Coalfield closure and the water environment in Europe

Abstract

Some of the negative consequences that coalfield closure can have for the water environment are now well documented in Western Europe, providing a useful check-list for possible eventualities during the restructuring of the coal industry in Eastern Europe. As individual mines have closed over the years the burden of dewatering has been passed on to ever fewer remaining collieries, until the last working mines in a coalfield may have to carry economically insupportable pumping rates - approaching 15 t of water pumped from the workings for every tonne of coal raised. The final closure of an entire coalfield is usually accompanied by the termination of decades (or even centuries) of regional-scale dewatering, which can have diverse consequences, including: (i) relief from some of the negative side-effects of dewatering, such as where the dewatering effluents were too saline for costeffective treatment prior to disposal; (ii) loss of some former benefits of dewatering, such as the dilution of other surface water pollutants by mixing with less contaminated dewatering effluents; (iii) flooding of the mine workings and surrounding strata, possibly causing geotechnical problems, such as accelerated mine gas emissions and/or renewed subsidence; and (iv) discharge of water from the flooded workings to adjoining surface and subsurface water bodies, which can cause localized surface flooding and (if the mine water is of poor quality) aquatic pollution. As more and more European coalfields are closing European Commission research projects are now addressing some of the more pressing of the above issues, such as the need to develop long-term, low-cost methods for the remediation of mine-water pollution (see www.piramid.org) and the development of environmental regulation strategies for mine waters that take full cognizance of the social and economic needs of both EU member states and accession countries (see www.minewater.net/ermite).