Utilization of carbon dioxide during borehole underground coal gasification

Purpose. To develop an innovative approach for carbon dioxide utilization during the borehole underground gasification of coal at the SE “Lvivvuhillia”. Methods. The determination of stratification cavity parameters in the rock mass during underground coal gasification was based on analytical studies. These studies employed the method of stress-strain state calculation of rock layers implemented in the “GeoDynamics Lite” software. This method involves obtaining geometric and physical distribution parameters for characteristic rock layers from the coal seam to the surface. Input data for the research included data on the geological and mining conditions of coal seams and the technological parameters of the mining operations. Findings. Analysis of the rock layers’ geometric and physical load parameters confirmed the expansion of abnormal pressure zones in the rock mass. It was established that these parameters change from the coal seam to the surface, both toward the rock mass and in the direction of the gasified cavity as the combustion face advances. These dynamic changes in the roof structure promote the formation of stratification cavities, which can be used as localized sites for efficient carbon dioxide sequestration. Originality. The dependencies of changes in the dimensions of stratification cavities in the rocks of roof above an underground gasifier on the rate of combustible face advance have been established. Taking this dependency into account allows for predicting the degree of carbon dioxide utilization in technologically created cavities. Practical implications. For the Chervonohrad mine, the parameters of stratification cavities within the rock mass at seams n7n, n7 and n7v levels during the gasification of seam n7n were determined. These findings allow for the assessment of carbon dioxide utilization volumes in the future.