CHINA MINE ENGINEERING

Abstract:Blasting in bench operations is widely used in mining and infrastructure construction, but its vibration effects pose a serious threat to the safety of adjacent facilities. Accurate prediction of the peak vibration velocity induced by blasting is crucial for ensuring engineering safety. Addressing the limited generalization ability of traditional empirical formulas and single machine learning models, this study proposes an integrated prediction model that combines the Sand Cat Swarm Optimization (SCSO) algorithm with Categorical Boosting (CatBoost) to enhance prediction accuracy. Experimental results demonstrate that optimizing the CatBoost model with the SCSO algorithm significantly improves prediction accuracy. This model performs excellently across multiple datasets, providing a new and effective method for predicting peak vibration velocities in bench blasting and having potential for application in other related projects.

Abstract:The XGBoost ensemble learning algorithm has excellent performance in solving complex nonlinear relationship problems. In order to accurately predict the surface subsidence caused by mining, the genetic algorithm was introduced to optimize the XGBoost model, and the GA-XGBoost combined model was developed using the python programming language. Firstly, the hyperparameter vector of XGBoost is randomly initialized, the prediction error of the model is obtained after training and testing, and the XGBoost model is optimized by GA, and finally the XGBoost model with the best performance is obtained, and 78 domestic coal mining subsidence data are predicted. The prediction results show that the R2 (coefficient of determination) of the prediction results of the GA-XGBoost model is 0.9318, the RMSE (root mean square error) is 0.3989, and the MAE (mean absolute error) is 0.2989. Compared with ensemble learning models such as single XGBoost, random deep forest, and Gradient Boost, the GA-XGBoost model has higher mining subsidence prediction accuracy.

Abstract:Coal mine electromechanical equipment is an important factor that directly affects coal production efficiency. In order to accurately predict the safety evaluation level of coal mine electromechanical equipment, three main influencing factors are proposed, namely enterprise organizational management factors, coal mine underground environmental factors, and electromechanical equipment status factors. Four safety evaluation level indicators are established, and a CNN-SVM model is constructed to classify and predict the characteristic values of coal mine electromechanical equipment factors with multiple vectors. The results showed that the training and prediction results of CNN-SVM model were similar to those of CNN-GRU model and CNN BiLSTM model, both of which had slightly lower prediction accuracy for safety level III. However, the prediction accuracy of this model for safety level III was higher than the above two models. Especially in the test set prediction results, the prediction accuracy of safety level III was 96.3%, far lower than the 77.8% and 88.9% of CNN-GRU model and CNN BiLSTM model. The overall prediction accuracy of CNN-SVM model for coal mine electromechanical safety evaluation level was higher than the other two models, and the model prediction results were basically consistent with the actual evaluation results.

Abstract:As underground resource extraction progresses deeper, the rheological behavior of surrounding rock in tunnels has become increasingly prominent, emerging as one of the main challenges restricting the effectiveness of deep tunnel support. Taking the rail roadway of the Hudu coal mine in Jincheng as the research object, this paper investigates the control mechanism of rheological deformation in deep tunnels through theoretical analysis, and validates the theoretical findings using FLAC3D numerical simulation software. The research results indicate that the effective control of tunnel rheology is closely related to the interaction between support reaction forces and geological stresses. By reasonably increasing the support strength, the development trend of surrounding rock rheology can be significantly suppressed. This study provides an important reference for the stability control of deep tunnels.

Abstract:In order to study the stability of surrounding rock after tunnel support in a large-section circular tunnel excavated by a shield tunneling machine, the No.1 return air shaft of the South Six mining district in Yuwu Coal Mine is used as the engineering background. The theoretical analysis provides a basis for selecting the support parameters. Based on the Hoek-Brown strength criterion, the radius of the loosened zone of the surrounding rock in the 6.3-meter diameter tunnel is calculated to be 8.12 meters, and the radius of the plastic zone is 4.20 meters. Therefore, the tunnel support adopts an alternating rock bolt and tendon support system. Through tunnel monitoring, the support effectiveness is evaluated in depth by analyzing the roof separation, surface displacement, and the forces on the rock bolts (tendons). The results show that the tunnel mainly undergoes bottom-up deformation, with slight separation at the roof. The forces on the rock bolts range from 200 to 225kN, while the forces on the tendons range from 230 to 260kN, indicating that the stability of the shield-excavated circular tunnel is good and the support strength meets the requirements for tunnel usage.

Abstract:In the process of thick coal seam mining, section coal pillars are usually retained for roadway protection, which brings problems such as waste of coal resources and difficulty in roadway maintenance. In order to solve these problems, this paper proposes a method of non-pillar mining of prefabricated filling roadway side in fully mechanized top coal caving face. The numerical simulation method is used to establish a non-pillar mining model of prefabricated filling roadway side in fully mechanized top coal caving face. The stress distribution, displacement change and plastic zone distribution law of surrounding rock in the process of roadway excavation are studied. The results show that the excavation of the mining roadway will cause the stress redistribution of the surrounding rock, which will lead to the increase of the stress of the filling roadway side and the solid coal side; the prefabricated filling body in the roadway has a large supporting strength and anti-deformation ability, and its deformation is less than that of the solid coal side. The application of non-pillar mining method of prefabricated filling roadway in fully mechanized caving roadway can effectively improve the recovery rate of working face and reduce the deformation of roadway surrounding rock, which is of great significance to the study of non-pillar mining and roadway surrounding rock stability.

Abstract:In the process of coal seam mining, the problems of serious deformation of the roadway perimeter rock and the difficulty of support are prominent, which greatly affect the safe production and efficient operation of the coal mine.In this paper, we take 36405 working face of Xishan coal mine as a specific engineering background and carry out an in-depth research.We designed three types of roadway support schemes, and used Midas numerical simulation software to make a detailed comparative analysis of the deformation of the surrounding rock, the state of stress distribution, and the distribution range of the plastic zone in the roadway under these three different support schemes.After comprehensive evaluation, the preferred support scheme was finally determined and field tests were carried out. The field test shows that the deformation of the top and bottom slabs and the two sides of the tunnel enclosure is basically stable at 23.6mm and 15.2mm, which verifies the reasonableness of option 3.

Abstract:To accurately investigate characteristics of rocks in the non-linear accelerated creep stage, a novel non-linear viscoelastic-plastic creep model of rocks was established based on the memory-dependent derivative (MDD) theory and generalized to the three-dimensional (3D) space. The model was established by connecting the memory-dependent (M-D) dashpot, Hooke solid, and non-linear viscoplastic body formed by parallel connection of the plastic element and M-D dashpot in series. Under low stress, the Hooke solid and M-D dashpot can describe both the instantaneous and isokinetic creep characteristics of rock; when the stress exceeds the long-term strength of the rock, the non-linear viscoplastic body can manifest the non-linear accelerated creep characteristics of rocks. Creep data pertaining to shale, greenschist, and clay were used to compare the accuracy of the M-D creep model, fractional creep model, and viscoelastic-plastic creep model. The results show that the goodness-of-fit of the proposed model is better than other models in expounding creep deformation of rock and soil mass, with a particular advantage in characterizing non-linear creep of a rock and soil mass.

Abstract:In order to research the energy dissipation law and damage morphology characteristics of granite with different burial depths under low-temperature freezing and expansion conditions under impact dynamic loading. SHPB test system was used to carry out impact dynamic load test on granite with different burial depths at 0, -10 and -20℃, and the effects of temperature and burial depth on energy dissipation and damage morphology of rock were analyzed. The results show that: with the decrease of temperature, the dissipated energy and absorbed energy per unit volume of granite specimens show a tendency of increasing and then decreasing, and the dissipated energy and absorbed energy per unit volume of granite show a tendency of decreasing and then increasing with the increase of burying depth; and the crushing degree of rock shows a tendency of decreasing and then increasing with the decrease of temperature.

Abstract:Due to the surface resources of an iron ore mine in Anhui Province are exhausted, to carry out the work in the open pit, the choice of mining methods and mining program to determine the key to off-production to achieve production, this paper addresses the issue, according to the actual geological situation of the mine, and reference to the many factors affecting the choice of mining methods, the initial and preferred choice of mining methods, so as to design a reasonable mining program, the study showed that the tentative use of the upward horizontal stratified approach to the road to fill method as a mining method, this mining method selection for the mine to achieve safe and efficient production of theoretical basis, has practical significance. After the study, it is shown that the upward horizontal stratified approach filling method is tentatively adopted as the mining method, and the selection of this mining method provides a theoretical basis for the mine to achieve safe and efficient production and has significance for practical application.

Abstract:Taking a copper-nickel ore in Xinjiang as a research object, in response to the serious impact of direct reuse of flotation reture water from copper nickel ore on the effective recovery of copper and nickel, this article investigates the effect of adjusters on the effective recovery of copper and nickel by eliminating flotation return water. Under 100% return water conditions, adopting the bulk flotation process of two roughing-three scavenging-three cleaning to obtain copper nickel mixed concentrate, the mixed concentrate uses activated carbon and lime as adjusters. Adopting a copper nickel separation process of one roughing-two scavenging-two cleaning, a nickel concentrate with nickel grade of 9.78% and recovery rate of 74.23%, a copper concentrate with copper grade of 21.09% and recovery rate of 78.64%, can be obtained. This study can better solve the problem of deteriorating effectively recovering copper and nickel in flotation return water reuse, improve the recovery rate of copper and nickel, and provide important technical support for the reuse of flotation return water in similar copper and nickel mines.

Abstract:This research deeply focuses on the Kamoa-Kakula copper mine in the Democratic Republic of the Congo, and conducts a comprehensive analysis of its beneficiation process, covering key elements such as the properties of the raw ore, the design flow, the design indicators, and the crushing and grinding process flow. Moreover, it elaborates in detail on the innovative EPCM management strategies. Through a systematic analysis of the project, it fully demonstrates the crucial effectiveness of high-quality design and innovative management in the success process of the project, aiming to provide a highly valuable reference example for similar mining projects.

Abstract:Safety management is an indispensable and important part in the construction projects. In order to solve the problems of inadequate safety management system and low management efficiency in current construction projects, this paper systematically analyzes and compares safety management based on the construction safety management practice of Kamoa project in The Democratic Republic of Congo, and provides reference for similar mine concentrator construction projects. Through analysis and comparison, the formation of collective safety awareness, conduct of safety education and training, development of safety system and implementation of innovative safety management concept is more conductive to safety management.