Analysis of influence of types of rocks forming the goaf with caving on the physical parameters of air stream flowing through these gob and adjacent headings

In the paper there are presented results of influence of types of rocks forming the goaf with caving on the physical parameters of air stream flowing through these goaf and adjacent headings. It was assumed. that goaf with caving are porous medium. which permeability and porosity depends on the distance from the front longwall and from stratification resistance of rocks forming the heap. On the base of stand tests values of stratification resistance of rock littering at the roof of tested longwalls were determined. The main aim of the tests was to determine an impact of type of rock littering in mined seam on values and distribution of velocity and pressure of air stream in the gobs This aim was realized by a determination of value of stratification resistance of roof rocks on the tested parameters of air stream flowing through these gob. Analysis was performed in the ANSYS Fluent software. Modeling studies were performed for real exploitation longwall and additionally for two types of roof created with the most often presented rocks. For each of these systems distributions of velocities and static pressure along assumed measurement lines were determined. Analysis included determination of physical parameters of the air stream flowing through the gob for real exploitation conditions of this longwall and additionally for assumed two (the most often presented in reality) variants of rock presented in the roof of mining longwall. Developed research methodology and obtained results should be use during selection of ventilation parameters and preventive actions connected with reduce methane and fire hazard in underground mining.