Project

Back to overview

Mineralogical and geochemical characterization of selected supergene profiles and reactive transport modeling of supergene enrichment and exotic mineralization at Chuquicamata, Chile

Applicant Fontboté Lluis
Number 146484
Funding scheme Project funding (Div. I-III)
Research institution Département des sciences de la Terre Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Geochemistry
Start/End 01.05.2013 - 30.09.2014
Approved amount 72'600.00
Show all

All Disciplines (2)

Discipline
Geochemistry
Mineralogy

Keywords (9)

drainage; geochemistry; deposits; metallogeny; enrichment; ore; supergene; acid; mining

Lay Summary (French)

Lead
Chuquicamata est un gisement de cuivre de type porphyre. Lorsque ce type de gisement est proche de la surface, l’eau de pluie libère les métaux, en général à une faible teneur, et les transporte. Dans des conditions chimiques favorables, ces métaux reprécipitent, sous forme de nouveaux minéraux, en général avec des teneurs plus hautes que dans le gisement primaire.L’ensemble de ces processus de lessivage, mobilisation, et précipitation est regroupé sous le terme de processus supergènes.
Lay summary

A Chuquicamata, ces processus supergènes ont formé une zone enrichie dans le porphyre lui-même (transport vertical), et un nouveau gisement en aval, dit exotique (transport latéral).

Les gisements de type porphyre ne sont souvent économiquement intéressants que grâce  aux processus supergènes. L'intérêt de leur compréhension est donc économique, mais il est aussi environnemental: les mêmes mécanismes chimiques interviennent lors de la mobilisation de métaux dans des déchets miniers et sont alors une source de pollution.

L'étude a pour but de comprendre dans leur ensemble les processus supergènes à Chuquicamata. Cela implique une compréhension:

- régionale (chronologie relative et intégration dans le contexte tectonique et climatique) ;

- locale (circulation des fluides dans le système) ;

- géochimique (interactions fluide-roche et modélisation).

Ce travail permettra de clarifier certains aspects de la formation d’un des plus importants gisements de cuivre au monde, en obtenant des données  nécessaires pour  développer des  nouveaux outils d'exploration et en même temps et de donner de nouvelles pistes d'action dans des problématiques environnementales.


 

Direct link to Lay Summary Last update: 15.05.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Reported supergene sphalerite rims at the Chuquicamata porphyry deposit (northern Chile) revisited: evidence for a hypogene origin
Pinget M. M.-C. Dold B. Zentilli M. and Fontboté L. (2015), Reported supergene sphalerite rims at the Chuquicamata porphyry deposit (northern Chile) revisited: evidence for a hypogene origin, in Economic Geology, 110(1), 253-262.

Collaboration

Group / person Country
Types of collaboration
Prof. Dr. Bernahrd Dold/Universidad de Chile, Santiago Chile (South America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Associated projects

Number Title Start Funding scheme
129988 Mineralogical and geochemical characterization of selected supergene profiles and reactive transport modeling of supergene enrichment and exotic mineralization at Chuquicamata, Chile 01.05.2010 Project funding (Div. I-III)

Abstract

The project "Mineralogical and geochemical characterization of selected supergene profiles and reactivet transport modeling of supergene enrichment and exotic mineralization at Chuquicamata, Chile" and the related Ph. D. Thesis project of Marie Caroline Pinget started the 1st May 2010 which is supervised jointly by the PI and Prof. B. Dold Universidad de Chile at Santiago. A prolongation for a last period of 12 months is requestedherewith.A first goal of the project is to characterize mineralogically and geochemically selected supergene profiles in Chuquicamata and Exotica, with the scope of tracking the mineralogical changes due to sulfide oxidation. Main tools are optical mineralogy, XRD, and differential XRD (DXRD), XRF and micro XR Fluorescence, SEM microscopy and sequential extraction analyses. The mass-transfer from the sulfide fraction to the different secondary mineral groups is being quantified. Also porosity, density, permeability, structures, fractures, and faults observed in the core samples is being mapped in order to reconstruct the flow system for the reactive transport modeling.The correlation degree between sulfide enrichment and neutralization potential of the host rock in Chuquicamata should give indication how the geometry and secondary mineralogy of supergene processes isinfluenced by the hydrothermal alteration pattern (which largely controls the neutralization potential of the host rock). Similarly, the correlation degree between alteration intensity, mineral assemblage and NP of the gangue mineralogy in the Exotica deposit is examined. This is done by a detailed description of the mineralogy and geochemistry in the open pit of Exotica and with drill cores from the mined part to obtain information about the complete geometry of the system. A stable isotopic study will help to trace the principal oxidants implied in the formation of the oxidationprofiles and in each studied sites (atmospheric oxygen or ferric iron).Reactive transport modeling of different formation scenarios and calibration of the model: Based on the mineralogical, geochemical, and textural findings, different formation scenarios will be tested by reactive transport modeling and the model will be calibrated with the geochemical and mineralogical data set.The project has advanced according schedule for its first 30 months, the descriptive part being largely finished and elements of the interpretation too. Three extended abstracts have been published.
-