Key Technique of Gas Sucking of "Three-Soft" Coal Bed and Its Application
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Forecast of Geological Gas Hazards for “Three-Soft” Coal Seams in Gliding Structural Areas
Abstract Gas outbursts from “three-soft” coal seams (soft roof, soft floor and soft coal) constitute a very serious problem in the Ludian gliding structure area in western Henan. By means of theories and methods of gas geology, structural geology, coal petrology and rock tests, we have discussed the effect of control of several physical properties of soft roof on gas preservation and proposed a new method of forecasting gas geological hazards under open structural conditions. The result shows that the areas with type III or IV soft roofs are the most dangerous areas where gas outburst most likely can take place. Therefore, countermeasures should be taken in these areas to prevent gas outbursts.
Research on coal structure indices to coal and gas outbursts in Pingdingshan Mine Area,China
According to the feature that coal and gas outbursts is controlled by coal structure in Pingdingshan mine area, based on the study of the distribution law of disturbed coal in Mine Area and the macroscopic characteristics of coal structure, the characteristics and genesis to micro-pore of disturbed coal, the relationship between the type of coal structure and gas parameter, and the structural feature of coal at outbursts sites are mainly explored in this paper. Further, the steps and methods are put forward that coal structure indices applied to forecast coal and gas outbursts.