Espinosa E.A.,Codelco Chile |
49th US Rock Mechanics / Geomechanics Symposium 2015 | Year: 2015
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 in SAR 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. Copyright 2015 ARMA, American Rock Mechanics Association.
Castillo P.I.C.,University of Chile |
Townley B.K.,University of Chile |
Emery X.,University of Chile |
Puig A.F.,Codelco Chile |
Deckart K.,University of Chile
Geochemistry: Exploration, Environment, Analysis | Year: 2015
The Campanani, Casualidad and Inca de Oro prospects, owned by Codelco-Chile, are extensive areas covered by post-mineralization deposits. To assist the detection of potential exploration targets, we carried out basic soil gas sampling campaigns by means of the Ore Hound GOCC® passive collectors, which were buried on a regular grid at a depth of 30–40 cm. After 90–120 days, samples were retrieved, sealed, and adsorbent material was submitted to an acid elution and analysed by ICP-MS for a set of 72 elements. In this study, databases have been analysed and modelled by statistical and geostatistical methodologies, mainly by factorial kriging analysis (FK). In all cases, a systematic analytical error was detected, discriminated and filtered, allowing the definition of contrast anomalies at different scales of spatial variation, and the interpretation of evidence of secondary dispersion processes by which present time surface contrast anomalies have been developed. The interpretation of contrast anomalies and element associations allowed the recognition of structural influences as pathways for gaseous circulation at the Campanani and Casualidad prospects. Likewise, lithological controls were detected at the Campanani and Inca de Oro prospects. At the Casualidad Prospect, a Co-Sn-Cu association describes a prospective zone c. 2 km north of the Casualidad deposit. At the Inca de Oro prospect, a marked influence of groundwater flow and/or surface drainage has been recognized in the configuration of contrast anomalies. © 2015 AAG/The Geological Society of London.
Potvin Y.,University of Western Australia |
Jarufe J.,Codelco Chile |
Wesseloo J.,University of Western Australia
Transactions of the Institutions of Mining and Metallurgy, Section A: Mining Technology | Year: 2010
Reservas Norte (RENO) is one of the panel caving sectors of El Teniente mines, owned by Codelco Chile. The sector has experienced mine induced seismicity for many years. The work presented in this paper focuses on seismic activity recorded between the period from January 2004 to July 2008. The interpretation of the seismic data revealed that the sources of elevated seismic hazard (large events) at RENO during this period could be attributed to four major geological structures: Falla G, Falla F, Falla C, Falla N1. In particular, the seismic response of the four structures to undercut blasting activities is examined in detail. The use of numerical modelling has shown that it is possible to simulate this response after calibrating the model against the cumulative seismic moment released by the faults, as mining advances towards them. This calibrated numerical model can then be used to forecast future seismic responses. The main product of this work is a tool that can be used to rank different undercutting rates and geometries in terms of seismic hazard. © 2010 Maney Publishing.
Oyarzun M.,Codelco Chile |
Arevalo A.,Codelco Chile
GeoMet 2011 - 1st AusIMM International Geometallurgy Conference 2011 | Year: 2011
Direct relationships between rock texture and BWi (grindability index) have been established based on geological and metallurgical information supported by optical microscopy observations, gathered from 731 samples. Each recognised rock texture is observed to be related to a certain BWi range and, this texture is also characteristic of distinct lithological subunits (recognisable at mapping scale). Therefore, this relationship may provide an important tool for early milling in situ estimation. Since each textural type is a response to rock formation conditions, the causality of the relationship between BWi and texture is based on such conditions and, particularly, on the interfacial free energy among its components. According to the abovementioned textural features, the greater the free interfacial energy between mineral components, the greater the necessary energy required to break its grain boundaries and, consequently, the greater the necessary energy required for milling. If the textural evidence indicates that the rock was able to adjust the shape and/or size of its components - in a natural tendency of all systems to minimise energy - then the necessary energy required to break its grain boundaries will be lower.
Epstein R.,University of Chile |
Goic M.,University of Chile |
Weintraub A.,University of Chile |
Catalan J.,Fundacion Para la Transferencia Tecnologica |
And 6 more authors.
Operations Research | Year: 2012
We present a methodology for long-term mine planning based on a general capacitated multicommodity network flow formulation. It considers underground and open-pit ore deposits sharing multiple downstream processing plants over a long horizon. The purpose of the model is to optimize several mines in an integrated fashion, but real size instances are hard to solve due to the combinatorial nature of the problem. We tackle this by solving the relaxation of a tight linear formulation, and we round the resulting near-integer solution with a customized procedure. The model has been implemented at Codelco, the largest copper producer in the world. Since 2001, the system has been used on a regular basis and has increased the net present value of the production plan for a single mine by 5%. Moreover, integrating multiple mines provided an additional increase of 3%. The system has allowed planners to evaluate more scenarios. In particular, the model was used to study the option of delaying by four years the conversion of Chiquicamata, Codelco's largest open-pit mine, to underground operations. © 2012 INFORMS.