Abandoned mines are a major mining liability for the state of Minas Gerais, Brazil. The impacts and risks of abandoned mines are specific to the location and type of ore, but they cover social, economic, and cultural aspects. A central element of an abandoned mine management policy is the definition of a methodology to identify and rank characteristics of abandoned mines that pose a risk to the environment and society. This article presents a methodology for the ranking of environmental risks for abandoned mines in the state of Minas Gerais based on different evaluation factors of their external effects on the environment, safety, the population and surrounding areas, heritage and the landscape. The environmental risk of the abandoned mine area was generated to establish the “Abandoned Mine Area Environmental Risk Hierarchy”. To achieve this a multi-criteria analysis (using the Analytical Hierarchy Process (AHP)) was adopted with each preponderant factor being compared and measured. The results show that the use this framework can support in the decision-making process of an environmental agency for developing the intervention aimed at situations of greater gravity, which, ultimately, may require the use of public resources to reduce risks.

Soil contamination by radionuclides, heavy metal, pesticides, among others, threatens ecosystems and human health.Environmental monitoring bodies and agencies need reference values for these contaminants in order to assess the impacts of anthropogenic activities on soil contamination. Quality Reference Values (QRVs) reflect the natural concentrations of contaminants in soils without anthropic interference and must be regionally established. The aim of this study was the determination of natural concentrations and quality reference values for U and Th in soils from Minas Gerais State, Brazil. A large variation of the natural activity concentration of these radionuclides in soil was observed.The QRV for U was 86.5 Bq kg -1 and 90.81 Bq kg -1 for Th. Statistical analysis showed that the two elements have a positive correlation with the clay and organic matter content in soil, and with the soil orders Ultisol and Inceptisol.Uranium shows a strong correlation with As, Sb, Se and Hg, while Thorium does not show correlation with any of the trace elements.

Este artigo apresenta uma avaliação do quadro normativo do Brasil, mais especificamente do Estado de Minas Gerais, quanto ao fechamento de minas e a gestão de minas abandonadas, decorrentes de um fechamento prematuro ou mal planejado. Mina abandonada é uma mina que o processo de fechamento está incompleto ou ausente, com a atividade de extração mineral inativa, sem previsão de reinício da atividade, sem medidas de controle ou monitoramento ambiental implementadas, apresentando características de abandono. A consulta e a análise das principais leis ordinárias e as normas infralegais federais e estaduais, relativas ao meio ambiente e mineração constituíram a base para realização deste estudo, assim como a consulta a banco de dados de minas abandonadas e os processos ambientais do Estado de Minas de Gerais, com visitas às minas para vistoria in loco. O artigo aponta que embora as regulamentações sobre fechamento de mina no Brasil sejam recentes, ocorreram avanços, com o estabelecimento da etapa de fechamento de mina no novo decreto do Código de Minas, no ano de 2018 e a modernização da legislação sobre o tema no Estado de Minas Gerais, neste mesmo ano. Entretanto, o ordenamento legal não está sendo concretizado em uma política pública efetiva pelos órgãos competentes, com a inexistência de um programa para a inibição do surgimento de minas abandonadas ou acompanhamento das minas abandonadas já identificadas.