Developing coal pillar stability chart using logistic regression

Abstract

Logistic regression was utilised to calculate the probability that a particular pillar of a given geometry (width to height ratio) and a known stress condition (strength to stress ratio) will be stable. The stable-failure boundary was also determined. The logistic regression was also used to calculate and draw isoprobability contours. These contours represent the probability of stability of coal pillars based on the probability function for each stability class and are a valuable design tool in quantifying the instability probability of coal pillars.