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Title: A survey of ferruginous minewater impacts in the Welsh coalfields
Author: Darren Butler
Author: Martin Mills
Author: Gillian Davies
Author: Gillian Bourn
Author: Doryn Foolchand
Document Type: Monograph
Ferruginous minewater discharges from abandoned coal mines in the South and North Wales coalfields have been causing problems to receiving watercourses for many years (eg. Pelenna catchment). The rapid contraction of coal mining in the South Wales coalfield resulted in the closure of many of the remaining pits during the 1980s, leaving Tower colliery, near Aberdare, and Bettws colliery, near Ammanford, the last remaining deep mines in South Wales. The spate of mine closures, in recent years, has resulted in several new ferruginous discharges to a number of rivers, particularly in the eastern area of the coalfield and the effects of these discharges on the aquatic environment are of growing public concern (eg. R. Rhymney at Hengoed). Though the problem of ferruginous minewater discharges is well documented, the true extent of the problem in the Welsh region of the NRA was unknown prior to this study. The aims of this survey were to locate all ferruginous discharges within the coalfield areas and to assess their impact upon receiving watercourses. The project was carried out in two stages. The first stage of the assessment of all minewaters involved analysis of the discharges and the receiving watercourse for iron, aluminium, suspended solids, pH, dissolved oxygen, conductivity, sulphate and temperature. Visual assessments of the area of river bed affected by iron hydroxide (ochre) deposition, the level of deposition and physical characteristics of the receiving watercourse, such as flow and width, were also made at sites affected by discharges.
Publisher: National Rivers Authority
Publication Date: 1994
Publication Place: Cardiff
Subject Keywords: Water pollutionSurveysMiningCoal byproductsIron
Geographic Keywords: WalesSouth East Valleys
Extent: 40; + appendices
Total file downloads: 72

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