Mine closure has become an integral part of mine planning in order to mitigate post-closure financial, social and environmental risks to ensure the sustainable closure of mines. Including mine closure considerations into short and long-term mine planning reduces the end of life of mine closure liabilities. Open cast mining activities will ultimately result in a final mine void which, over time, fills with water and forms a pitlake. Pitlakes are becoming increasingly more acceptable forms of mine closure, provided that long term environmental risks can be mitigated. In addition, pitlakes may negate rehabilitation costs associated with backfilling of the final mine void, potential long term water treatment costs and associated carbon emissions.

The paper discusses case studies for mine closure using pitlakes in coal, diamond, manganese and chrome mines in South Africa.

Asturias was historically the second largest producer of mercury in Spain, following Almadén, and by the end of the 1960s, it accounted for 5% of the world’s mercury production. However, a sharp decline in mercury prices led to the gradual closure of all the mines, with the last one, La Soterraña, ceasing operations in 1974. This intense mining activity has left numerous remains of old mines scattered throughout the region, including mine entrances, dumps, piles, and abandoned installations. In the specific case of mercury mines, most of these sites are classified as ‘orphan mines’ due to their abandonment.

It can be observed that virtually all mercury mineralisations in Asturias exhibit a significant geochemical anomaly for arsenic. This element was also historically exploited as a by-product, resulting in the contamination of the tailings. These mines currently present a considerable environmental concern due to the aforementioned contamination. In this study, geochemical modelling was employed as an effective tool to predict the distribution of species in water, primarily focusing on arsenic, and to identify potential arsenic precipitation phases.

The distribution of these deposits is categorised into four districts: Somiedo, Central Carboniferous Basin, Beleño-Ribadesella, and Picos de Europa. With the exception of the deposits in the latter district, which possess distinctive characteristics, the genesis and characteristics of all the deposits are similar. They are associated with fractures, folds, and thrusts affecting Paleozoic materials and are embedded in carbonate materials.

The combination of geochemical modelling and meteorological analysis provides a deeper understanding of the mechanisms behind arsenic mobilisation, which is crucial for the design of effective decontamination strategies. The processes that govern arsenic distribution and precipitation can be better understood by elucidating these mechanisms by this study, contributing to the development of effective remediation efforts aimed at mitigating the environmental impact of historical mining activities in Asturias. The insights gained from this research are essential for informing future policies and practices in environmental management and mine reclamation

Mining has been a traditional economic activity in the province of Córdoba, in the north of Colombia, representing in average 1.83% GDP of the region and producing over US$4.920 million in annual royalties for the country. Nickel, coal, gold, limestone, clays and building materials are resourced, and there are great expectations to produce copper. It faces, however, critical environmental challenges, particularly in water management, due to inadequate regulatory frameworks and the rise of informal mining activities. This study analyzes environmental licenses issued in Córdoba over the past two years by the regional environmental bodies, focusing on coal and building materials extraction, to assess compliance with national and international standards. The findings reveal significant gaps in Colombia’s regulatory framework, especially in water management, compared to global best practices outlined by organizations such as the International Council on Mining and Metals (ICMM) and the Asia-Pacific Economic Cooperation (APEC).

Key deficiencies include the lack of detailed strategies for water resource monitoring, prevention of acid mine drainage (AMD), and long-term water quality protection. Current closure plans often fail to incorporate site-specific water monitoring, such as tracking pH levels, heavy metal concentrations, and total dissolved solids, which are crucial for early contamination detection. Additionally, the absence of robust financial assurances and climate change adaptation measures further exacerbate the risks of long-term environmental liabilities.

The study highlights the need for Colombia to align its regulatory framework with international standards, emphasizing integrated water management, stakeholder engagement, and post-closure monitoring. Addressing these gaps is essential for ensuring sustainable mining practices, mitigating environmental and social risks, and safeguarding water resources in mining regions like Córdoba. The findings underscore the importance of adopting global best practices to enhance environmental stewardship and achieve long-term ecological rehabilitation in Colombia’s mining sector.

Keywords: Mine closure practices, water management, community engagement, socioeconomic effects, Colombia.