Los impulsores de la conductividad hidráulica en suelos enmendados con residuos de licor verde: aplicación a la recuperación de sitios mineros generadores de ácido

Abstract

The mining industry produces massive amounts of waste that in contact with oxygen can result in leaching of metals. Access to a suitable cover-material for the mine waste is sometimes limited, creating a driving force for recycling industrial residues for these purposes. Green liquor dregs (GLD), an industrial residue from paper and pulp production, has the potential to be used in a sealing layer as an amendment to till. Though hydraulic conductivity is commonly used to evaluate the quality of the sealing layer, field application from laboratory investigations is challenging as many factors, apart from vast variations in the physical properties of both the till and the GLD, control hydraulic conductivity. In this study, 5–20 wt.% of GLD from two different paper mills, with different total solid contents and particle size distributions, were mixed with a silty till with varying total solid contents to investigate how the materials’ dry density, initial water content, and compaction affects the hydraulic conductivity. We found that the initial water content of the materials was the most important factor. With a drier till and GLD, more GLD should be added to attain the lowest hydraulic conductivity possible. The compaction was not found to notably affect the mixtures’ hydraulic conductivity.

Instrumentation of a sealing layer made of a green liquor dregs- and bentonite amended till – Remediation of sulfidic mine waste

“…Some things in this eld study did not go as planned, for example the plan was to install instruments in both the slope and the plateau of the dry cover. But, due to shortage of GLD with the right properties (see Nigéus et al 2023c for more information), the plan changed to install instruments in the GLD-amended till and the bentonite amended till that was used instead of the GLD in the majority of the sealing layer.…”

“…The cover solution consists of sealing layers made of two different materials, a mixture of till and 10 wt.% of GLD, and a mixture of till and 4 wt.% of bentonite. This eld application is described further in Nigéus et al (2023c) The objectives of the study were (i) to install and evaluate the instrumentation of a sealing layer made of GLD-and bentonite amended till (respectively), and ii) to evaluate two different methods of installation: monitoring wells and pits. The evaluation and monitoring of mine waste covers are well studied (e.g., Adu-Wusu and 2 Materials and methods…”