Development of a geomechanical model based on suitable estimations of GSI and UCS in mining production slopes at the TilTil district, central Chile

Abstract

The majority of applied geomechanical models are poorly suited for use in small-scale mining operations owing to the time, costs, and technical knowledge needed to usefully apply them. This means that it is often not possible to accurately obtain an adequate account of rock properties in advancing mining areas, which can lead to geomechanical related problems such as rockfalls and slope failures. Here we propose an adaptation to an existing methodology which allows the construction of a simple geomechanical model, that can be adjusted depending on mining developments, and used to develop recommendations for the design parameters of mining production slopes in small-scale open-pit operations. The adapted model, which considers the use of rock mechanics tests on rocks collected over a district level, along with UCS estimation, GSI characterization and FEM modelling, is based on an estimation of the parameters derived by1; namely material constants mi, mb, s, and a. Results show that the Uniaxial Compressive Strength (UCS), measured for rocks in the same district, serves as an adequate estimation of the specific UCS in the advancing mining area in the modified geomechanical model when both the field estimates and direct sampling are within a determined range.