Abstract: The feasibility of fly ash as compared to lime to ameliorate the low pH of acidic coal mine spoils under controlled pot culture conditions are reported using Sudan grass (Sorghum studanens) and Oats (Avena sativa) as indicator crops. It is observed that at all levels of applications, fly ash and lime significantly increase the pH of mine spoils, available phosphorus, exchangeable potassium, available sulphur and also uptake of phosphorus, potassium, sulphur and oven-dried biomass of both these test crops. The fly ash significantly decreases the bulk density of coal mine spoils, but, there is no effect on bulk density due to lime application. However, when the spoils are amended with either fly ash or lime, the root growth occurs throughout the material. Fly ash and lime do not cause elemental toxicities to the plants as evidenced from the dry matter production by the test crops. The results indicate that fly ash to be a potential alternative to lime for treating acidic coal mine spoils.

Abstract: Seven kilometres of the River Pelenna in South Wales were impacted for approximately 30 years by discharges from abandoned coal mines. Elevated iron and low pH caused significant ochreous staining and had detrimental effects on the river ecology. The River Pelenna Mine water project constructed a series of passive wetland treatment systems to treat these discharges. Monitoring of the performance and environmental benefits of these has been undertaken as part of an Environment Agency R&D project. This project has assessed the changes in water quality as well as monitoring populations of invertebrates, fish and birds between 1993 and 2001. Performance data from the wetlands show that on average the three systems are removing between 82 and 95% of the iron loading from the mine waters. In the rivers downstream, the dissolved iron concentration has dropped to below the Environmental Quality Standard (EQS) of 1 mg/L for the majority of the time. Increases in pH downstream of the discharges have also been demonstrated. Trout (Salmo trutta) recovered quickly following mine water treatment, returning the next year to areas that previously had no fish. Intermittent problems with overflows from the treatment systems temporarily depleted the numbers, but the latest data indicate a thriving population. The overflow problems and also background episodes of acidity have affected the recovery of the riverine invertebrates. However, there have been gradual improvements in the catchment, and in the summer of 2001 most sites held faunas which approached those found in unpolluted controls. Recovery of the invertebrate fauna is reflected in marked increases in the breeding success of riverine birds between 1996 and 2001. This study has shown that constructed wetlands can be an effective, low cost and sustainable solution to ecological damage caused by abandoned mine drainage.

Abstract: Mining usually causes severe anthropogenic changes by which the ground- or surface water might be significantly polluted. One of the main problems in the mining industry are acid mine drainage, the drainage of heavy metals, and the prediction of mine water rebound after mine closure. Therefore, the knowledge about the hydraulic behaviour of the mine water within the flooded mine might significantly reduce the costs of mine closure and remediation. In the literature, the difficulties in evaluating the hydrodynamics of flooded mines are well described, but only few tracer tests in flooded mines have been published so far. Most tracer tests linked to mine water problems were related to either pollution of the aquifer or radioactive waste disposal and not the mine water itself. Applying the results of the test provides possibilities f or optimizing the outcome of the source-path-target methodology and therefore diminishes the costs of remediation strategies. Consequently, prior to planning of remediation strategies or numerical simulations, relatively cheap and reliable results for decision making can be obtained via a well conducted tracer test. < copyright > 2005 Elsevier GmbH. All rights reserved.