Keywords

tailings deposit, wind erosion, phytotechnologies, landscape rehabilitation

Abstract

Landscape integration of mining infrastructures, sites, and environmental liabilities is currently a fundamental area of attention in the sustainable practices of mining production. A conceptual model for the landscape integration and rehabilitation—designed and developed during 2020 and 2021 by a research team of the Pontificia Universidad Católica de Chile (PUC), Pontificia Universidad Católica de Valparaíso (PUCV), Universidad de Santiago de Chile (USACH), and Compañía Minera del Pacífico (CMP)—gave rise to a master Plan for landscape integration and rehabilitation in the southern coastal border of Huasco, in the Atacama region of Chile. As part of this model, in 2020, a Phytotechnological Program was developed that considers technologies based on the use of plants on tailings deposits as an innovative solution to mitigate the emission of particulate material, minimize wind erosion, and improve environmental conditions and safety. Native and endemic plants are recommended, as they are acclimatized to the local environment and favor natural ecological successions. The Huasco Pellets Plant (HPP), located 5 km southwest of Huasco and 700 km north of Santiago de Chile, produces agglomerates of iron minerals (pellets). In compliance with the requirements of the environmental authority, the company presented a Filtered Tailings Deposit (FTD) project with a storage capacity of 14.6 million tons of tailings (7.6 million m3). The project includes the coverage of the tailings with granular material, soil, and vegetation during the progressive closure to integrate the FTD into the landscape, once the operation ceases, to control particulate matter emissions from the FTD during the operation, closure, and post-closure stages of the facility. To meet this goal and guarantee a successful closure of the FTD, a phytotechnological program was developed with the purposes of 1) selecting plant species for the progressive closure; 2) designing and supervising the installation and operation of a plant nursery on site; 3) designing, supervising, and monitoring an experimental pilot of the phytotechnological program, and 4) the elaboration of a methodological guide. To date, the phytotechnological program has achieved the selection of the native plant species Frankenia chilensis, Jarava plumosa, Nolana sedifolia, and Nolana divaricata; the implementation and operation of the nursery; and the tolerance to tailings sands of two of the species, together with the identification of zones differentially affected by wind erosion. The main challenges for the execution of the phytotechnological program are: the governance of the project, the inclusion of the FTD closure plan from the beginning of the operation, the effective communication with the community, the company´s experience in R&D projects, regulations and guidelines for the rehabilitation of mining sites, and the vulnerability of biological systems. We recommend that any phytotechnological program for the rehabilitation and landscape integration of a mining tailings deposit must address these challenges in order to minimize the risk of technological implementation.

DOI