A Methodology Based on Magnetic Susceptibility to Characterize Copper Mine Tailings

Elizabeth J Lam,Rodrigo González,Manuel Cánovas,Eugenio A Veloso,Antonio Bernardo,Fernando A Álvarez,Rodrigo Carle,Ítalo L Montofré

doi:10.3390/min10110939

Abstract

This paper intends to validate the application of magnetic techniques, particularly magnetic susceptibility, as sampling tools on a copper tailings terrace, by correlating them analytically. Magnetic susceptibility was measured in both the field and laboratory. Data obtained allowed for designing spatial magnetic susceptibility distribution maps, showing the horizontal variation of the tailings. In addition, boxplots were used to show the variation of magnetic susceptibility and the concentration of the elements analyzed at different depths of the copper tailings terrace. The degree of correlation between magnetic and chemical variables was defined with coefficient R2. The horizontal and vertical variations of magnetic susceptibility, the concentration of elements, and the significant correlations between them show a relationship between magnetic susceptibility and the chemical processes occurring in the tailing management facility, such as pyrite oxidation. Thus, the correlation functions obtained could be used as semiquantitative tools to characterize tailings or other mining residues.

Highlights

The treatment of extensively distributed solid wastes generated by metallurgical processes is a challenge for the environmental sustainability of mining regions [1,2]
magnetic susceptibility (MS) measurements may provide further data about soil pollution to estimate the environmental situation in a study area; i.e., magnetic properties show depth variations, which reflect concentration changes, depth being an environmental soil pollution indicator
A positive linear correlation of magnetic susceptibility with Cr, Fe, Ni, and Cu was observed in the tailings studied, while in the second-grade model a correlation was found for Cu, Zn, and Cr

Summary

Introduction

The treatment of extensively distributed solid wastes generated by metallurgical processes is a challenge for the environmental sustainability of mining regions [1,2]. The physical (pH, density) and the chemical properties of soils are a forcing factor for the growth and pollutant metabolism of plants during phytoremediation, heavy metal content in the sediments at the (superficial) upper levels [5,6] In this context, heavy metal concentration is commonly determined by a chemical analysis involving a high cost and a long period of analysis [7,8,9]; a low-cost and fast-application method is necessary for effective sediment characterization prior to remediation. Sampling quality is essential for estimating the extent of contamination on-site and, establishing intervention requirements to protect human health and the ecosystem integrity [10] In this regard, sampling design plays a fundamental role in the tailing characterization stage and must be based on the spatial contamination distribution hypothesis formulated from the results of the exploratory phase of the study. This scheme must be flexible enough to make adjustments during field activities, owing to, for example, lack of access to preselected sites, unforeseen soil formations, and climatic conditions [15]

Objectives

Methods

Conclusion