Postmining management in france: situation and perspectives

Groundwater Risk Assessment in the Context of an Underground Coal Mine Closure and an Economic Evaluation of Proposed Treatments: A Case Study

Mining companies are responsible for the impacts that result from their mining activities even after the mining period has ended. At the same time, at the European and international levels, there is a lack of a detailed operational methodology comprising environmental risks during and after closure of underground coal mines. The environmental risk aspects that need to be considered when planning the closure of an underground coal mine and post closure in the broader environmental context are the following: modification of water flow scheme, surface instability, mine gas emission on the surface, and water and soil pollution. In this study, we focus on assessing groundwater risk in the context of an underground coal mine closure and evaluating the selected risk mitigation strategies in terms of performance and cost. The results from this study could be used for developing a final closure groundwater assessment plan by selecting the most feasible treatment alternatives for different environmental impacts, together with the transitional monitoring that could guarantee a hazard level in compliance with land reuse and the use of natural resources. Finally, the cost-efficient monitoring and treatment programs are used to estimate the financial provisions needed to mitigate groundwater risks during underground coal mine closure contexts.

Environmental and Safety Risks Related to Methane Emissions in Underground Coal Mine Closure Processes

The closure process of underground coal mines entails specific risks which require a careful liquidation methodology, including the implementation of relevant risk mitigation procedures to identify the key hazards to the environment and humans. As gas represents one of the major risks, it needs to be taken into consideration in the liquidation process. Given its adverse effect on the environment, methane, a greenhouse gas, requires particular attention and may also reach dangerous concentrations in the ground floor areas and basements of buildings as well as in areas where mine closure works are conducted, leading to intoxication, asphyxia or explosions. This paper presents a risk analysis of the methane hazard occurring at the final stage of the closure process of a Polish underground mine. It applies a methane emission model created jointly by the National Institute for the Environment and Industrial Hazards (INERIS) in France and the Central Mining Institute (GIG) in Poland. The analyses and measurements carried out for this paper were conducted within the framework of the Management of Environmental Risks during and after Mine Closure (MERIDA) project. The subject of the study included: the flooding process and how it affects the scale of gas emission from goafs, changes in methane concentration, and changes in the volume of voids.

Trace metals from historical mining sites and past metallurgical activity remain bioavailable to wildlife today

Throughout history, ancient human societies exploited mineral resources all over the world, even in areas that are now protected and considered to be relatively pristine. Here, we show that past mining still has an impact on wildlife in some French protected areas. We measured cadmium, copper, lead, and zinc concentrations in topsoils and wood mouse kidneys from sites located in the Cévennes and the Morvan. The maximum levels of metals in these topsoils are one or two orders of magnitude greater than their commonly reported mean values in European topsoils. The transfer to biota was effective, as the lead concentration (and to a lesser extent, cadmium) in wood mouse kidneys increased with soil concentration, unlike copper and zinc, providing direct evidence that lead emitted in the environment several centuries ago is still bioavailable to free-ranging mammals. The negative correlation between kidney lead concentration and animal body condition suggests that historical mining activity may continue to play a role in the complex relationships between trace metal pollution and body indices. Ancient mining sites could therefore be used to assess the long-term fate of trace metals in soils and the subsequent risks to human health and the environment.