Quality of reconstituted tailings samples based on their mechanical response

¹ University of Coimbra, Civil Engineering Department, joaopsvo@hotmail.com, Portugal
² Univ Coimbra, CITTA- Research Centre for Territory, Transports and Environm, Civil Eng. Dep, pac@dec.uc.pt
³ Polytechnic Institute of Coimbra, Coimbra Institute of Engineering, CITTA, SUScita, lmsantos@isec.pt

Abstract

With a growing global population and greater environmental awareness modern societies inevitably need more mineral resources. Thus, an increase in mining activity is expected through the reactivation of old mines and/or the licensing of new explorations. Increased mining operations will lead to the production of higher volumes of tailings that often endanger people and the environment.

To suitably assess the behaviour of tailings, it will be necessary to carry out a complete and exhaustive laboratory characterisation in order to determine the necessary parameters for the correct sizing of the tailings disposal structures. In this sense, for a successful laboratory work, it is necessary to obtain good quality intact or remoulded samples for testing and comparison. However, good quality intact samples of tailings are rarely available. Therefore, reconstituted samples assume an important role. Currently the most commonly used reconstitution methods for mine tailings are the moist tamping and slurry methods.

This paper aims to discuss the potential of the most commonly used sample reconstitution methods in mine tailings. Some mechanical characterisation studies of tailings are also presented, namely when subjected to monotonic and cyclic stresses, with the aid of triaxial and oedometer equipment. Complementary tests with unusual equipment, such as Hollow Cylinder Apparatus (HCA) and bender elements, are also presented. Finally, and in view of the research carried out, the main limitations in laboratory tests carried out on these materials are identified.