GAMAH-R: a new mining rock slope classification system

This article aims to present GAMAH-R as a new mining rock slope classification system, which was applied on three iron mines located in the western Quadrilátero Ferrífero, Brazil. This system allows to determine the slope performance concerning drainage, geometry and deformation aspects based on visual inspection, using a classification chart. Additionally, it was possible to represent all slopes evaluated on a GAMAH-R Map, providing guidance, not only for monitoring, but also to assessment of slopes performance. The performance map of mine A, a hillside mine, shows that predominate T4 slopes, mainly due to erosive processes caused by inefficient drainage system. Mine B, a deep open pit, shows that the slopes belong to classes T5, T4, T3 and T2, due to the failure mechanisms. The mine C, due to some final pit slopes with geometry according to geotechnical sectorization and maintenance drainage system, indicates a predominance of slopes of class T2. Herein, a new methodological failure susceptibility slope analysis correlating the Global Slope Performance Index (GSPI) and GAMAH-R is presented. This correlation, still under study and development in the Ph.D. thesis of the first author, allows to insert the studied slope in a matrix of failure susceptibility, defined as “Matrix of Failure at Mining Rock Slope”. Slopes with medium–high and high failure susceptibility are selected for a stability analysis, with a probabilistic approach using the probability of failure calculation, and slopes with low and medium failure susceptibility can be evaluated using deterministic approach.