RESIDUAL SPACE VOLUMES IN ABANDONED COAL MINES OF THE BELGIAN CAMPINE BASIN AND POSSIBILITIES FOR USE
Flemish Institute for Technological Research (Vito), Boeretang 200, B-2400 Mol. E-mail: peter.vantongeren@vito.be
Flemish Institute for Technological Research (Vito), Boeretang 200, B-2400 Mol.. E-mail: roland.dreesen@vito.be
Abstract
The abandoned former coal mines of the Campine basin represent significant, human induced subsurface reservoirs. They consist of two interconnected main parts: the large, mined-out areas of former coal production (panels and most galleries) and the principal infrastructure of stone drifts, shafts, bunker and platform areas. Both main elements have their own flow characteristics due to general differences in porosity and permeability (poro / perm) conditions. The former infrastructure is assumed to have remained largely open. Back-filled and goaf areas of the formerly mined panels contain effective porosities in the order of 3 - 8 %. Their permeability changes from a multi-directional ‘normal’ flow pattern in the centre of the goaf sheet to a more unidirectional, fi ssure-guided (semi-) perpendicular flow pattern, in the outer, surrounding parts. For the former collieries in the Campine basin a total remaining volume of over 35 million m3 has been calculated, roughly situated within the 450 - 1050 m depth interval. Presently these mines are still only partially flooded by rising mine water. To assess the utility possibilities of these former mines, Flanders has engaged into a GIS-mapping program of both former infrastructure and goaf areas of these mines. This allows selection of optimal areas for energy production, like abandoned coal mine methane (ACMM) and / or (enhanced) coalbed methane (ECBM). Geothermal use of, or energy storage in the mine water is feasible as well. Storage of industrial residues, natural gas (methane; CH4) and in some cases even (of limited amounts) of carbon dioxide (CO2) appears feasible too. If (well) prepared before abandonment, the former mines may even be used for production of electricity (water flow in micro-turbines) or geothermal energy (CO2 convection systems).