Advanced Materials Research Vols. 1073-1076

Abstract: Mechanical and seepage characteristics of raw coal samples are the most important research contents of enhancing coal bed methane recovery, but the produce of raw coal sample is very difficult. Based on gas seepage instrument, mechanical and seepage characteristics were performed on normal briquette coal samples and coal samples containing gypsum. The results show that it can increase the cohesion and intensity level by adding gypsum in briquette coal. Porosity and permeability of coal containing gypsum is less than ordinary briquette coal sample. Permeability with axial strain curves of two kinds of coal samples can be fitted with a quadratic function well. In expansion stage, volumetric strain of ordinary coal sample is much smaller than the coal samples containing gypsum. The research has an important guiding significance on enhancing coal bed methane recovery and gateway supporting.

Abstract: In this study, the effects of important factors on malachite exploited from Tibet are investigated. Dosages of activating agents, depressants and collectors are essential to the effective recovery of copper in the flotation. The mixed collector ratio of SIBX: Armac C was varied as 0:1, 1:1, 1:2, 1:3, and 1:4. This investigation showed that using Armac C in conjunction with traditional SIBX collectors can successfully simultaneously recover copper oxides by flotation. The rougher scavenger copper recovery was as high as 85.2%.

Abstract: A surface properties of a sulfobetaine–type zwitterionic gemini surfactant with the structure of 1,2-bis [N-methyl-N-(3-sulfopropyl) -dodecylammonium] ethane betaine (ZGS12), were investigated in aqueous solution . The critical micelle concentration (CMC) of the gemini surfactant at different temperatures and mixed micelle properties of ZGS12 and sodium dodecyl benzene sulfonate (SDBS) were investigated. The results show that cmc of the gemini surfactant (ZGS12) decreases with raising temperature, Gibbs free energy changes and entropy changes are negative and postive, respectively, indicating the formation of micelle is spontaneous and driven mainly by entropy. According to the theory of regular solution , interaction parameters between the zwitterionic gemini surfactant ZGS12 and the anionic surfactant SDBS indicate strong attractive interaction and great degree of synergism in micelle formation due to weakening of the electrostatic head group repulsion.

Abstract: The F₂ fault Guo in Tianyu Coal Mine belongs to the oversize normal fault, and mining deep coal seam has an influence on the floor water-inrush. Therefore, study the reasonable width of the fault protected coal pillar is a great significance for the mine safety production. With different advance distances of coal face into the fault hangingwall, the authors, by FLAC numerical calculation, studied the characteristics of plastic zone and stress field in front of the coal face. The results show that influence zone scope of moving abutment pressure is about 70~ 80m. The fault is still in the pressure-relief area when it is in the moving abutment pressure zone. The conclusion is conducive to the stability of F₂ fault Guo, to prevent the floor from water-inrush, when the reasonable coal pillar width of the fault is wider than 80m.

Abstract: Through on-site inspection for the typical coal mines of each coal tectonic units in Southwest Guizhou as well as analysis of gas parameter, highlight information and gas control technology, the thesis makes the following conclusions. Namely, the overall state of coal seam gas occurrence in Southwest Guizhou mining area presents characteristics with high degree in north and west together with low degree in east. With regard to the existing problems in gas control of this region, it has put forward some suggestions. For example, people shall add test parameters for coal seam gas in most mines, find out status of the mine gas occurrence, make specialized design in terms of gas emission characteristics and perform strict management to ensure proper implementation. Moreover, people can carry out targeted research for outburst prevention indicator, establish suitable predictor system, optimize instrument and equipment, match with current advanced production technology, introduce professional talents and strengthen training for related technology and management personnel.

Abstract: The engineering background of this paper is located in the southern air return roadway of Tangkou Coal Mine. As a result of its characteristics such as deep buried depth, high ground pressure and enormous over-break, when drilling and blasting tunnels, fine management and control of blasting can be used to solve the problem of deep soft rock tunnel blasting precise molding and separated roadway. Field test procedures showed that compared with the original plan, this program can improve 38% of circulation footage, reducing the 50% of amount over-break of roadway,25% of cost savings, which achieved good technical and economic effects.

Abstract: In the process of open-pit mine stripping,the surface and slop that influenced by open-pit mining stripping, rock mass structure and lithology, blasting vibration, slope angle, groundwater and precipitation start to move and deform,which threatens the safe use of industrial and civil buildings adjacent to the open pit mining .In this paper, through the establishment of increasing the momentum of adaptive BP neural network,with the aid of existing sample data,we carried out on the network training, testing, and compared with the target, its precision is higher.The result showed that network is effective and reliable,and the trained network is applied to the observation point prediction,so we get the value of its settlement deformation in 2013.The method is expected to have the important meaning on the multi-factor coupling surface subsidence .

Abstract: Based on the prototype of No. 2307 filling working face in Yuyang mine, using the method of similar simulation combined with numerical simulation, the geological mechanics model is established to simulate and analyze the mechanics evolution law and the deformation and movement process of the surrounding rock and the surface during the filling mining. Research shows that backfilling can effectively control surrounding rock failure and the surface deformation, and the roof doesn’t collapse, but the bed separated fissures appear, and the maximum stagnation lags the working face by 58.5m; in the mining, surrounding rock stress releases and roof stretches, and the stress concentration appears in the front and end of the goaf, which is 1.47~1.78 times larger than that before mining, and the periodic weighting of filling working face is not obvious; the subsidence value is 212.7 mm after excavation, with the factor 0.06, and the ground level deformation and slope deformation shape are similar to the curve shape of roof caving control method with small values. The results have important theoretical guiding significance for controlling surface movement deformation in actual filling mining.

Abstract: The fracture system plays a very important role in the coalbed methane migration because they dominate the coal reservoir fluid flow. For this reason, determination of fracture permeability properties control mechanism for forecasting capacity is very important. This thesis fracture morphology of the role of coal-bed methane migration control, in single-phase flow conditions to simulate the fluid nature of the gas, the deduction of the macroscopic permeability, numerical calculations of the impact fracture surface morphology of permeability.

Abstract: The paper analyses problems of a lead-zinc ore from Yunnan with a sink and float test. In the paper, we explored the possibility of pre-discarding about the ore by dense-media process. Dense liquids with the specific gravity of 2.6, 2.7 and 2.8 were used in the test, respectively. -12mm crudes were taken into the test. Finally, it revealed that pre-discarding by dense-media separation can be used in the ore. 2.7 was taken as the best specific gravity of separation. 12~1mm was used as the optimal fraction of pre-discarding by dense-media separation. Pre-discarding rate was 45.53%. The light product with a lead grade of 0.29% and a lead recovery of 4.29% was pre-discarded in which the grade and recovery of zinc were 0.22 and 5.84, respectively.