Arenal Deeps: application of numerical methods to 2D and 3D stability analyses of underground excavations

Iñaki García Mendive, Uriel Sterin, Gonzalo Rellán and Alejo Sfriso
Monday, August 29, 2016
First presented: 
Eurock 2016 - Cappadocia, Turkey
Rock Mechanics

Arenal Deeps is an Au mine located near Minas de Corrales, Uruguay, which was exploited via an open pit operation from 2004 until 2009 and underground since then, using both inclined room and pillar and transversal stoping methods. The progression of mining activities (down to ~320m BGS) has led to an ever-growing complexity in the geometry of the mine, which cannot be adequately assessed solely with empirical design methods. This work presents a case study in which empirical and numerical methods were integrated to assess the stability of a stope roof and adjoining pillar. Empirical methods enabled straightforward determination of the need to include an intermediate pillar. A 3D boundary element model indicated that stress concentration in the roof was the main driver for instability. The 2D finite element model provided a FoS for roof failure of 1.20, considered adequate given the conservative plane-strain hypothesis it entails and geomechanical uncertainty.

Feature Author

Alejo Oscar Sfriso

Alejo Sfriso has 25 years of experience in geotechnical engineering for infrastructure and mining works. He is an expert in the application of numerical methods for geotechnical design and analysis. Alejo belongs to twelve professional associations, including ISSMGE, IAEG, ISRM, IGS, ICOLD, IACMAG, ITA, ASCE and its corresponding chapters in Argentina. He was member of the Executive Committee of the Argentinean Society for Geotechnical Engineering in the period 1997 - 2015, being the President of the Society (2011-2015). Alejo serves as Professor at the University of Buenos Aires since 1989 and at the University of La Plata between 1996 and 2015, in the subjects of Soil Mechanics, Rock Mechanics and Foundations. He also serves as jury member for faculty positions and theses, reviewer of journals, member of advisory committees, conference organizing committees, and departmental councils at the Faculty of Engineering of University of Buenos Aires, among others.

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