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A methodology to select valid results from Lab tests to estimate properties of intact rock with microdefects

Andrea Russo, Esteban Hormazabal
Wednesday, June 29, 2016
First presented: 
Published paper
Rock Mechanics

Porphyry copper deposits are characterized by a rock mass with a stockwork of mineralized veins and veinlets affecting the strength behavior of the intact rock and rock mass. The observation of tested samples and blocks at draw points pointed out that veinlets and veins have a high participation in the failure mode, according to this a small volume of rock containing veinlets less than 1mm is considered to be representative of the intact rock. The structural description of the tested samples pointed out four typical failure types and three of them can be considered valid results to estimate the intact rock properties. This failure classification system is useful to define valid results to estimate the intact rock properties. This method had been applied to several operating mines and projects in Chile obtaining a better estimation of the intact rock and rock mass properties and has been applied to estimate pillars strength, fragmentation curves, large open pit slopes stability or cavability for deep underground mines increasing the reliability of the results.

Feature Author

Andrea Russo

Mr. Russo has 25 years of experience in the mining industry. He has worked in porphyry copper deposits such as El Teniente and Chuquicamata underground project acquiring a strong experience in geological, structural and geotechnical mapping for underground mining, geological and geotechnical logging of drill holes and identification and characterization of geotechnical domains and lithologic model update. He has a strong experience in geotechnical characterization of rock mass according to Laubscher, Barton, Bieniawsky and GSI of Marinos & Hoek classification systems, geomechanical laboratory tests analysis, definition of the caving sequence and caving orientation. Definition of ground support through empirical methods such as Barton´s Q and validation through numerical models such as Phase2. He has worked on various open pit projects analyzing slope stability. He has worked on an environmental project acquiring experience in rock mass grouting using the GIN method. For his degree thesis he worked on the genetic model of several ore bodies in SW Sardinia (Italy) (SEDEX type deposits). His doctoral work involved the tectonic - sedimentary evolution of a carbonate platform of the Lower and Middle Cambrian in the NW of Spain and the genetic model of two mineralized levels at the base and top of the formation (SEDEX type deposits).

Principal Geologist (Rock Mechanics)
PhD in Natural Resources
SRK Santiago
Esteban Hormazabal
Esteban is a Civil Mining Engineer and holds a Master of Science (Geophysics) specialized in applied hydrogeology. He has 24 years of specific experience in geotechnical engineering, rock mechanics and geotechnical instrumentation, having worked in different mining and civil engineering projects. 
Additionally, he is an expert in analysis and geomechanical design of underground mining and surface excavations using 2D and 3D numerical modelling, stability analysis and slope design in open pits and waste dumps. 
He has led different and important open pit and underground mining projects in Argentina, Brazil, Chile, Colombia, Kazakhstan, Mexico, Peru, Russia, Uruguay and USA. 
Esteban has authored several publications and has been speaker at different national and international conferences. He is a Competent Person of AusIMM and the Commission for the Qualification of Competencies in Mineral Resources & Reserves of Chile (QP). He has been professor of  the Rock Mechanics Chair at the Universidad Católica de Chile from 2013-2018.


Head of Rock Mechanics Services
Min Eng, MSc (Geophysics), FAusIMM, SAIMM, CRIRSCO
SRK Santiago
SRK North America