Recognition of properties of the rock mass surrounding a mineral deposit is particularly important for the mining operations at greater depths. Since the rock mass is usually not homogeneous, and its parameters have characteristics of randomness, underground workings safety issue should always be analysed taking into account the dispersion of the values of these parameters around their mean values. In order to assess the impact of geotechnical parameters uncertainty on the excavation stability one uses the appropriate statistical approach. In this paper, by analysing successive combinations of geomechanical parameters of the rock in the measured range, we examined the effect of their variability on risk of underground excavation instability using response surface method.
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