Multi-hazard analysis of abandoned coal-mines

Nowadays, most of the coal mines in Europe are already closed or are in a state of liquidation. However, the problem of abandoned coal mines and their influence on the environment remains central for the mining industry and coal regions in transition. After the end of the exploitation, many disturbances can occur. Mines operators, local authorities and decision makers are confronted with multi-hazard and risks related to mine closure. Land use planning and adequate site rehabilitation requires better tools to deal with the multiple hazards and constraints.

The objective of the study is to improve risk assessment by establishing a new methodology to assess the interaction between hazards related to old mines, and no longer treat them separately.

Mining hazards concern: ground movements, hydrological hazards, self-heating, soil and water pollution. One hazard can trigger another one. Different tools are presented such as a global matrix, a fault tree, etc. for identifying the hazards interaction. The hazard interaction matrix has been constructed, figure 1 shows in particular the interactions that the phenomena in the columns (source phenomenon) can have with the phenomena in the rows (target phenomenon). The matrix also provides information on the levels of interaction: no known case of interaction between phenomena (white colour), Low (yellow), Medium (green) and High (red). These assessments are based on feedback and in-depth discussion between experts. This approach is a first tool to help mining and development actors to understand these interactions and improve mitigation and management measures.