A coupled empirical-numerical method for open-stope stability analysis considering stope dimensions

Most of the empirical methods are used for analyzing the stability of open stopes in underground mining and share common features based on two main factors: the interplay between geomechanical (mechanical characteristics) and geometrical (shapes and dimensions) parameters of the rock and orebody. The width of stopes is somewhat controllable, given the consistent strength and mechanical properties of the ore and its country rock. The dimensions of stable stopes are estimated using the "hydraulic radius" and "radius factor", which are the primary geometric factors after considering uncontrollable factors, such as the mechanical behavior of the ore and its country rock, environmental measures, safety, and the overall height of the orebody. Essentially, the influence of the stope's geometry, particularly its width, is equivalent to that of all other uncontrollable factors for a specific ore deposit. The hydraulic radius is inherently two-dimensional, leading to the consideration of only the length and height of the stope in its safe design. However, this approach overlooks the smallest dimension (third dimension), typically the thickness of the ore vein, despite evidence from observations and empirical studies indicating that all three dimensions of mining stopes can influence their stability during the ore extraction period. To address the neglecting of the third dimension in evaluating open stope stability, this article presents numerical models of various stopes with similar geomechanical characteristics but differing dimensions, analyzed using an explicit finite difference approach. The results are then assessed to understand how the third dimension impacts the hydraulic radius and, consequently, the stability conditions of the open stopes. Ultimately, a new mean modified hydraulic radius (MHR) is introduced to assess the influence of the ore body thickness on the stability analysis of open stope mines.

کلیدواژه ها:

Open stopes ، Numerical & empirical methods ، Stope width ، stability analysis ، Hydraulic radius