The complex geological and hydrogological conditions under the unconsolidated and confined aquifer in the Qidong coal mine have resulted in serious water-inrush hazards. Multi-information superposition was used to predict water inrush areas. Six controlling factors (the specific yield, the effective thickness and load transfer coefficient of the aquifer, the fractal dimensional value of bedrock faults, the effective thickness of the protective bedrock layer, and the distance between the key hard stratum and the primary mineable coal seam) were selected, and a multi-information superposition model was established. Relatively safe areas and medium and higher risk areas were identified using a geographic information system (GIS) and the analytic hierarchy process (AHP). Using the no. 71 primary coal seam in the northern portion of the Qidong mine as an example, the water-inrush areas predicted by the model aligned with observed conditions, which validates the multi-information superposition model. Potential inrush areas of the no. 61, 82, and 9 primary coal seams in the southern portion of the Qidong mine were subsequently identified using this method, which will aid future mining operation. 相似文献
Reproducible buckled and porous sub-micron diameter polycaprolactone (PCL) fibers were produced by simple electrospinning process for biomedical applications. In this study, six types of solvent combinations with different vapor pressures were used to study the effect of phase separation on the morphology of electrospun fibers. The fiber morphology, Infrared spectroscopy, water contact angle and tensile test were performed to study the material properties. It is evident that the fiber morphology was affected by solvent combinations used for the fabrication of sub-micron fibers. The solution viscosity, the collecting distance and the type of solvent combination used could be an optimum parameter for the generation of porous-buckled fibers with narrow pore size distribution. The simplicity of the set-up is the immense advantage for producing buckled and porous elastomeric fibers for tissue engineering applications. All the fibers were spun on a motionless collector plate to study the properties of fibers. The combination of surface pores with the buckled pattern could be of great importance in the field of biomedical engineering. 相似文献
Coal mining can dramatically change hydrogeological conditions and induce serious environmental problems. Fifty groundwater samples were collected from the main aquifers in the Yuaner coal mine (Anhui Province, China). The results show that the main hydrogeochemical processes in the mine include dissolution, precipitation, pyrite oxidation, desulfurization, and cation exchange. The Neogene porous aquifer is affected by groundwater flow conditions; its main hydrogeochemical processes are dissolution of carbonate minerals and gypsum, and cation exchange. The Permian coal measure’s fractured sandstone aquifer was confirmed to be controlled by the region’s geological structure; its main hydrogeochemical processes are desulfurization and cation exchange. The Carboniferous Taiyuan limestone aquifer was determined by both groundwater flow conditions and regional geological structure; its main hydrogeochemical processes are dissolution of carbonate minerals and gypsum, pyrite oxidation, and cation exchange. Additionally, hydrogeochemical inverse modeling of the groundwater flow path confirm the hydrochemistry results and principal component analysis.
We examined the primary mechanisms controlling water quality evolution in the Carboniferous aquifer in the Yangzhuang coal mine (Huaibei coalfield). Q-mode factor analysis explained how the Na+ and SO42? concentrations gradually increase and the hydrochemical type transforms from Ca-HCO3 to Ca·Na-HCO3 and Ca·Na-HCO3·SO4 along the flow path. The high bicarbonate concentration appears to be due to dissolution of calcite and dolomite and an open carbonate system, while frequent water inrushes and the declining water level provide evidence for the relative closure of the Carboniferous limestone aquifer. Gypsum dissolution is the main SO42? source. Inverse geochemical modeling sufficiently explained the hydrogeochemical processes that control the water quality evolution. These findings should aid the interpretation of groundwater hydrochemical evolution and groundwater quality management in the study area and other north China coalfields.