Analysis of the Vertical Movement of Crown Pillar in Cut and Fill Mining Using Finite Element Method
Keywords:Geo-Mining Parameters, Crown Pillar, Numerical Modelling, Vertical Displacement, FEM, Orebody Width, Pillar Depth.
Crown pillar is a horizontal pillar left to protect the upper level workings when stope advances along the up dip direction and approaches to the upper level in cut and fill method of mining. These horizontal pillars are the main support structures for stopes during excavation. In this study the vertical movement of the pillars at crown level has been analysed by varying the rock mass parameters such as geological strength index (GSI), uniaxial compressive strength (UCS or ƒãci), modulus of elasticity (E), depth of pillar from surface (D) and thickness of horizontal pillar (T) using finite element method.These analyses have been conducted based on 135 non-linear numerical models considering Drucker-Prager failure criterion in plane strain condition. Results of finite element models are represented in terms of displacements in rock mass of the pillars. Displacement profiles of rock mass along the predefined paths are obtained, presented and analyzed for different models having variation in geo-mining conditions. Finally, the most important parameters affecting the convergence significantly are identified which may be incorporated in the design of the optimum crown pillar thickness.
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