Abstract

The generation of a subsidence crater on the surface derived from an underground mine exploitation, has been under study since the 70’s with works done by Peck (1969), Shandbolt (1978), Kvapil et al (1989) and Flores (2005), among the most famous. All these studies were developed using available observations together with the characterization of rock massifs and materials disposition, to elaborate rules that would allow the estimation of the extension of motion caused by the phenomena of subsidence.

Since 2010, El Teniente mine of CODELCO – CHILE has been monitoring the ground subsidence generated by the underground exploitation using radar satellite data (InSAR) by applying methods based in differential interferometry (DInSAR). This has allowed obtaining accurate ground motion measurements over large extensions of land, which have been used to develop a behavior model that establishes a link cause-effect between the underground works and surface subsidence. This conceptual model represents a consistent relationship between underground mining and subsidence development on the surface.

These analyses have been applied in the delineation of the subsidence effect and in the development of a conceptual model for the subsidence process that is generated by the phenomena from the base of the exploitation up to the surface. The results indicate a significant difference between the traditional estimation of subsidence angles and results obtained from inSAR technology. Finally, the subsidence interpretation using interfereometric satellite methodologies show a reduction of the extension effect on the surface due to underground drawing with a consequent reduction in angles of breaking and influence.

1. INTRODUCTION

Today, the availability of technologies such as InSAR, has allowed us to build digital terrain models (DTM) with high accuracy and updating periods in the order of 10 days. These measurements have been carried biannually since 2011 (due to the snow in winter no measurements are made) Thus, to date there exist sufficient measurements with which to generate a model of behavior that allows estimation of the range of subsidence parameters as a function of mining, geotechnical and environmental efforts.

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