Ye, Z. H., Whiting, S. N., Qian, J. H., Lytle, C. M., Lin, Z. Q., & Terry, N. (2001). Trace element removal from coal ash leachate by a 10-year-old constructed wetland. J. Environ. Qual., 30(5), 1710–1719.
Abstract: This study investigated the ability of a 10-yr-old constructed wetland to treat metal-contaminated leachate emanating from a coal ash pile at the Widows Creek electric utility, Alabama (USA). The two vegetated cells, which were dominated by cattail (Typha latifolia L.) and soft rush (Juncus effusus L.), were very effective at removing Fe and Cd from the wastewater, but less efficient for Zn, S, B, and Mn. The concentrations were decreased by up to 99% for Fe, 91% for Cd, 63% for Zn, 61% for S, 58% for Mn, and 50% for B. Higher pH levels (>6) in standing water substantially improved the removing efficiency of the wetland for Mn only. The belowground tissues of both cattail and soft rush had high concentrations of all elements; only for Mn, however, did the concentration in the shoots exceed those in the belowground tissues. The concentrations of trace elements in fallen litter were higher than in the living shoots, but lower than in the belowground tissues. ne trace element accumulation in the plants accounted for less than 2.5% of the annual loading of each trace element into the wetland. The sediments were the primary sinks for the elements removed from the wastewater. Except for Mn, the concentrations of trace elements in the upper layer (0-5 cm) of the sediment profile tended to be higher than the lower layers (5-10 and 10-15 cm). We conclude that constructed wetlands are still able to efficiently remove metals in the long term (i.e., >10 yr after construction).
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Bennett, J. W., Timms, G. P., & Ritchie, A. I. M. (1999). The effectiveness of the covers on waste rock dumps at Rum Jungle and the impact in the long term. Mining into the next century : environmental opportunities and challenges Proceedings of the 24th annual environmental workshop Townsville October, , 379–388.
Abstract: Covers are widely used as a means of controlling pollutant generation from sulfidic waste piles. To date, there has been little data available to test the effectiveness of such covers. Monitoring of two waste rock dumps at Rum Jungle over more than fifteen years has provided the opportunity to assess cover effectiveness in the medium term. For the first 9 years the infiltration rate through the cover on Whites dump was less than the design figure of 5 per cent of rainfall. In subsequent years, however, the rate has increased to between 5 and 10 per cent. In the first six years the infiltration rate through the cover on Intermediate dump was also less than 5 per cent. Unfortunately, further measurements had to be abandoned due to equipment malfunction in this dump. Oxygen and temperature profiles measured below the cover have been used to estimate the overall oxidation rate in the two dumps. This is between 30 and 50 per cent of the oxidation rate prior to installation of the cover. The effect these results have on pollutant loads in drainage in the long term depends on the nature of the control mechanisms in the system. If pollutant concentrations in drainage are determined by secondary mineralisation within the dumps then pollutant loads in the long term will be essentially proportional to any further increase in the infiltration rate. If the pollutant loads in drainage are largely determined by the overall oxidation rates then we can expect the pollutant loads from the two dumps to increase in the long term to a level about one third to one half of that prior to rehabilitation. In this context, 'long term' means about 40 years after installation of the cover system. Given the implications this work has for the use of soil covers, the following additional studies should be undertaken: A measurement program to quantify the pollution loads from Intermediate and Whites waste rock dumps. A program of computation, backed by acquisition of mineralogical data on the wastes, to address the question of controls on concentration and load in effluent from the two dumps. A program to determine the reason for the deteriorating performance of the covers at Rum Jungle.
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Coulton, R., Bullen, C., & Hallett, C. (2003). The design and optimisation of active mine water treatment plants. Land Contam. Reclam., 11(2), 273–280.
Abstract: This paper provides a 'state of the art' overview of active mine water treatment. The paper discusses the process and reagent selection options commonly available to the designer of an active mine water treatment plant. Comparisons are made between each of these options, based on technical and financial criteria. The various different treatment technologies available are reviewed and comparisons made between conventional precipitation (using hydroxides, sulphides and carbonates), high density sludge processes and super-saturation precipitation. The selection of reagents (quick lime, slaked lime, sodium hydroxide, sodium carbonate, magnesium hydroxide, and proprietary chemicals) is considered and a comparison made on the basis of reagent cost, ease of use, final effluent quality and sludge settling criteria. The choice of oxidising agent (air, pure oxygen, peroxide, etc.) for conversion of ferrous to ferric iron is also considered. Whole life costs comparisons (capital, operational and decommissioning) are made between conventional hydroxide precipitation and the high density sludge process, based on the actual treatment requirements for four different mine waters.
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Banks, S. B. (2003). The Coal Authority Minewater Treatment Programme: An update on the performance of operational schemes. Land Contam. Reclam., 11(2), 161–164.
Abstract: The performance of mine water treatment schemes, operated under the Coal Authority's national Minewater Treatment Programme, is summarised. Most schemes for which data are available perform successfully and remove over 90% iron. Mean area-adjusted iron removal rates for reedbed components of treatment schemes, range from 1.5 to 5.5 g Fe/m2, with percentage iron removal rates ranging from 68% to 99%. In the majority of cases, calculated area-adjusted removal rates are limited by influent iron loadings, and the empirical sizing criterion for aerobic wetlands, based on American removal rates of 10 g Fe/m2day, remains a valuable tool in the initial stages of treatment system design and estimation of land area requirements. Where a number of schemes have required modification after becoming operational, due consideration must always be given to the potential for dramatic increases in influent iron loadings, and to how the balance between performance efficiency and aesthetic appearance can best be achieved. Continual review and feedback on the performance of treatment systems, and the problems encountered during design implementation, will enhance the efficiency and effectiveness of the Minewater Treatment Programme within the UK.
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Ballivy, G., & Bienvenu, L. (1998). Stabilisation des rejets miniers a l'aide de rejets de cimenterie. Stabilization of mining wastes using cement factory wastes Activites de recherche du Ministere des Ressources Naturelles du Quebec sur le drainage minier acide; rapport 1997-1998. Research activities of the Quebec Natural Resources Ministry on acid mine drainage; report 1997-1998 (Vol. Rn 98-5034).
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