Conference Agenda

This work was carried out on the premises of the Hydro Paragominas Bauxite Mine, located 70 km from Paragominas city in the state of Pará, Brazil. The Paragominas plant is responsible for processing and sending bauxite pulp through a pipeline over 244 km extending to the Hydro Alunorte refinery in Barcarena city also in the state of Pará, Brazil, the main equipment responsible for the production of this pulp are the mills. As a result of cooperation between the maintenance, process and industrial operation engineering sector of Hydro Paragominas and the company Metso Minerals, a customized specification project and optimization of the SAG mill body liners was developed. Previously, the SAG mill linings (162 pieces) were manufactured in steel alloy and due to the comminution process, several parts broke, causing lost production, increased costs and exposure of maintainers to risk. The project aimed to mitigate coating breakages throughout the set's useful life campaign, which is an average of 3 years. To achieve this, the material technology was changed from steel alloy to a hybrid coating (Hardox500 and special rubber), the angle of attack was changed from 20º to 25º and the pieces were unified, which reduced the number of pieces from 162 to 54. With these modifications, “zero” liner breakage throughout the useful life was achieved resulting in OpEx savings of US$540,000/year, an increase in the feed rate in the mill of 29 t/h which represents a gain of US$6,690,000/year and a reduction in risk exposure in the individual coating replacement activity. The coating replacement frequency was previously monthly and was reduced to only occur in Overhaul stops every 3 years, in the risk matrix the risk level went from 12 to 2. The project exceeded all expectations for product application.

Ecosystem restoration following bauxite mining is hampered globally by soil degradation that limits vegetation reestablishment. Our study investigated innovative strategies to promote reforestation by applying of nitrogen-fixing bacteria in seedling cultivation. These bacteria engage in symbiosis with plants, enhancing soil fertility and viability in degraded environments. The research was conducted using the seedling of Clitoria fairchildiana, known for its rapid growth. We examined its response under three conditions: (1) control with no inoculation, (2) inoculated with nitrogen-fixing bacteria, and (3) inoculated with bacteria supplemented with sugar. The addition of sugar aimed to provide an immediate energy source to support the symbiotic process. Seedling growth was measured in height and stem diameter. The bacteria inoculation combined with sugar resulted in the tallest seedlings, with a maximum height of 85 cm, compared to 80 and 60 cm for inoculation without sugar and the control group. Moreover, seedlings from the sugar-enhanced inoculation group exhibited a six-fold higher number in maximum stem diameter, peaking at 6 cm versus 1 cm in the control group. These growth parameters are indicators of a seedling's potential for survival and stability, suggesting successful adaptation and nutrient utilization. The pronounced improvements with bacterial inoculation, particularly with added sugar, point out to be a potential method for accelerating the restoration of vegetation on bauxite-mined lands. This research underscores the advantages of integrating nitrogen-fixing bacteria in reforestation, presenting a sustainable process to improve the rehabilitation. These findings contribute critical insights to the field of sustainable land restoration and ecological recovery.

During the dam construction process, sites adjacent to the construction work are licensed and called Borrow Areas. Due to the intensification of anthropogenic actions, these areas are more susceptible to erosive processes that result in soil movement, silting of water resources, loss of natural habitat, alteration of water quality, loss of local fauna and flora and alteration of the natural environment. Traditionally, the control of erosion processes on slopes is carried out using conventional civil engineering techniques (gabion walls, slope reshaping, etc.). However, Hydro Bauxite & Alumina, which is driven by more sustainable and environmentally friendly actions, takes care of neighboring communities and future generations, and decided to implement techniques with a lower environmental impact. The aim of this case study was to demonstrate soil bioengineering techniques. The target area (borrow area) of the intervention project consists of a large gully with an area of approximately 575 m2, 35.5 m long at its central axis and 9.0 m deep at its highest point, with slopes of 77° there are also negative effects visible at various points. Soil bioengineering focuses on a set of techniques that combine living/inert constructive materials, which can be applied as constructive solutions to structural problems of geotechnical and hydraulic stabilization, control of surface erosion processes, and simultaneously design ecosystems in dynamic balance, environmentally friendly and with less damage to nature. In this way, the following techniques were implemented: 1- Earthworks; 2- Live wooden cribwall; 3- Live slope grid; 4- Vegetated coir logs; 5- Selection of suitable plants. This case study presents the techniques used to stabilize the gully. The results were totally effective in controlling erosion and stabilizing the slope, withstanding high volumes of precipitation (82.70mm). There is no need for decommissioning works, as the structures will be integrated into the environment and are more economically viable than traditional molds.

The Global Industry Standard on Tailings Management (GISTM) endeavors to achieve “zero harm to people and the environment” [1]. The GISTM is a sturdy framework, underpinned by a plan-do-check-act approach to tailings management, developed to improve the safety and sustainability of tailings facilities in the industry.

It changed the mining industry's approach to accountability, transparency, and safeguarding the rights of project-affected people. The Standard was launched in August 2020 by the Principle for Responsible Investment (PRI) in partnership with the UNEP Finance Initiative and UN Global Compact, the United Nations Environmental Program (UNEP), and the International Council on Mining & Minerals (ICMM). The standard is framed into six topic areas, 15 principles, and 77 requirements. The project-affected people standards are addressed in Topic I. Topic II demands from the operators the development of knowledge about the social, environmental, and local economic context for a given tailings facility. Topic III deals with the standards for designing, constructing, operating, maintaining, monitoring, and closing tailings facilities. In addition, Topic IV focuses on management and governance on a continuous basis. Emergency preparedness and response plans (EPRP) are covered in Topic V, while Topic VI requires the operator to publicly disclose relevant information about tailings facilities to strengthen public accountability. Members of the ICMM committed to implementing GISTM by August 5th, 2023, at tailings facilities (TFs) with “extreme” and “very high” consequence classification and to its other TFs by August 5th, 2025. This paper will present Hydro Bauxite and Alumina’s pathway to successfully implement GISTM at all TFs located at the Alunorte alumina refinery and Paragominas bauxite mine in the Brazilian state of Pará. The Hydro B&A’s implementation process was based on the GISTM Conformance Protocols [2] and has been assessed and confirmed through a self-assessment. The self-assessment demonstrated that Hydro B&A is well-positioned to continuously pursue best practices, enhance tailings safety and environmental stewardship, and be committed to fostering sustainable industrial operations and building trust in practitioners, communities, and investors.