Fluoride in mine drainage poses substantial environmental risks, often exceeding South Korea’s regulatory discharge limit of 3.0 mg/L. This study assessed treatment processes combining precipitation and adsorption for fluoride and toxic metals from the Samwon mine drainage. To treat aluminum, manganese, and fluoride, experiments involving injection of calcium hydroxide and reaction with slag-limestone mixture were conducted. Subsequently, to treat remnant fluoride, experiments involving precipitation/adsorption using aluminum sulfate and lanthanum chloride as well as adsorption using Al-rich coal mine drainage sludge and domestic water purification sludge were conducted. The results demonstrated substantial fluoride reduction, with adsorption kinetics following a pseudo-second-order model.

The treatment of water in mining operations is a critical aspect of environmental sustainability. As the demand for minerals and metals continues to grow, the need for effective water treatment solutions has never been more pressing. The discharge of untreated or poorly treated water can have devastating consequences for local ecosystems and communities.

A Swedish metal mine is replacing its existing water treatment system to meet more stringent treatment objectives. This upgrade is necessary to ensure that the mine's water treatment process is able to effectively remove contaminants and meet the required standards. To achieve this, the mine has adopted a collaborative approach, involving a consultant and a technologies supplier from the outset of the project. This approach allows for a comprehensive understanding of the mine's specific needs and the development of a tailored solution that optimizes water treatment.

Through this project, several key findings have emerged. The selection of adequate chemistry, using multiple precipitation mechanisms, is crucial to reduce sludge formation, increase performance and reduce chemical consumption. Additionally, a comprehensive approach to water treatment, taking into account the specific requirements of the mine and the local environment, is essential for effective water management. By prioritizing water treatment and management, mining companies can reduce their environmental impact, improve their social license to operate, and create economic benefits.

The approach taken by this Swedish metal mine provides a model for other mining companies to follow, and highlights the importance of innovation and collaboration in addressing the complex challenges of water treatment in mining operations. As the demand for minerals and metals continues to grow, the need for effective water treatment solutions will only increase. By adopting a proactive and collaborative approach to water treatment, mining companies can ensure that their operations are sustainable, efficient and environmentally responsible.

Two metalliferous mine drainages from El Triunfo 1 (ET) and Santa Teresita (ST) mines in the Ancash region of Peru were selected to assess the feasibility of (semi-)active treatment methods, including the efficiency of As coprecipitation with Fe in inflows. Elevated concentrations of Al, Fe, Mn, and Zn at both mine drainages were reduced to target levels at pH 10. Additionally, the As concentration of 1.69 mg/L at the ET mine was reduced by approximately 93%, reaching 0.124 mg/L at pH 10, suggesting that coprecipitation and adsorption by Fe in the mine drainage played a substantial role in As removal.

An understanding of geochemical reactions and environmental factors that control water quality is required for management and mitigation of environmental effects from acid mine drainage (AMD). This paper describes water-quality modeling tools that were developed to aid in the evaluation of key hydrogeochemical processes and their relative importance in controlling concentrations of dissolved metals and associated constituents in AMD and the effluents from treatment systems.

The mining industry faces environmental and reputational risks due to the toxicity of mine wastewater, which can have devastating consequences for ecosystems and local communities. In gold mining operations, contaminants such as cyanide species, ammonia, and metals can generate a toxic effluent that is harmful to aquatic life. A Canadian gold mine operating in a very cold climate faced recurring toxicity issues, despite implementation of metals removal in its mining effluent, and was pressed by local regulations to address the issue.

A rigorous process of discovery was undertaken to understand the source of the toxicity and identify a suitable solution, taking into account local constraints such as climate and limited footprint. This case study highlights the approach to resolve the toxicity issues, from theoretical to laboratory validation, and then followed by piloting confirmation to lead to the full-scale application. Cyanide species were targeted as the major source of toxicity as well as ammonia, both of which can be treated by enhanced biological degradation through a moving bed bioreactor (MBBR). The biological degradation was implemented in addition to metals removal, in order to completely address all the sources of toxicity.

The study demonstrates the effectiveness of the combined MBBR and metals removal solution in reducing acute toxicity to aquatic life, with five years of data on the full-scale application supporting the findings. The MBBR process successfully degraded cyanide species and ammonia, while the removal of metals, such as copper, upstream of the biological process was crucial to address the toxicity of these metals to the biomass responsible for degrading the cyanide and ammonia. The case study provides valuable insights for the mining sector, showcasing the challenges that were overcome and the innovative solutions for the industrial sector implemented to address the toxicity issues.

The complexity of toxicity in mine water is challenging, and this study demonstrates the importance of understanding the water quality in its entirety to implement the best solution. By considering the interplay of various contaminants and factors, mining operations can develop targeted and effective treatment strategies to mitigate toxicity and protect the environment. This approach is crucial for ensuring the long-term sustainability of mining operations and minimizing their environmental footprint.