Advanced Materials Research Vols. 962-965

Abstract: Sandstone roof water is the direct water-filling resource of coal mining, which has a great effect on the mine production. However, because of the unequal enrichment of Sandstone roof water, it is difficult to prevent and treat sandstone roof water. In order to study the water enrichment of coal roof sandstone, take 8# coal seam of ZhangBei coal mine as an example. Based on the analysis of influencing factors and the establishment of evaluation index system of the enrichment of sandstone roof water, water enrichment of coal roof sandstone was predicted by the use of GRNN. Researches have shown that the influencing factors of water enrichment of roof sandstone include sandstone thickness, mudstone thickness, fracture strength and fracture density. The prediction model of water enrichment of coal roof sandstone based on GRNN has the good ability of prediction and generalization, and the predicted results can provide certain basis for water prevention and treatment of sandstone roof water.

Abstract: The interaction relationship between support setting load and surrounding rock is the basis of support selection and surrounding rock control. The paper analyzes the interaction relationship between support setting load and surrounding rock by means of theory and experimental data. It is proved that setting load has an important influence on inhibiting immediate roof caving and enhancing immediate roof strength. The increment of setting load can prevent immediate roof falling. Setting load can affect the supporting body stiffness and distribution range of augmented resistance .The lower of the setting load, the larger of the roof deflection. The paper puts forward calculation method and influencing factors of coal wall stability ratio. According to the pressure date comparison of Tiebei mine two coal faces, setting load is one of important factors inducing roof large area weighting.

Abstract: Recovery room could ensure the returning safety of working face equipment, improve mining and moving speed efficiency. Surrounding rock of working face will be distributed after recovery room driving, surrounding rock convergence drastically, and mining influence surrounding rock of recovery room also. Stress distribution around recovery room complex. Surrounding rock deformation rule along tendency of working face was studied by filed measurement in Sihe cola mine of the Jincheng coal district in China. It reveals surrounding rock deformation mechanics during coal pillar of working face through.

Abstract: The test method of shallow plate load was used in the bearing capacity of foundation of Yushu City , doing two groups of loading test in different depths and doing survey and comparative test between test point nearby and sites in the same horizon.It gets the law of foundation soil bearing capacity value got by different test methods and provides the basis for Jilin Province to establish the local standards through the comparison of load test and geotechnical test , static cone penetration test and standard penetration test.

Abstract: Evaluation possibility of low grade manganese mineral from Hunan by froth flotation technique was investigated. Manganese mineral sample was characterized with mineralogical analysis, XRD, and SEM studies for its mineral content and surface characteristics. XRD analysis showed that the gangue contents of manganese minerals are constituted mainly by dolomite as a carbonate mineral, quartz and feldspar. SEM indicated that existence of rhodochrosite, which mainly fills in the dolomite minerals. The influences of important factors on manganese mineral flotation are investigated. The size of grind, pulp pH, dosages of depressant and collector are essential to the effective recovery of rhodochrosite in manganese mineral flotation.

Abstract: According to the huge losses of people’s life and property caused by coal rockburst, we make numberical simulational research on coal deep buried roadway fault rock burst which is based on the related fators about the occurrence of fault rockburst. Simulation results show that,the stress in fault is the most significant,and with its continuously accumulation ,if it is up to the ultimate strength of coal and rock mass,which will occurre rib spalling, and even it will bring the accumulated elastic energy out ,then induced by fault rockburst. So simulation results are of guiding significance to the occurrence mechanism and predict of coal roadway fault rockburst.

Abstract: Based on the uncertainty measurement theory and entropy weight method, the classification model for rock burst tendency of coal was established. Four indexes were selected as evaluation indexes, i.e., the dynamic failure time (DT), the elastic energy index (W_ET), the impact energy index (K_E) and the uniaxial compressive strength (R_C).The weight coefficients of above four evaluation indexes were calculated by the entropy theory. Finally, the model of rock burst tendency classification based on the uncertainty measurement theory was applied to the classification of five different coal samples. Compared with the comprehensive evaluation method and fuzzy comprehensive method, the results show that the uncertainty measurement model has excellent performance and high accuracy prediction, which proves that this method used to classify the rock burst tendency of coal is reasonable and effective.

Abstract: Bad and asymmetrical deformation occurred in soft tilted strata roadway for the existence of tectonic stress, we carried out the study on geostatic stress character and optimizing bolting support parameters in 2# coalbed of Zijin Colliery. Based on original rock stress measurement, broken rock zone measurement and survey of roadway deformation, characters of original rock stress and range of broken rock zone were given. According to existent problems, a variety of numerical computations were carried out by FLAC3D, failure mechanism of roof is shear-tensile failure. New support methods of bolt installed vertically in tilted roof and strengthening support of sidewalls and corners of roadway are figured out. The research was carried out for 600 meters. The monitoring results prove that the optimized support design is viable and the new bolting parameters are reasonable.

Abstract: The natural slope in the process of excavation, due to the dynamic action of blasting damage the integrity of the original rock, the slope rock mass occurred the partial or whole layer crack and the formation of slope rock mass loose zone, caused the strength of rock mass damage problem, and even lead to landslide. Aiming at the problem of the dynamic influence of blasting on the slope rockmass, study on the algorithm of the blasting damage in this article, combined with the Xiaolongtan coal mine slope engineering as an example to verified the damage model, the results showed that the damage model calculation value and the damage zone measured results have good consistency.

Abstract: The flotation methods of scheelite, such as conventional flotation, heating flotation, lime flotation and their application were reviewed in this paper.