Advanced Materials Research Vols. 734-737

Abstract: The soft rock stratum, possessing the characteristics of poor anchorage and large deformation, is frequently encountered in underground coal excavation where stability of the whole mining structure is always affected by the soft rock. Therefore, the bolt-grouting support technology in pursuit of an effective way for stability control of soft rock chamber of coal mine in china is conducted. Meanwhile, strata behaviors monitoring is carried out in the chamber to verify effect of bolt-grouting support. The results demonstrate that bolt-grouting goes well in soft rock chamber support.

Abstract: The graphite reserves are 1146452300 tons in Heilongjiang Province, and its industry technology development reflect three aspects: graphite mining and selecting technology, processing technology, tailings utilization technology. The existing problems of graphite industry in Heilongjiang Province are: non-standard mining and management, small and scattered enterprise scale, backward technology, short deep processing industry chain, the lack of skilled personnel. Strategies of graphite industry development include: scientific planning, government guiding and investment, the adjustment of product structure, the proportion improvement of deep processing products.

Abstract: Similarities and differences of overlying strata movement rule and abutment pressure distribution between filling stope and traditional strope was analysied guided by “practical mine pressure control theory ”. The admissible condition of strata’s depending from bending failure to caving was put forward, and caving zone’s height was analysied on the basis of this. Results showed that caving zone’s height and resistant force required by hydraulic pillar would decrease leapingly ,until the lowest strata transfer into the main roof, and when pressure was stable main roof’s maximum subsidence would become smaller. With the increase of the effective filling rate, filling body’s supporting degree to overlying would increase, when the filling rate reaches to a value, Coal wall’s edge would not appear the plastic zone, the abutment pressure curve is monotone decline with the peak near coal wall edge .

Abstract: According to the mechanical properties of paste filling body under special environment such as high temperature high humidity high stress and high airtight) in gob, mechanical properties of gangue-paste filling body was studied with the method of field core and laboratory test. The complete stress-strain curve of filling body under the condition of uniaxial and triaxial and the ultimate compressive strength under different confining pressure station were obtained through uniaxial and triaxial compression test. Six stages of uniaxial compression complete stress-strain curve (compression stage, elastic deformation stage, non-stable developing stages, plastic hardening stage, stress softening stage and residual deformation stage) were improved and developed. The deformation characteristics of filling body under triaxial compression were different from that under uniaxial compression. Namely the deformation of filling body under triaxial compression only appeared two deformation stages: linear deformation stage and plastic hardening stage, but had no softening stage basically under different confining pressures, which was benefit for controlling the ground subsidence and preventing the ground buildings.

Abstract: Acoustic emission (AE) phenomenon will occur during the production and propagation of internal cracks, and failure in brittle rock. Under uniaxial loading, the complete stress-strain curves and waveform data were obtained. The Welch spectrum estimation and Cubic spline interpolation method were used to analyze the evolution of F, R values (peak frequency, energy percentage) of AE. The results show that F-values are maintained at 100±20kHz, and the peak points of F and R above 25% which can be used as a precursor to rock failure that their waveform are burst-type. The combined analysis of stress and F, R supplies a more accurately method of predicting the occurrence of rock burst.

Abstract: Use a variety of coal analysis methods on the Wubu mining area main coal seams S1 and T1 in proximate analysis, elemental analysis, and technologic property analysis, the results show that the main coal seams is a kind of medium ash, medium volatile coal, especially low-medium sulfur, high calorific value coal. They have a good chemical properties and technologic properties, and can be used for coking, civilian, steam coal.

Abstract: Jixi mine area is one of the early mined areas in China and it's a typical deep mine. Because of large deformation of underground roadway and dynamic disasters occurred frequently in this mine, five measurement points of in-situ stress in this mine was measured and then analyzed with inversion. Based on these in-situ stress measurement data, numerical model of 3D in-situ stress back analysis was established. According to different stress fields, related analytical samples of neural network were given with FLAC program. Through the determination of hidden layers, hidden nodes and the setting of parameters, the network was optimized and trained. Then according to field measurement of in-situ stress, back analysis of initial stress field was conducted. Compared with field measurement, with accuracy requirement satisfied, it shows that the in-situ stress of rock mass obtained is basically reasonable. Meanwhile, it proves that the measurement of in-situ stress can provide deep mines with effective and rapid means, and also provide reliable data to optimization of deep roadway layout and supporting design.

Abstract: The complicated geological condition of the deep roadway is the important factors to influence the stability of the surrounding rock and the safety of mining. The rock specimen is taken from a coal mining of Jiangxi province. The chemical solution with different ion concentrations and PH value were prepared to simulate the complex environment of the deep roadway, and the specimens were immersed in the solution then carried out the axial compression test. The strength and other mechanical parameters of the specimen were obtained and the experimental results showed that the strength of the specimen being immersed all are lower than natural state. The reduced values become large with the immersed time and acid value increasing.

Abstract: In order to solve the problem of coal mining under villages of regions of Yaoqiao Mine, through comprehensive analysis, the author considers that strip mining has feasibility in realistic, meanwhile, a series of mining width and retaining width was studied for strip mining and eventually a mining project was put forward to meet the unique conditions. By comparing application conditions and range of application between continuous miner used in strip type of Wongawilli coal mining method and shortwall shearer mining method, the author analyzes the economic benefit and draws a conclusion that shortwall shearer mining method has better applicability. Those all provide a new way to mining under villages in Yaoqiao Mine and the conclusion can also be used for reference in similar mining conditions.

Abstract: The pressure control of soft-rock and roadway support has been one of the challenges of underground mines. Soft-rock support is very difficult in many places in China and is becoming a kind of main influencing factors in the development and economic of mining community. Numerical simulation research on the deformation mechanism of soft-rock tunnel contributes to the development of soft-rock support theory. The numerical calculation model of shallow buried soft-rock is based on Hongya coalmine; ANSYS is used to analysis the deformation law inward to find out how to control the soft-rock deformation. Hence we can know the main influence in the shallow soft-rock tunnel stability. The results are of great importance to the mines that have similar geological conditions.