Development of an Air Permeability Test Method and Application to Underground Mining

Potential problems associated with groundwater inflows are a major concern to many Saskatchewan mining operations. Rock mass behaviour and stability have been linked to groundwater inflow potential. An estimate of the hydraulic conductivity of the rock mass is an important factor for assessing groundwater inflow potential. This paper presents a procedure that was developed to conduct air permeability tests, for estimating the hydraulic conductivity of the rock mass. Tests were conducted near underground excavations with the goal of assessing links between measured air permeability, rock mass classification and the rock mass response to adjacent excavations. Measured changes in air permeability corresponding to the distance from excavation boundaries may indicate changes to joint properties such as joint aperture, continuity and frequency. This study outlines the instrumentation, the experimental and analytical procedures, and the preliminary results from testing.