Arenal Deeps: application of numerical methods to two- and three- dimensional stability analyses of underground excavations

Iñaki García Mendive, Uriel Sterin, Gonzalo Rellán, Alejo O. Sfriso
Wednesday, November 18, 2015
First presented: 

Arenal Deeps is an Au mine located near Minas de Corrales, 400km north of Montevideo, Uru- guay. The Arenal deposit is a subvertical fault zone, 6m – 30m wide, which was exploited via an open pit op- eration from 2004 until 2009 and underground since then. Underground mining is developed using both in- clined room and pillar and transversal stoping methods, the choice depending on the thickness and dip of the mineable zones within the orebody. Current operations extend down to ~320m below ground surface.

Progression of mining activities within the orebody have led to an ever-growing complexity in the geometry of the underground mine and to numerous interferences within stopes, access tunnels and chutes. Empirical design methods, used so far for geotechnical assessment of the stability of stopes, failed short for analysing the increasing complexity of the operation. Two- and three-dimensional numerical analyses have been then carried out in order to compute stress fields and check stress concentrations under tight dilution control re- quirements.

This work presents the results of some of such 2D and 3D numerical models, the procedures employed to cal- ibrate the input parameters, and a short discussion on the numerical aspects of the different computer codes employed in the calculations.

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