Carbon dioxide sequestration by mines: implications for climate change

Abstract

Anthropogenic activities contribute significantly to the increase in greenhouse gases in the atmosphere, leading to global warming and climate change. Emissions of carbon dioxide (CO2) during ore extraction and beneficiation processes are known to play a substantial role. However, mining waste and abandoned mines have the capacity to sequester CO2 from the atmosphere, which could be a sustainable solution to mitigate climate change. The present review is intended to facilitate an understanding of the factors affecting CO2 sequestration by mining waste and its feasibility at a global scale. The process of mineral carbonation, which itself generates CO2 and contributes to climate change, is a slow process, and pretreatment (mechanical, chemical and thermal) is required to enhance the reaction kinetics, but it increases the implementation cost. However, mineral carbonation is also a sustainable approach to achieve reclamation of mining sites and to immobilize heavy metals in leachate. Life cycle assessment studies have excluded mineral carbonation and include only environmental risks and impacts due to mines. Mining waste is generated in huge quantities, and its potential to sequester CO2 from the atmosphere should be encouraged for its application at an industrial scale. Further research is needed to explore the economic and technical feasibility of using mining waste to reduce atmospheric CO2 content at a global level.