QUANTITATIVE ASSESSMENT OF IN-SITU STRESS IMPACTS ON ROCK MASS CAVABILITY IN BLOCK CAVING MINES

Abstract

Block caving is a large-scale mining method that has been favored due to its ability to achieve high productivity and low operating costs. Especially in recent years, when more lowgrade and large ore bodies are discovered, and its extraction is only economically feasible under the low-cost extraction method. Rock mass caving ability—the capacity of rock to propagate vertical failures—is primarily influenced by lithology, rock mass properties, and the hydraulic radius of the undercut level. However, recent studies on the effects of in-situ stress fields have presented conflicting views on the significance of stress evaluation in caving behavior. This study investigates the influence of in-situ stress fields using an advanced numerical modeling technique based on the finite element method (FEM). A model built on a real-world mine example was used to analyze the influence of the in-situ stress fields and stress ratios on the cavability of the block. Cave propagation and ore body failure mechanisms were examined under a broad range of varying stress conditions. Three distinct in-situ stress ratio (k) domains were identified, each exhibiting significantly different caving behaviors in terms of yielded rock and caved material. Additionally, stress redistribution patterns were analyzed with a focus on workplace stability, and recommendations for improving operational efficiency were provided.