Advanced Materials Research Vols. 616-618

Abstract: Study on the inorganic inhibitor on jamesonite and marmatite separation flotation，the result indicate the inhibition of minerals mainly has three forms. They are respectively: Inhibitor adsorbed on mineral surface to generate new chemical film which didn’t reaction with collector；After the adsorption of depressant, the reaction between depressant and the adsorbed collector molecule will occur on the mineral surface, which result in the ineffectiveness of the collector；Inhibitors and collector competitive to adsorb on mineral surface, and then the collector is pushed to the liquid phase.。The inhibitor’s performances are relevant to its oxidation and chemical property.

Abstract: Air leakage of the main air doors in the mine deteriorates the underground working environment and threatens both the safety production and the physical and mental health of workers. Based on the complex air-leaking problems of the main air doors, this paper has worked out a method by combining SF6 tracer technique and pressure energy test together. In this way, the air leakage law of the main air doors between the intake and the return airway of SHAOYAO coal mine has been determined: the total air leakage of the 10 sets of main air doors amounts to 499. 33m3/min; the amount of air leakage has positive correlation with the differential pressure of air leakage; on the basis of the law of air leakage resistance, the windage resistance of the main air doors has been calculated. According to the air leakage features of the main air doors, this paper also puts forward the control technology, such as spraying polyurethane foam, keeping the tightness of doorframe, etc. After field application, the amount of air leakage has decreased 56.1% on average. And accordingly, the air leakage of the main air doors has been effectively controlled and the underground working environment has been greatly improved.

Abstract: The stability of roadway is subject to a variety of conditions, including geological conditions, and other natural factors can not be changed, it must be through supporting the roadway stability. At present the design of supporting parameters in the gateway have many methods, but there are some shortcomings. This paper used non-linear FEM to optimize the supporting parameters. The coal roadway minimum failure zone within surround rock has been set as objective function. The results show that: The support parameters and the failure zone within surround rock exist optimal relations, which can be used as a method of supporting design parameter.

Abstract: CO₂ enhanced CBM recovery(CO₂-ECBM) is an important way for reducing CO₂ emission into atmosphere and enhancing coal-bed methane (CBM) recovery. The interaction between supercritical CO₂ and coal petrography has been investigated since the 1990s. Advances in the interaction between supercritical CO₂ and coal petrography are reviewed in light of certain aspects, such as the competitive multi-component gas adsorption, sorption-induced coal swelling/shrinkage and the fluid-solid coupling between fluids(such as gas, liquid and supercritical fluid) and coal petrography. It is suggested that a comprehensive feasibility demonstration is necessary for a successful application of the technology for CO₂-ECBM. At the same time, it also indicated that there are some questions must be discussed in future, such as the influences on pore structure, coal adsorptivity and permeability of the reaction of ScCO₂-H₂O and rock and small organic matters are extracted by supercritical CO₂.

Abstract: Along with the rapid increase of energy consumption of China, more attention has been paid to the CBM as one kind of clean and high-quality energy. CBM is the greatest threat to the coal mining. If CBM is extracted and well used before coal mining, the environment will be improved and gas explosion accident in coal mine will be obviously diminished. The exploit and advantage of CBM improves the coal field exploration degree and coal mine production safety and efficiency.

Abstract: According to the occurrence condition of one mine’s primary face coal seam and using the methods of theoretical calculation and numerical analysis, this paper determined the reasonable parameters of the high-water material filling body and made an industrial test in the field haulage entry. The results showed that the parameters of the filling body were reasonable and the filling body can maintain the roof of the entry effectively and obtain good supporting results.

Abstract: In order to minimize the threat of ground pressure disasters, this paper introduces the work of microseismic monitoring based on analyzing a large range of mining condition of No.92 ore body of Tongkeng Tin Mine. A system of microseismic and ground pressure disaster monitoring in the range of No.92 ore body mining area is established by using three 12-channel of rock accoustic emission equipments and a 24-channel microseismic monitoring system, combined with ordinary surrounding rock pressure and displacement monitoring instruments. Data acquisition, analysis and treatment are automatically. Field application shows that many ground pressure activities are monitored effectively by analyzing the rock acoustic emission at different energy and the moving law of overlying strata. The technology provides a reliable support to early warning and control of ground pressure disasters.

Abstract: Based on the precast pile foundation field test of the power plant, the distribution and dissipation of the excess pore water pressure induced by the construction of the precast pile are first analyzed after the plastic drain board driven in the soft ground. Then the influence factors of the distribution and dissipation of the excess pore water pressure are presented. Subsequently the quality problem of the pre-date driven pile caused by the construction of the precast pile is studied. The main control parameters of the precast pile construction under the complicated condition are provided, which will provide a reference for such similar projects.

Abstract: With the purpose of finding effective method in construction schemes decision-making and improving productivity level of construction enterprises, the application of simplified ELECTRE method in optimal selection of construction schemes was studied in this paper. The calculation process and main steps of simplified ELECTRE for optimal selection of construction schemes were presented here. An example of construction scheme optimal selection for shear wall template was analyzed, and the calculation progress was programmed on the platform of MATLAB 7.0. The result analysis shows that simplified ELECTRE can supply satisfactory preferential order of alternatives considering comprehensive influence of many factors. It has simple and clear sorting principle, furthermore, it is very suitable to be calculated in program, and the result is accurate and reliable. Simplified ELECTRE method is proved to be good to solve the problem of optimal selection of construction schemes.

Abstract: By using the self-developed meso shear test equipment for coal or rock containing gas, non-restrictive direct shear tests under the gas pressure of 0 MPa, 0.5 MPa, 1.0 MPa and 2.0 MPa were carried out. Based on the shear stress-shear stain curves and the meso-evolution laws of the shear fracture cracks, Fracture characteristics of the raw coal containing gas under shear loading was analyzed. The results show that: i) the gas pressure can hasten the growth rate of the fractural crack in raw coal containing gas, and accelerate its shear fracture process; ii) the shear fracture process of the raw coal containing gas experiences five stages; iii) the shear breaking process of coal results in two cracks: shear crack and tensile crack, and the cracks first appeared in the shear plane at both ends, then extension to the central until shear fracture surface formed.