surface of the gully. Then, disturbed sediment migrates and diffuses through upper plume flow and bottom gravity flow.

Microseismic signals collected during roadway construction in Jinfeng Gold Mine in the southwest Guizhou Province are non-stationary and also contaminated with background noise. For solving this problem, a noise reduction method based on the improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) combined with blind source separation (BSS) was proposed. With this method, a microseismic signal can be preliminarily decomposed by ICEEMDAN algorithm, and then correlation coefficient and marginal spectrum of signal can be calculated with MATLAB. Components of noise-containing mode and main frequency of signal can be filtered, and FastICA algorithm is finally used for BSS to achieve noise reduction. The practical application in mine shows that compared to empirical mode decomposition (EMD) and traditional wavelet packet threshold method, the proposed method, with higher signal-to-noise ratio (24.142 5 dB), can bring better noise reduction effect with smaller standard error (0.012 18).

In consideration of safety problem of landfilling into a dump with inclined foundation in an open-pit mine, an inclined foundation model and an anti-slide coal pillar model were established based on the analysis of landfilling methods in such inclined dump, deformation characteristics and sliding mode of inclined foundation, and then the method for evaluating stability of anti-slide coal pillar and influencing factors of the stability coefficient of dump slope were all discussed. The research results show that the stability of anti-slide coal pillar mainly depends on the relationship between the internal friction angle of coal pillar and the rest angle of waste material. When the internal friction angle is greater than or equal to the rest angle, the stability coefficient of dump slope increases with an increase in the length of anti-slide coal pillar; while when the internal friction angle is less than the rest angle, the stability coefficient of dump slope increases first, then falls down and finally increases again as anti-slide coal pillar becomes longer.

In view of the data of ground-based SAR presenting high oscillation and high fluctuation with less obvious characteristic trend, an approach for early warning and prediction of slope deformation by using velocity reciprocity was proposed, which adopts a data processing method of subtracting dislocations and deleting limits to optimize the quality of deformation data, thus the accuracy of early warning and timely prediction of landslide can be improved. The application of this approach in an iron mine in Inner Mongolia shows that not only those problems faced in the actual actuation can be solved, but also the data about disaster approaching can present obvious deformation rule. It is concluded that this early warming and prediction approach has a wide application.

In order to find a more accurate and efficient way to measure volume of explosion-produced craters, the traditional method by using a reference plane with a vertical section was improved. Taking the crater produced by single-hole blasting of the deep orebody in Gaofeng Mine as an example, the measurement result by using 3D laser scanning was compared to that by using a reference plane with a vertical section. It is found that 3D laser scanning measurement is superior in terms of accuracy, efficiency and measuring operability. This research can provide a new idea for accurately measuring the volume of explosion-produced craters.

The motion of spherical, tetrahedral and hexahedral particles flowing in a vertical pipe under different working conditions was simulated by using computational fluid dynamics-discrete element method (CFD-DEM), and the motion of irregular particles flowing in a vertical pipe was obtained. Based on comparison of local concentration and local flow rate, it is found that with lower flow rate at the inlet, the shape of particles can bring a larger influence to local concentration; while with a higher feed concentration and lower inlet flow rate, the shape of particles can bring obvious influence to local flow rate.

Response surface methodology (RSM) was used to optimize the flocculation settlement parameters of fine iron tailings slurry. According to the Box-Behnken test method in Design-Expert 8.0 software, a three-factor and three-level test was designed to obtain a regression equation of turbidity model for flocculation settlement of fine-grained iron tailings slurry. The results show that with the following favorable flocculation settlement parameters, including addition of inorganic flocculant FeCl₃ at an amount of 113.44 mg/L, organic flocculant PAM at an amount of 0.61 mg/L and stirring speed of 440.57 r/min, the slurry turbidity is predicted to be 11.45NTU, while the measured value is 12.38NTU, indicating that the model has a good accuracy with a small error. Based on the model variance analysis, reliability analysis and factor interaction analysis, it can be verified that RSM is reasonable and feasible to be used for optimizing the flocculation settlement parameters of fine iron tailings slurry, which can provide theoretical basis for its efficient treatment.

A technique featuring separated treatment and recycling was introduced to process a mineral processing wastewater from a tungsten-copper ore concentrator. The wastewater from copper tailings precipitation and copper concentrate filtration is recycled for copper flotation, while the water from tungsten concentrate filtration is returned to the cleaning stage in tungsten flotation. They all can meet the water quality requirement in beneficiation. Tungsten tailings water can be reused in grinding and tungsten flotation after intensified treatment by lime flocculation and Fenton oxidation processes. In a close-circuit test, each type of wastewater from different beneficiation processes was separately returned to the corresponding stages based on its quality, and the obtained technical indicators were equivalent to those from the tests with fresh water.

The interaction mechanism of kyanite group minerals and quartz in cationic flotation system was studied by using an extended DLVO (EDLVO) theory combined with microscopy analysis. The results show that, under conditions including pH value of 8, FeCl₃·6H₂O dosage of 30 mg/L and dodecylamine dosage of 80 mg/L, there is interaction between quartz and kyanite group minerals in various size fraction, and the adhesive coating among particles is one of the main reasons for the interaction between kyanite group minerals and quartz amidst flotation process. Besides, the adsorption force between kyanite group minerals and quartz is in the following descending order：andalusite/quartz ≥kyanite/quartz ≥ sillimanite/quartz, indicating that it is relatively difficult for andalusite to be separated from quartz by flotation.