There is a need to define mine tailings in a clear, precise, multidisciplinary, transdisciplinary, and holistic manner, considering not only geotechnical and hydraulic concepts but also integrating environmental and geochemical aspects with implications for the sustainability of mining. This article corresponds to an independent study that answers questions concerning the definition of mine tailings and the socio-environmental risks linked with mine tailings chemical composition by examining the practical experience of industrial-scale copper and gold mining projects in Chile and Peru. Definitions of concepts and analysis of key aspects in the responsible management of mine tailings, such as characterization of metallic–metalloid components, non-metallic components, metallurgical reagents, and risk identification, among others, are presented. Implications of potential environmental impacts from the generation of acid rock drainage (ARD) in mine tailings are discussed. Finally, the article concludes that mine tailings are potentially toxic to both communities and the environment, and cannot be considered as inert and innocuous materials; thus, mine tailings require safe, controlled, and responsible management with the application of the most high management standards, use of the best available technologies (BATs), use of best applicable practices (BAPs), and implementation of the best environmental practices (BEPs) to avoid risk and potential socio-environmental impact due to accidents or failure of tailings storage facilities (TSFs).

How mine tailings storage facilities (TSF) are managed reflects the history, regulatory framework, and environment of a country and locale of the mine. Despite many attempts to find an environmentally friendly strategy for tailings management and governance that balances the needs of society and the ecosystem, there is no worldwide agreement regarding the best practices for tailings management and governance. This article reviews the evolution of copper tailings management and governance in Chile, current practices, and changes that could be or may need to be made to improve practices in response to local environmental conditions and local tolerance for risk. The progress to date in developing a holistic tailings management strategy is summarized. This article also describes recent proposals for the best available technologies (BATs), case histories of Chilean TSF using conventional technology, thickened tailings, paste tailings, filtered tailings, water use reduction, tailings reprocessing to obtain rare earth elements (REEs), circular economy, submarine deep-sea tailings disposal, and ways to avoid failure in a seismic region. Finally, the Chilean tailings industry’s pending issues and future challenges in reducing the socioenvironmental impacts of tailings are presented, including advances made and lessons learned in developing more environmentally friendly solutions.

The generation of tailings in the world today is immense, since only ounces or pounds of metals are extracted for each ton of ore processed. In 2022, it was estimated that more than 14 billion metric tons of mining tailings were produced per year in the world. Currently, many environmental problems associated with tailings management in both Chile and Peru are related to the potential contamination of soil, water, and air. In this article, the environmental impacts caused by tailings storage facility accidents where spills have occurred are analyzed, describing and characterizing: (i) the magnitude of the impacted area, (ii) identification of the sources, i.e., exposure routes, receptors, and (iii) an interpretive analysis of the physicochemical quality of the spilled material, the soil, the water, and the air with respect to local and international regulations. The case studies analyzed in this article correspond to tailings spills derived from the extraction of precious metals (Au, Ag) and heavy metals (Cu, Pb, and Zn) present in the minerals that dominate Chilean and Peruvian mining. Finally, environmental management measures are proposed aimed at mitigating the environmental impacts caused by the spill and remediation alternatives for the sites impacted.

Nowadays, monitoring aspects related to sustainability and safety in mining activities worldwide are a priority, to mitigate socio-environmental impacts, promote efficient use of water, reduce carbon footprint, use renewable energies, reduce mine waste, and minimize the risks of accidents and fatalities. In this context, the implementation of sensor technologies is an attractive alternative for the mining industry in the current digitalization context. To have a digital mine, sensors are essential and form the basis of Industry 4.0, and to allow a more accelerated, reliable, and massive digital transformation, low-cost sensor technology solutions may help to achieve these goals. This article focuses on studying the state of the art of implementing low-cost sensor technologies to monitor sustainability and safety aspects in mining activities, through the review of scientific literature. The methodology applied in this article was carried out by means of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and generating science mapping. For this, a methodological procedure of three steps was implemented: (i) Bibliometric analysis as a quantitative method, (ii) Systematic review of literature as a qualitative method, and (iii) Mixed review as a method to integrate the findings found in (i) and (ii). Finally, according to the results obtained, the main advances, gaps, and future directions in the implementation of low-cost sensor technologies for use in smart mining are exposed. Digital transformation aspects for data measurement with low-cost sensors by real-time monitoring, use of wireless network systems, artificial intelligence, machine learning, digital twins, and the Internet of Things, among other technologies of the Industry 4.0 era are discussed.

In the last 20 years many mining projects around the world have applied a tailings deposition technology named “dry stacking of filtered tailings” at tailings storage facilities (TSFs). This technique produces an unsaturated cake that allows storing this material without the need to manage large slurry tailings ponds. The application of this technology has accomplished: (i) an increase in tailings water recovery, (ii) a reduction of the TSF footprint (impacted areas), and (iii) a decrease in the risk of physical instability, being TSFs self-supporting structures under compaction (such as dry stacks), and (iv) a better regulator and community perception satisfying the need of stable TSFs. This paper presents the main features, benefits, and advances in filtered tailings technology applied in Chile and Peru with emphasis on: (i) filtering technology evolution over the last decade: description of main equipment, advantages, and disadvantages, (ii) design considerations for main TSF geometrical configurations, tailings transport and placement systems, TSF water management, TSF operational and emergency plans, and TSF progressive closure, (iii) operation experiences at site-specific conditions, (iv) technology acceptance in regulatory frameworks, (v) lessons learned and advances, and (vi) new trends and future developments, considering technical, environmental, regulatory frameworks and cost-effective manners.

Underground mines are considered one of the riskiest facilities for human activities due to numerous accidents and geotechnical failures recorded worldwide over the last century, which have resulted in unsafe labor conditions, poor health outcomes, injuries, and fatalities. One significant cause of these accidents is the inadequate or nonexistent capacity for the real-time monitoring of safety conditions in underground mines. In this context, new emerging technologies linked to the Industry 4.0 paradigm, such as sensors, the Internet of Things (IoT), and LoRaWAN (Long Range Wide Area Network) wireless connectivity, are being implemented for planning the efficient, safe, and sustainable performance of underground mine labor environments. This paper studies the implementation of an ecosystem composed of IoT sensors and LoRa wireless connectivity in a data-acquisition system, which eliminates the need for expensive cabling and manual monitoring in mining operations. Laying cables in an underground mine necessitates cable support and protection against issues, such as machinery operations, vehicle movements, mine operator activities, and groundwater intrusion. As the underground mine expands, additional sensors typically require costly cable installations unless wireless connectivity is employed. The results of this review indicate that an IoT LoRaWAN-based wireless sensor network (WSN) provides real-time data under complex conditions, effectively transmitting data through physical barriers. This network presents an attractive low-cost solution with reliable, simple, scalable, secure, and competitive characteristics compared to cable installations and manually collected readings, which are more sporadic and prone to human error. Reliable data on the behavior of the underground mine enhances productivity by improving key performance indicators (KPIs), minimizing accident risks, and promoting sustainable environmental conditions for mine operators. Finally, the adoption of IoT sensors and LoRaWAN wireless connectivity technologies provides information of the underground mine in real-time, which supports better decisions by the mining industry managers, by ensuring compliance with safety regulations, improving the productive performance, and fostering a roadmap towards more environmentally friendly labor conditions.