Tracer Tests in flooded underground mines
Tracer tests are a common means to investigate the hydrogeological conditions in the hydrosphere. Nevertheless, only few successful tracer tests in flooded underground mines have been described. In two flooded German underground mines tracer tests with club moss spores (Lycopodium clavatum) and microspheres had been conducted by the use of the LydiA technique. Both times, effective velocities between 1 and 8 m min could be calculated and a good hydraulic connection between the mines’ parts investigated could be proved. Lycopodium Apparatus (LydiA)
Tracing Ground‐Water Movement in Abandoned Coal Mined Aquifers Using Fluorescent Dyes
In shallow, essentially free-draining abandoned coal mine workings, quantitative ground-water tracing using the orange fluorescent dye Sulpho Rhodamine B (CI 45100) provides a powerful hydrogeological tool for determining ground-water flow regimes. However, this is not the case in deep, confined, abandoned coal mine workings where various dyes exhibit a nonconservative behavior due to adsorption onto ferric hydroxide deposits. This is a more significant problem than that of the effects of pH or acidity on fluorescence. Laboratory tests indicate that dyes with sulphonic functional groups should be selected in such situations and that dye concentrations need to be maintained at the highest level commensurate with aesthetic and toxicological conditions.
Groundwater management problems in abandoned coal-mined aquifers: a case study of the Forest of Dean, England
Summary An examination has been made of groundwater related problems experienced in the Forest of Dean since abandonment of the major collieries in 1965. Careful planning prior to abandonment of collieries can reduce the number of poor quality discharges, and so substantially limit surface water pollution. Small-scale mining activity continuing after major colleries have been abandoned can have a serious hydrogeological effect by removal of in situ coal from drainage barriers designed to promote free drainage of the mines. In association with the deterioration of lined river channels which retard surface water infiltration, this disruption of subsurface can result in a drainage significant loss of summer base-flow from surface rivers. Two case histories show that safe disposal of wastes to voids in mined Coal Measures aquifers is possible. Prediction of the hydrogeological behaviour of the mined aquifer is, however, difficult because of the possibility of unrecorded workings, random collapse and associated ponding, and uncertainty over the hydrological behaviour of the coal barriers. Direct investigation of the groundwater flow regime using boreholes and water tracing techniques is recommended.