Pires, AB & Weber, CC 2023, 'From coal mine to sanitary landfill: The rehabilitation of Recreio Mine in Butiá, Brazil ', in B Abbasi, J Parshley, A Fourie & M Tibbett (eds), Mine Closure 2023: Proceedings of the 16th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, https://doi.org/10.36487/ACG_repo/2315_097
(https://papers.acg.uwa.edu.au/p/2315_097_Pires/)
Abstract: The Recreio mine was a coal mine located in the metropolitan region of Porto Alegre (state of Rio Grande do Sul, Brazil – RS/BR) that began operations in the 1970s by Copelmi Mining Ltd. At that time, environmental concerns were minimal in Brazil, and environmental legislation was practically non-existent. Under this context, the mine operated and generated an environmental liability corresponding to a pit of more than 100 hectares of surface disturbance at the end of its life cycle in 1990. In 1988, the new Brazilian Federal Constitution (CFB/88) came into force, explicitly determining that those who exploit mineral resources are now obliged to reclaim the environment degraded by their activity. At that same time, discussions about the prohibition of uncontrolled disposal of municipal solid waste (MSW) in dumps were gaining strength due to the accident that occurred in 1987 with the inadequate disposal of Cesium-137 in a dump, resulting in the contamination of 249 people and 4 deaths. In 1990, the entire metropolitan region of Porto Alegre still deposited its MSW irregularly in dumps and would need to adapt to the norms for the final disposal of its waste. Likewise, Copelmi would need to rehabilitate the Recreio mine under the terms of CFB/88. Considering this statutory scenario, the proximity between the Recreio mine and the municipalities with the highest MSW sanitary generation (90 km), the available volume in the mine final pit (30 million m³), the favourable geological and hydrogeological characteristics of the Recreio mine for controlled disposal of MSW, and, that the construction of a sanitary landfill on previously undisturbed land is an activity that degrades the environment, in 1990, Copelmi (Research and Mineral Mining Company) identified the opportunity to rehabilitate the final pit of the Recreio mine through the construction of a sanitary landfill on the site, named Aterro Sanitário de Minas do Leão (ASML). The sanitary landfill (ASML) received its first environmental permit in 1996. As of 2001, it began to dispose of MSW generated by 35% of the population of the state of RS/BR. Currently, ASML has a daily capacity to receive 120,000 tons of MSW and serves 39% of the population of RS/BR. Since 2007, ASML has been generating carbon credits by destroying gases in a flare and, since 2015, biogas has been fed to six generators that deliver up to eight MWh of electricity to the regulated energy market.

Keywords: coal mining, municipal urban waste, landfill, asset repurposing, statutory compliance