Sustainability in the Minerals Industry: Seeking a Consensus on Its Meaning

Selective recovery of antimony from Sb-bearing copper concentrates by integration of alkaline sulphide leaching solutions and microwave-assisted heating: A new sustainable processing route

The technical feasibility of leaching antimony from an antimony-bearing copper sulphide concentrate, using alkaline sulphide solutions and microwave-assisted and non-assisted heating technology, is investigated at a laboratory scale. The leaching test examines the influence of selective leaching reagent (Na2S and NaOH) concentrations, solid/liquid ratio, and temperature. The results indicate that antimony dissolution is highly selective (e.g. only Sb and As are leached), depending on the concentrations of leaching reagents and the leaching temperature. The influence of temperature on the mineral's dissolution, in the range 25-140 °C, is analysed from a thermochemical point of view using equilibrium databases. Under the optimal conditions: leaching agent: 250 g/L Na2S, 60 g/L NaOH, 2 h, 140 °C, with microwave assisted, the leaching efficiency of Sb reached 95.7 %. The antimony content in the copper concentrate is successfully reduced from 1.1 wt% to <0.2 wt% Sb, making it suitable for copper concentrate metallurgical processing. The study demonstrates that increasing temperature and NaOH/Na2S concentrations collectively enhance leaching efficiency, with a statistical significance, reducing both leaching time and the required temperature, compared to non-microwave-assisted leaching. Furthermore, it is established that excess free hydrogen sulphide ions ensure the efficient dissolution of the main impurities associated with penalties, such as antimony and arsenic, with limited copper and iron dissolution from the copper concentrate, predominantly chalcopyrite. Finally, an integrated hydrometallurgical process flowsheet for antimony removal and recovery from a sulphide copper concentrate is proposed.

Factors affecting the adoption of circular economy in mining companies of developing economies - A Namibian stakeholder perspective

The factors influencing the adoption and implementation of CE in developing countries are not yet fully examined. By focusing on the Namibian mining sector, this study highlights the perspectives of local stakeholders on CE adoption in a developing country. The mine managers recognized that waste is problematic and that CE practices are beneficial for mining companies and Namibia at large. Our findings also indicated that stronger academic institutions providing CE training and helping develop CE solutions, public awareness campaigns, financial support for CE practices, cooperation among industry stakeholders, and clear CE policy would all help drive the implementation of CE.

Revitalizing contaminated lands: A state-of-the-art review on the remediation of mine-tailings using phytoremediation and genomic approaches

The mining industry has historically served as a critical reservoir of essential raw materials driving global economic progress. Nevertheless, the consequential by-product known as mine tailings has consistently produced a substantial footprint of environmental contamination. With annual discharges of mine tailings surpassing 10 billion tons globally, the need for effective remediation strategies is more pressing than ever as traditional physical and chemical remediation techniques are hindered by their high costs and limited efficacy. Phytoremediation utilizing plants for remediation of polluted soil has developed as a promising and eco-friendly approach to addressing mine tailings contamination. Furthermore, sequencing of genomic DNA and transcribed RNA extracted from mine tailings presents a pivotal opportunity to provide critical supporting insights for activities directed towards the reconstruction of ecosystem functions on contaminated lands. This review explores the growing prominence of phytoremediation and metagenomics as an ecologically sustainable techniques for rehabilitating mine-tailings. The present study envisages that plant species such as Solidago chilensis, Festuca arundinacea, Lolium perenne, Polygonum capitatum, Pennisetum purpureum, Maireana brevifolia, Prosopis tamarugo etc. could be utilized for the remediation of mine-tailings. Furthermore, a critical evaluation of the organic and inorganic ammendments that optimize conditions for the remediation of mine tailings is also provided. The focus of this review extends to the exploration of environmental genomics to characterize microbial communities in mining sites. By delving into the multifaceted dimensions of phytoremediation and genomics for mine tailings, this study contributes to the ongoing efforts to revitalize contaminated lands for a sustainable and environmentally friendly future.

Drone-Based Identification of Erosive Processes in Open-Pit Mining Restored Areas

Unmanned Aerial Systems, or drones, are very helpful tools for managing open-pit mining operations and developing ecological restoration activities. This article presents a method for identifying water erosion processes in active quarries by means of drone imagery remote sensing, in the absence of pre-existing imagery or mapping for comparison. A Digital Elevation Model (DEM) with a spatial resolution (SR) >10 cm and an orthophoto with an SR >2.5 cm were generated from images captured with a drone and their subsequent photogrammetric processing. By using Geographical Information Systems tools to process the DEM, a detailed drainage network was obtained, the areas of detected water erosion were separated, and the watersheds in the gullies identified. Subsequently, an estimated DEM before the erosive processes was reconstructed by interpolating the gully ridges; this DEM serves as a reference for the relief before the erosion. To calculate the volume of eroded material, the DEM of Differences was calculated, which estimates the volume difference between the previously estimated DEM and the current DEM. Additionally, we calculated the material necessary for the geomorphological adaptation of the quarry and the slope map, which are two valuable factors closely related to the monitoring of erosive processes. The results obtained allowed us to identify the erosion factors quickly and accurately in this type of mining. In the case of water-filled quarries, it would be important to characterize the subsurface relief. Essentially, the presented method can be applied with affordable and non-invasive materials to create digital grid maps at 10 cm resolution, obtaining data ready for 3D metrics, being a very practical landscape modelling tool for characterizing the restoration evolution of open-pit mining spaces.

Environmental Impacts Related to Closed Mines in Inner Mongolia

Mining activities, while promoting social and economic development, alter the environments and ecosystems of mining areas. Some of the alterations have negative impacts on the environment, while some have positive impacts. By understanding the positive and negative impacts related to closed mines in Inner Mongolia, this research aims to seek advantages of the positive impacts on the environment and reduce the harm of the negative impacts, extending the mining value chain. The paper reviewed four main negative environmental impacts (NEIs) of closed mines and proposed four positive environmental impacts (PEIs) which include ecosystem services, cultural services, land resources and underground space resources, and energy sources and mineral resources. The paper focused on the environmental problems and the PEI utilization of closed mines in Inner Mongolia with 20 representative cases. It carefully studied the Minda Mine which is a good example to combine several PEI utilization objectives. Multiple PEI objectives, as well as the correlations among different objectives, can benefit closed mines ecologically, economically, and socially. In addition, a three-step framework for closed mine revitalization and the factors affecting the compound PEI objectives are mentioned in the paper.

Managing and Reforesting Degraded Post-Mining Landscape in Indonesia: A Review

Tropical forests are among the most diverse ecosystems in the world, completed by huge biodiversity. An expansion in natural resource extraction through open-pit mining activities leads to increasing land and tropical forest degradation. Proper science-based practices are needed as an effort to reclaim their function. This paper summarizes the existing practice of coal mining, covering the regulatory aspects and their reclamation obligations, the practices of coal mining from various sites with different land characteristics, and the reclamation efforts of the post-mining landscapes in Indonesia. The regulations issued accommodate the difference between mining land inside the forest area and outside the forest area, especially in the aspect of the permit authority and in evaluating the success rate of reclamation. In coal-mining practices, this paper describes starting from land clearing activities and followed by storing soil layers and overburden materials. In this step, proper handling of potentially acid-forming materials is crucial to prevent acid mine drainage. At the reclamation stage, this paper sequentially presents research results and the field applications in rearranging the overburden and soil materials, controlling acid mine drainage and erosion, and managing the drainage system, settling ponds, and pit lakes. Many efforts to reclaim post-coal-mining lands and their success rate have been reported and highlighted. Several success stories describe that post-coal-mining lands can be returned to forests that provide ecosystem services and goods. A set of science-based best management practices for post-coal-mine reforestation is needed to develop to promote the success of forest reclamation and restoration in post-coal-mining lands through the planting of high-value hardwood trees, increasing trees’ survival rates and growth, and accelerating the establishment of forest habitat through the application of proper tree planting technique. The monitoring and evaluation aspect is also crucial, as corrective action may be taken considering the different success rates for different site characteristics.

The Potential Re-Use of Saudi Mine Tailings in Mine Backfill: A Path towards Sustainable Mining in Saudi Arabia

The Kingdom of Saudi Arabia covers an area of approximately 2 million km2 and is rich in natural resources that are necessary for industrial development. The estimated mineral wealth beneath the Kingdom’s soil is approximately USD 1.33 trillion, as reported by the Ministry of Industry and Mineral Resources. The Kingdom’s vision for 2030 is to develop the mining sector to become the third pillar of the domestic economy. Therefore, exploration and mining activities are expected to accelerate over the next decade, which will lead to increased waste production. New executive regulations issued in January 2021 contain several sustainable elements related to the environment, social responsibility, and occupational health and safety. Therefore, this study aims to promote an example of sustainable mining activities in the Kingdom that could be adapted to meet the regulatory requirements. Cemented paste backfill samples of varying composition were made with waste materials from a Saudi copper mine for re-injection into underground mining cavities to minimize waste exposure to the environment. The samples were tested for unconfined compressive strength (UCS) after 7, 14, 28, 56, and 90 days of curing. Results from a statistically designed experiment technique show that the samples developed sufficient strength to be used in mine backfilling applications. Strong negative relationships were detected between the UCS and the water-to-binder ratio. There is strong potential for mine backfill technology to be applied to a wide range of Saudi Arabian mines to enhance the sustainability of the mining sector.

A Multiple Criteria Decision Making Method to Weight the Sustainability Criteria of Equipment Selection for Surface Mining

Selection and assessment of mining equipment used in open pit rock mines relies chiefly on estimates of overall exploitation cost. The rational arrangement of mining equipment and systems comprising loading machines, haul trucks and crushing plants should be preceded by a thorough analysis of technical and economic aspects, such as investment outlays and the costs of further exploitation, which largely determine the costs of mining operations and the deposit value. Additionally, the operational parameters of the mining equipment ought to be considered. In this study, a universal set of evaluation criteria has been developed, and an evaluation method has been applied for the selection of surface mining equipment and the processing system to be operated in specific mining conditions, defined by the user. The objective of this study is to develop and apply the new methodology of multi-criteria selection of open pit rock mining equipment based on multiple criteria decision-making (MCDM) procedures, to enable the optimization of loading, handling and crushing processes. The methodology, underpinned by the principles of MCDM, provides the dedicated ranking procedures, including the ELECTRE III. The applied methodology allows the alternative options (variants) to be ranked accordingly. Ultimately, a more universal methodology is developed, applicable in other surface mines where geological and mining conditions are similar. It may prove particularly useful in selection and performance assessment of mining equipment and process line configurations in mining of low-quality rock deposits. Therefore, we undertook to develop universal criteria and applications for the selection and performance assessment of process machines for surface mines, taking into account environmental aspects as well as deposit quality.

The Entropy Model for Sustainability Assessment in Industrial Ecosystems

The aim of this paper is to address the gap in the academic literature towards the development of methodological approaches to the industrial ecosystem sustainability assessment. This study was focused on the industrial ecosystems formed based on an entropy model and implementing the principles of complex systems. This article systematizes the problem of applying the ecosystem approach to cross-industry interaction. A contribution to the literature was achieved by providing a systemic perspective on the sustainable industrial process. In this paper, we develop the methodological foundations to improve the understanding of integration processes’ influence on the industrial ecosystem potential. For a relevant analysis of industrial ecosystem potential, the existing patterns of system functioning were taken into account, including entropy equilibrium and the Harrington model. We illustrate our assumptions with an empirical case study of the National University of Science and Technology (NUST) “MISIS” ecosystem—“Green technologies for resource conservation” (Russia), with an assessment of ecosystem sustainability through the actors’ collaboration level. The propositions arising from this analysis provide information to help academics, policymakers, government, and individual enterprises with a more adequate understanding of the practical mechanisms and tools that help trigger the self-organization and sustainability of the industrial ecosystems.

Transparency for Multi-Tier Sustainable Supply Chain Management: A Case Study of a Multi-tier Transparency Approach for SSCM in the Automotive Industry

Sustainability in supply chain management (SSCM) has become established in both academia and increasingly in practice. As stakeholders continue to require focal companies (FCs) to take more responsibility for their entire supply chains (SCs), this has led to the development of multi-tier SSCM (MT-SSCM). Much extant research has focused on simple supply chains from certain industries. Recently, a comprehensive traceability for sustainability (TfS) framework has been proposed, which outlines how companies could achieve MT-SSCM through traceability. Our research builds on this and responds to calls for cases from the automotive industry by abductively analysing a multi-tier supply chain (MT-SC) transparency case study. This research analyses a raw material SC that is particularly renowned for sustainability problems—the cobalt supply chain for electric vehicles—and finds that the extant literature has oversimplified the operationalisation of transparency in MT-SSCM. We compare the supply chain maps of the MT-SC before and after an auditing and mapping project to demonstrate the transparency achieved. Our findings identify challenges to the operationalisation of SC transparency and we outline how FCs might set to increase MT-SC transparency for sustainability.

Benchmarking Internet Promotion of Renewable Energy Enterprises: Is Sustainability Present?

Sustainability constitutes a broad discipline that focuses on the social, economic and environmental impact of human activities. Many policies and strategies have been developed for the pursuit of environmental sustainability and the guidance to a green society. Many enterprises have taken meaningful steps to improve their own environmental performance through corporate sustainability and environmental management. Environmental management contributes to significant improvements to environmental performance of the enterprises. This paper aims to evaluate the Renewable Energy Enterprises performance in the Internet in Thessaloniki Prefecture regarding the characteristics of sustainability using Multi-criteria Decision Analysis. TOPSIS method was used to provide a ranking of the Renewable Energy Enterprises according to their sustainability and finally conclude to a benchmark. According to the results of the research, the Renewable Energy Enterprises achieve a good level of sustainability but not the optimum. However, the entrepreneurs should adopt modern environmental policy, sustainable marketing, green network framework and certified environmental management system in order to consider their enterprise sustainable.