Determination Method of Gas Content in Limestone and Its Application

Abstract

The determination of gas content in coal and rock mass is the basic work to predict the gas emission of working face and mine. Generally speaking, gas exists in coal body in adsorbed state and free state, and the amount of adsorbed gas accounts for a large proportion. In order to explore the gas occurrence of lime rock mass, isothermal adsorption experiments are carried out on K2 and K3 limestone in Yangquan mining area. The experiments show that the gas adsorption capacity of lime rock mass is very small and mainly exists in the rock mass as free gas. When the temperature is constant, the gas content of limestone rock mass is linearly related to gas pressure and pore volume. That is, gas pressure and pore volume are the main factors determining the gas content of lime rock mass. Based on the gas state equation, this paper studies and determines the indirect calculation method of gas content in lime rock mass. The indirect calculation method is used to predict the gas emission of z15104 working face in Sijiazhuang coal mine. The prediction accuracy is about 86%, and a good prediction accuracy is obtained. It has certain guiding significance for mines with similar geological conditions.