Rock stress tensor measurements at El Teniente Mine, Chile

Windsor, Christopher R; Cavieres, P; Villaescusa, Ernesto; Pereira, Joseph

doi:10.1201/9781439833650.ch9

Cited by 8 publications

(4 citation statements)

References 4 publications

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“…Hayashi et al 1979;Jupe et al 1992;Seto et al 1992;Momayez and Hassani 1992;Jingen et al 1995;Barr et al 1999;Ishiguro et al 1999;Seto et al 1999;Watanabe et al 1999;Wang et al 2000;Villaescusa et al 2002;Ulusay et al 2003;Windsor et al 2006;Villaescusa et al 2006) assumed that the KE value determined for an oriented core was equal to the in situ normal stress as suggested by Kanagawa et al (1976). In some of these studies, the results obtained from the AE method were compared with those obtained by overcoring and hydraulic fracturing methods for the same sampling locations.…”

Section: Introductionmentioning

confidence: 97%

Comparison of stresses obtained from Acoustic Emission and Compact Conical-Ended Borehole Overcoring techniques and an evaluation of the Kaiser Effect level

Tuncay

2011

Bull Eng Geol Environ

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The purpose of the study was to compare stress values obtained from Acoustic Emission and Compact Conical-Ended Borehole Overcoring stress measurement techniques applied at an underground limestone mine in Japan, and to investigate the effect of rock anisotropy and confining pressure on the Kaiser Effect level which has been used to determine in situ stresses by the Acoustic Emission technique. Initially, Acoustic Emission tests were carried out on limestone cores extracted from horizontal boreholes in a pillar and hanging wall in the underground mine. The stress values obtained were two or three times greater than those obtained by the Compact Conical-Ended Borehole Overcoring method. In the second stage, the anisotropy of a granite block was determined by P-wave measurements. Core specimens extracted from two different directions were pre-loaded under axisymetric triaxial conditions by applying a series of differential stresses. The cores were then re-loaded under uniaxial conditions and the Kaiser Effect levels were determined. It was concluded that both the anisotropy and confining pressure have an important influence on the Kaiser Effect level.

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Section: Introductionmentioning

confidence: 97%

Comparison of stresses obtained from Acoustic Emission and Compact Conical-Ended Borehole Overcoring techniques and an evaluation of the Kaiser Effect level

Tuncay

2011

Bull Eng Geol Environ

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“…Based on this, an elastic estimation is recommended for cave mining, which it was useful to estimate the expected breakdown pressure for deeper areas of El Teniente, as part of this exercise. In addition, in situ high stress field (Windsor et al 2006) in deeper areas of El Teniente, is comparable with Haynesville shale reservoir In Situ stress field. Regardless breakdown pressure for El Teniente is higher (more than 2 times) than Haynesville, mainly explained because of pore pressure conditions and poroelastic behaviour.…”

Section: Geotechnical Environmentmentioning

confidence: 58%

“…Then, hydraulic fractures tend to be vertically, independently the wellbore orientation (see Figure 6). In comparison, Figure 7 shows that σ1 is usually horizontal in most of cave mines in which a preconditioning technique has been applied (Hormazabal et al 2010;Catalan & Suarez 2010;Windsor et al 2006;Jeffrey et al 2010). This means that hydraulic fractures tend to propagate horizontally.…”

Section: Geotechnical Environmentmentioning

confidence: 99%

Hydraulic fracturing in cave mining: Opportunities for improvement

Rimmelin¹,

Chitombo²,

Valdivia³

2020

MassMin 2020: Proceedings of the Eighth International Conference &Amp; Exhibition on Mass Mining

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Hydraulic Fracturing (HF) in cave mining is commonly used in competent rock under high stresses and seismic conditions, to manage risks associated with induced seismicity and cave propagation. The HF process is done using up holes drilled from the undercut level (e.g. El Teniente -Codelco) or down holes from an upper level (e.g. Newcrest mining). Discrete fractures assumed to be in the order of 20 to 40 m in diameter are then created every 1.5 m or 2.5 m along the drill holes, using water at higher pressures. In comparison, other industry experience such as Petroleum, HF is based on similar principles in terms of the drill hole alignment with the principal stresses and the use of water at high pressures, but more efficient during the process of the creation of the network of fractures. The network of fractures thus created covers a volume rather than discrete fractures and could be as long as 100 m. Currently, petroleum HF process is carried out from the surface down to 3,000 m in depth. Also, the use of additional materials such as "sand" to improve the propagation of fractures is another example of Petroleum practices that can be used in Cave Mining. Another point of discussion relies on the current practices in Cave mining, in which, stress anisotropy is not considered to address important topics such as efficiency of the HF process and spatial distribution of the HF holes, for a better coverage of the rock mass. Hydraulic Fracturing is increasingly becoming an essential enabling tool in deep hard rock cave mining, and some of the current HF practices used in the Petroleum industry offer an opportunity to improve the cave mining HF processes. This paper proposes the use of known rock mechanics principles for the cave mining industry to adopt practices used in the Petroleum to achieve the intended outcomes from HF as currently used in cave mining.

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“…From the Codelco-El Teniente Cu mine in VI Region in Chile. The orebody at El Teniente mine comprises mainly the El Teniente Mafic Complex (CMET, Andesite), Dacite Porphyry, Tonalite, Diorite Porphyry and the Breccia Braden Complex [16]. The ore, which consists of porphyry copper sulfides, was crushed, milled and concentrated by flotation onsite at 2,300 m altitude in the Andes Mountains.…”

Section: Methodsmentioning

confidence: 99%

Suspended electrodialytic extraction of toxic elements for detoxification of three different mine tailings

Jensen¹,

Ottosen²,

Hansen

et al. 2016

Int. J. SDP

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Environmental effects of mining activities partly origin from the production of tailings, and the exposure of these to ambient physical and chemical conditions. Removal of toxic elements from tailings prior to deposition could improve environmental performance and reduce risks. Experimental results have shown that electrokinetic treatment can remove Cd, Cu, Pb, and Zn from tailings soils; As from tailings; and Cu from tailings. Still, however, a major concern is the long treatment-time required for the element-transport through the tailings matrix. Therefore several enhancement methods have been investigated including pre-treatment of the tailings with acid; insertion of bipolar electrodes; and implementation of pulsed or sinusoidal electric fields. In line with these efforts, we investigated the efficiency when extracting toxic elements from a suspension of tailings, rather than from a solid matrix, which could well be implemented as a final treatment step prior to deposition of tailings. Six electrodialytic experiments in laboratory scale with three different mine tailings (Codelco, Zinkgruvan, and Nalunaq) show that it is possible to extract residual Cu from the all the three suspended mine tailings, although with some difference between the tailings. From the Zinkgruvan sediment, which had the lowest Cu removal, Pb could also be extracted, while Cd and Zn were less extractable.

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Rock stress tensor measurements at El Teniente Mine, Chile

Cited by 8 publications

References 4 publications

Comparison of stresses obtained from Acoustic Emission and Compact Conical-Ended Borehole Overcoring techniques and an evaluation of the Kaiser Effect level

Comparison of stresses obtained from Acoustic Emission and Compact Conical-Ended Borehole Overcoring techniques and an evaluation of the Kaiser Effect level

Hydraulic fracturing in cave mining: Opportunities for improvement

Suspended electrodialytic extraction of toxic elements for detoxification of three different mine tailings

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