Development of a geomechanical model for determination of elastic modulus and study on caving span induced by mechanized longwall mining

Abstract

A geomechanical model was developed to determine the elastic modulus, analyze rock and surface displacement, and study the caving span induced by mechanized longwall mining. The deformation and displacement of rock were examined, including stress distribution, development and height of the failure zone, caving span of the longwall, layer arrangement, deformation vectors, maximum subsidence, and boundary displacement angle. Rocdata software was used to determine the elastic modulus (E), cohesion (C), and internal friction angle (φ) as inputs for the model. RS2 (Phase 2) software from Rocscience Inc. (Canada) was applied to calculate displacement parameters. Results showed maximum subsidence of −2.250 m in the dip direction and −0.659 m in the strike direction. The boundary displacement angle was 47°, while the caving height was 10 m. Caving repeated at the 10th span, corresponding to a mined strike length of 65 m, after which the caving span and height of the caving zone repeated.