Stability analysis of crown pillar under the zone of relaxation around sub-level open stopes using numerical modelling

Abstract

The stability of stopes and pillars is a critical concern in deep underground metal mining due to the potential for stress concentration and relaxation that can cause the dynamic failure of pillars. This study employs a finite element approach to investigate the behaviour of crown pillars to various stress and geo-mining parameters. The analysis includes examining stresses, deformations, and yielding zones around the crown pillars using variations in rock mass parameters. The study involves 240 non-linear numerical models with the Mohr–Coulomb elastoplastic failure criteria under plane strain conditions. The results indicate that increasing the crown pillar thickness from 5 to 8 m reduces maximum vertical deformation by 55.8% and the maximum extent of yielding zones from 2.2 to 0 m. The study suggests a 6 m crown pillar for depths up to 670.56 m and thicker pillars of 7 m or more for greater depths.

Keywords:

• Numerical modelling
• crown pillar stability
• sub-level open stope
• zone of stress relaxation

Acknowledgements

The authors are thankful to the management of the mines, who provided the required data for the study. This study forms a part of the ongoing doctoral research of the first author. Assistance provided by the concerned personnel of various departments in IIT(ISM), Dhanbad, is highly acknowledged. Views expressed in this paper are those of the authors and not necessarily of the organization to which they belong.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Data availability statement

The datasets analysed during this study are available from the corresponding author upon reasonable request.

Additional information

Funding

This research has not received any funding from any source.