Evaluation of operating conditions of filtration columns of relief wells sited within the »Żelazny Most« mining waste disposal facility

Abstract

Regardless of geological conditions, the drilling of deep wells always disturbs the original state of tension in the drilled rock mass. In the course of drilling, the stability of the borehole wall is maintained by the drilling mud, and afterwards by the installed casing or filtration column, which usually are steel or plastic pipes with appropriately designed diameter and wall thickness. Casing columns in the wellbore should be sized so as to withstand the pressure of the rock mass without becoming deformed. Their strength parameters can be determined from the components of the primary state of stress in the rock mass and the magnitude of pressure occurring at the interface between the casing wall or filtration column wall, and the rock environment. In this paper, an analytical method based on the Coulomb–Mohr model was used to calculate rock mass pressures around the filtration column of relief wells situated in the slope of the »Żelazny Most« Mining Waste Disposal Facility (MWDF). Based on archival materials, a rock mass model was developed and was used for calculating undisturbed rock mass pressures at the filtration column wall and pressures coming from the gravel pack. The results obtained will be used for designing the filter pipe columns.