An improved algorithm combining Rapidly-Exploring Random Trees (RRT) and Artificial Potential Field (APF) was proposed for obtaining an overall path planning for deep-sea collector vehicles. Based on the kinematic model of the collector vehicle, the RRT sampling mechanism was optimized by a target-biased strategy, and an adaptive repulsive coefficient was introduced to improve the potential field function, thereby enhancing obstacle avoidance and target reachability. Verification was carried out by simulation under two different working conditions. The results show that in Condition 1 (complex environment), the RRT^*-APF algorithm has its searching time shortened by 73.1%, the number of expanded nodes reduced by 50.7%, and the path length shortened from 1 542.35 m to 1 486.16 m compared to the RRT^* algorithm, being more suitable for complex environments. In Condition 2 (simple environment), the RRT-APF algorithm has its searching time shortened by 67.4%, the number of expanded nodes reduced by 52.6%, and the path length shortened from 973.58 m to 910.27 m compared to the traditional RRT algorithm, being more suitable for simple environments.

To precisely regulate the performance of site mixed emulsion explosive (SMEE), influences of key parameters, including aqueous phase (ammonium nitrate/water), oil phase (diesel oil/engine oil), shear rate and proportion of sensitizer, on the performance of SMEE were systematically investigated. A quantitative correlation model describing the variation of charge density and detonation velocity with various factors were established by means of multiple linear regression and path analysis. The results show that moderately increasing content of ammonium nitrate or reducing water content can significantly improve the detonation velocity; increasing the proportion of engine oil in the oil phase or reducing the proportion of diesel oil can enhance the energy output of explosive. A higher shear rate can reduce the internal phase particle size of emulsion, thereby increasing detonation velocity; however, a larger proportion of sensitizer can lead to a decrease in detonation velocity. Path analysis results indicate that priority should be given to the proportion of sensitizer and content of ammonium nitrate in regulation of detonation velocity of emulsion explosive, while both the proportion of sensitizer and shear rate should be taken into consideration in adjusting charge density.

The evaluation indices for open-pit mine slope stability are characterized by variability, randomness and fuzziness. To overcome the defects of traditional methods in open-pit mine slope stability evaluation, such as static index weights, insufficient correlation processing and poor handling of index differences, a multi-level and multi-variable dynamic evaluation model was constructed for open-pit slope stability by improving extension cloud model, replacing the standard deviation in the traditional CRITIC method with the coefficient of variation, revising the independence coefficient of evaluation indices, and introducing correlation matrix into dynamic weight calculation. Then, three high and steep slopes in an open-pit mine were evaluated using this model. The results show that the safety grade limit values of those three slope areas are 3.38, 3.23 and 3.37 respectively, with confidence factors all less than 0.05, thus being graded as Class III and considered to be basically stable. It is found that the evaluation results are basically consistent with those obtained by using rigid body limit equilibrium method, extenics theory and unascertained measure theory, which verifies the applicability and reliability of the proposed model.

Reasonable axial length of an air column can lead to crack penetration between adjacent blast holes without generating crushed zone on hole wall, which plays an important role in presplit blasting. The variation characteristics of initial impact pressure on the hole wall along the axial direction of blast hole were analyzed by theoretical calculation. For the blasting engineering of Barun Open-pit Mine, a reasonable axial length of air column for presplit blasting was preliminarily estimated to be about 1.5 m, and then the variation of stress after blasting with different axial lengths of air column was analyzed by numerical simulation. The results show that the initial pressure on the hole wall in the air column section presents a "U-shaped" distribution along the axis of blast holes, and the minimum pressure exists at the middle of the air column. When the axial length of an air column is 1.5-2.0 m, the numerical simulated stress oscillates when it drops to about 10 MPa, which can meet the requirements of crack initiation and propagation between rock holes. The engineering practice in the stope of Barun mine shows that when the air column length is 1.5 m, the slope roughness after presplit blasting is less than 10 cm, the half-hole mark rate greater than 85% and the resultant velocity of blasting vibration is 5.782 cm/s, presenting excellent indicators.

Precision blasting technology was studied based on classification of rock mass blastability aiming at slow drift advance by blasting in stope and high unit consumption of explosive in Xincheng Gold Mine. By analyzing indices such as uniaxial compressive strength, rock mass integrity coefficient and rock density, a blastability classification model with multi-parameters was established, and the rock mass blastability was divided into 5 levels based on the proposed modified BQ index formula. It is found the ore rocks in Xincheng Gold Mine are mainly rated as level Ⅲ (intermediate) and level Ⅳ (difficulty) in terms of ore blastability, for which blasting parameters were then optimized respectively. Industrial experiments show that after optimization, the blasthole utilization rate for stope drifts was increased from 87.3% to 93.9%, and overbreak was reduced, including the over-width down from 17.5% to 1.25% and the over-height down from 25.0% to 3.3%. It is shown that smooth blasting and precise control of surrounding rock disturbance can be actualized.

For solving noise interference in the measured blasting vibration signals, a noise reduction technique is proposed. Based on the Intrinsic Time-Scale Decomposition (ITD) algorithm, the signal is firstly decomposed into several Intrinsic Mode Functions (IMFs). And the K-means clustering is then used to calculate the correlation coefficient value for identifying the types of signal with noise. The wavelet packet method is used to denoise and reconstruct the types of signal with noise, so as to obtain desired signal. This technique was used to verify the noise reduction effect for both simulated and measured signals. The results show that in the noise reduction test for simulated signals, the ITD - K-means - wavelet packet method can achieve the highest signal-to-noise ratio (17.241 dB) and the smallest root mean square error (9.71×10^-2), compared with the traditional wavelet packet method, the CEEMDAN method and the ITD method. The noise reduction test for measured signals shows that after processing with the ITD - K-means - wavelet packet method, the signal in the low-to-medium frequency band (0-60 Hz) can retain more energy of dominant frequency, thus high-frequency noise (>120 Hz) can be effectively suppressed.

For the first phase shaft project in the underground mining of Aurora Gold Mine, a discrete element method software EDEM was adopted, and a water-rock-soil coupled model for instability of shaft surrounding rock was established using the smoothed particle hydrodynamics discrete element coupling method (SPH-DEM), for investigating the instability evolution process of strongly weathered surrounding rock under effect of seepage. The results show that the surrounding rock of the shaft become significantly instable within 2-6 s, and the average moving velocity increases firstly and then decreases, peaking at 0.155 m/s; the fluid force acting on the shaft wall fluctuates sharply during 0-2 s and then gradually stabilizes. The shaft wall suffers large scale shallow abrasion, with a final wear area of 17.404 43 m² and volume of 0.013 31 m³. Numerical simulation shows that the angle of repose for the collapsed shaft surrounding rock is 25°, presenting a relative error of only 1.88% compared to the on-site practical measurement, which has verified accuracy and practicability of such SPH-DEM method.

With the open-pit mine slope of Sijiaying Yanshan Iron Mine as an example, biotite granulite specimens from the deep parts of the eastern and northern slopes of the stope were selected for impact tests, freeze-thaw cycle tests and mechanical loading tests, and the fracture characteristics of biotite granulite with different damage degrees under the combined action of freeze-thaw cycles and loading were studied. The results show that under freeze-thaw action, both the mass loss rate and porosity of biotite granulite present approximately linear increase as degree of damage increases. For biotite granulite with different initial damage degrees, the uniaxial compressive strength and elastic modulus all decrease after freeze-thaw cycles. It is shown that intact biotite granulite under loading and freeze-thaw cycles is dominated by splitting failure, while biotite granulite with initial damage is dominated by shear failure and combined tensile shear failure.

With the lepidolite flotation tailings from Yichun of Jiangxi Province taken for search, effects of different combined processing techniques of magnetic separation and gravity separation on recoveries of tantalum, niobium and tin were compared based on its process mineralogy. It is found that the processing technique of magnetic separation combined with gravity separation, and stepwise gravity separation can lead to a Ta-Nb-Sn concentrate with higher grades but lower recoveries; while a combined process consisting of classification, gravity separation with spiral chute and then with a shaking table can produce a Ta-Nb-Sn concentrate with grades including 5.57% Ta₂O₅, 7.56% Nb₂O₅ and 45.63% SnO₂, at corresponding recoveries of 41.66%, 42.28% and 31.07%.

To enhance flotation efficiency of fluorite ore, (E)-N-(2-hydroxyethyl) octadec-9-enamide was synthesized and then compounded with sodium oleate to prepare a novel collector CYHS-7. Then, an experiment on flotation of fluorite with CYHS-7 and sodium oleate as collectors was conducted, and the results demonstrate that an appropriate pH for flotation process is at 9, and the optimal dosages of CYHS-7 and sodium oleate in a closed-circuit test are 175 g/t and 350 g/t respectively. In a laboratory flotation test, the recovery of fluorite was increased by 9.15 percentage points with the dosage of CYHS-7 at half that of sodium oleate.