Application of Geomechanical Classification Systems in a Tourist Mine for Establishing Strategies within 3G’s Model

Abstract

Stability problems in rock masses are one of the main causes of subsidence events in underground mining areas. Zaruma, in the South of Ecuador, is characterised by mineral wealth, in which 65% of the population depends directly on artisanal mining activity. However, mineral extraction, without technical considerations and in many cases illegal, has negatively impacted the stability of tunnels generated under the city’s urban area, reporting subsidence events in recent years. The aim of this study is to geomechanically characterise the main gallery of the tourist mine “El Sexmo” using two classic methods of geomechanical classification for the configuration of a model that complies with the 3G’s (geotourism, geoconservation, and geoeducation) and supports the culture of sustainability in all areas of the sector. The methodology consists of (i) a field study design, (ii) a geological–geomechanical survey of the rock mass of a tourist mine using rock mass rating (RMR) and the Q-Barton index, and (iii) establishing a 3G’s model for sustainable development. The results reveal that 100% of the rock mass of the tourist mine presents a rock quality classified as “Fair” (class III) by the RMR method, while, via the Q-Barton method, 92.9% of the rock mass obtains a “Poor” rating, except for station S05, rated “Very Poor”. Furthermore, the study proposes additional support measures for three specific stations based on Q-Barton assessments, including fibre-reinforced sprayed concrete and bolting and reinforced ribs of sprayed concrete, considering that the mine is more than 500 years old and maintains geological features for geoeducation in geotechnical mining. Technical and social problems demand an innovative strategy, which, in this work, focuses on the 3G’s model based on the quintuple innovation helix to develop sustainable underground geotourism.