Review of the relation between pillar load and opening convergence in pillar design using the ground reaction curve concept

Current research indicates that underground stability is a function of more than just pillar strength and tributary area loading. From pillar observations and numerical modeling results, one finds that stress interactions between the pillars and the surrounding rock mass can impact mine stability. Therefore, the underground pillar design methodology may benefit from reevaluating the loading conditions of pillar systems. Thus, pillar stability calculations may be able to better account for the behavior of non-homogenous rock as well as stress interactions between different stratigraphic layers within the immediate overburden rockmass. The Ground Reaction Curve (GRC) has been used as a means of correlating strata displacements to stress conditions. In addition, the Support Reaction Curve (SRC) has been used in modeling the response of a support system under load, as a function of support properties and installation time with respect to opening development. In comparing the GRCs and the SRCs for different support systems, one can evaluate the effectiveness of installed support system in maintaining the integrity of the excavated area(s). This paper presents a preliminary investigation into the utilization of the GRC and SRC for the design of mine pillar support systems with respect to anticipated pillar loading and opening convergence.