Advanced Materials Research Vols. 734-737

Abstract: The characteristics of structural plane are very important to the stability of rock mass.In this paper,the stress and deformation characteristics of structural plane under direct shear conditions are analyzed based on FLAC3D code.And the influence of structural plane inhomogeneity to shear test was discussed.The results obtained in this paper indicate that, with the increase of normal stress, the shear strength of structural plane is constantly increasing,and the tow of them presents linear feature significantly. The normal displacement and shear displacement increase with the rise of the normal stress too. The peak shear strength increases gradually on the condition of uneven friction angle in the interface. This situation changes smaller when the discrete degree of friction angle is small. The peak shear strength increases significantly when the discrete degree of friction angle is big,and the stress-displacement curve exhibits a nonlinear characteristics before yield.

Abstract: According to characteristics of air curtain obstructing airflow in mine tunnel, utilized turbulent flow dynamic viscosity method, and three-dimensional steady-state incompressible Navier-Stokes equations of computational fluid mechanics, the simulation of flow field in mine tunnel was made by changing outlet parameters of air curtain. The results show that the obstructing airflow capability increase with the increase of the outlet airflow velocity, the obstructing airflow capability decrease with the increase of the outlet width when the amount of wind is a certain value, the obstructing airflow capability increase at first, then decrease with the increase of the outlet angle. When the parameters are the same, the obstructing airflow capability of acyclic air curtain is better than that of circular air curtain.The result of simulation analysis of mine air curtain can be used as the basis for optimized design.

Abstract: Huolinguole lignite (HL) was oxidized with aqueous NaOCl solution under mild conditions. The oxidation products were analyzed by GC/MS. In total 111 products from the HL oxidation were detected, most of which were benzene polycarboxylic acids and short-chain alkanoic acids, while a predominant chlorinated compounds such as trichloromethane, dichloroacetic acid, trichloroacetic acid were also identified. These results indicate that oxidation of coals with aqueous NaOCl solution may be a promising method for high value-added utilization of coals.

Abstract: In order to predict mine gas drainage quantity for research purposes, using unbiased grey GM(1,1) model to replace the traditional GM(1,1) model, was obtained by fitting experimental mine gas drainage quantity change trend. Based on the application of dynamic Markov model prediction, and the prediction results and the real value of comparative analysis. The results show that, the dynamic unbiased grey Markov model for predicting mine gas drainage volume of high fitting precision, and results are correct and reliable, has great practicability and universality.

Abstract: Mine earthquake is one of induced earthquakes caused by mining activities. When strong mine earthquake happens, the propagation process of seismic waves have enormous energies, which will make dynamic load pulse impulsion for coal seams and roadways strongly, as the result, the coal would collapse and throw out coal-rock mass dynamically, moreover, it would evoke impulsion pressure which could cause casualties.

Abstract: Based on the dominant position of coal in the energy structure in our country, the paper analyzes the present situation that the recovery rate of coal resources in our country. From two aspects of natural factors and human factors, it analyzes the causes of low recovery rate of coal resources, and points out that human factors are the main reasons for the low recovery rate of coal resources. Finally, suggestions for the improvement of recovery rate of coal resources are given.

Abstract: the stabilization of the rock support structure is the key to the safety and stability in the deep soft rock roadway, According to the bearing characteristics of surrounding rock, this paper puts forward the definition of double bearing structure, using FLAC3D numerical simulation software and theory of mechanics analyses Bearing Mechanism of Double Support Structure. The research shows: Excavation of soft rock roadway, the vertical strain and horizontal strain of the surrounding rock of roadway has wave, the surround rock appearing obvious deformation and displacement of roadway roof and floor in 3M, and the roadside appearing extrusion failure in the range of 2m. The roadway is more stable as the figure of the plastic radius is smaller, the same to outer bearing structure’s boundary and the width of outer bearing structure and plastic zone.

Abstract: Zhundong area in Xinjiang Uygur Autonomous Regions, China is rich in subbituminous coal reserves. Zhundong coal is characteristic of low mining cost and fine reactivity. However, the serious slagging and fouling occurring on the heating surface because of the high sodium content of Zhundong coal leads to very dangerous and uneconomical operation of Zhundong coal-burning boilers. Here, A method using a washing solution to remove sodium from the coal is presented and the effects of temperature, pressure and washing solution amount on the sodium removal from Zhundong coal was investigated. The experimental results show that the temperature employed is the main influencing factor for sodium removal and pressure has little influence on the results. After treatment with the right processing conditions, the upgraded Zhundong coal with the sodium content below 2% (based on ash yield) is obtained and the sodium removal efficiency is higher than 70%.

Abstract: According to the existing equipment data of mining and transportation of Antaibao open-pit mine, this paper which uses different kinds of equipment as the research objects, carried out a detailed analysis of the required equipment models during crossing the anticline in the open-pit mine combining with practical and theoretical calculations on-site. This research not only confirms the type and quantity of dump trucks and other major equipment, but also provides guidance to the production for the mine.

Abstract: The geological conditions of haulage roadway of the working face 1528 in GeQuan Coal Mine, which belongs to the JiZhong Energy Group CO., Ltd., and the research findings of Key Stratum Theory was taken into consideration, based on which established a mechanical model could reflect the basic features of rock stratum and made a profound investigation on the form and conditions of the fractures on main roofs. A systematic study on the stress, deformation, and damage characters of fractures on main roofs beyond a retained entry has been made by the laboratory test. The experiment shows that the deeper the fracture is in the rib, the greater the differences between dimension of compression and deformation will likely be, and the greater the influences on the stability of surrounding rock will it has. At the same time, smaller is the overhanging beam in mined-out area, more beneficial to roadway maintenance. On a certain deformation of main roof, it creates subsidence that is great difference in different position of a roadway. The subsidence near those mined-out areas is much more than those near the ribs. The application of a strong and effective measure could help cut the roof out and assure its stability.