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Acid mine waters can cause both chemical and microbiological corrosion to mining equipment and other steel and concrete structural elements, such as bridges. Corrosion depends on factors such as pH, dissolved oxygen, the ions present in the water, biological activity, and temperature. The presence of certain bacteria, such as Acidothiobacillus ferrooxidans, increases the acidity of the water and so increases the corrosion rate. Corrosion has been widely studied but is still a difficult and expensive problem and further work is needed to analyse chemical and electrochemical processes at work on mechanical structures exposed to AMD., Acid mine waters can cause both chemical and microbiological corrosion to mining equipment and other steel and concrete structural elements, such as bridges. Corrosion depends on factors such as pH, dissolved oxygen, the ions present in the water, biological activity, and temperature. The presence of certain bacteria, such as Acidothiobacillus ferrooxidans, increases the acidity of the water and so increases the corrosion rate. Corrosion has been widely studied but is still a difficult and expensive problem and further work is needed to analyse chemical and electrochemical processes at work on mechanical structures exposed to AMD.

The aim of this study was to chemically charac- terize the water quality impacts of the 88 acid mine drainage (AMD) generating mines in the Spanish sector of the Iberian Pyrite Belt (IPB). This was necessary because the Water Framework Directive of the European Union and the hydro- logical plans of the Tinto, Odiel, and Piedras river basins require that water quality be improved enough to allow at least some of the rivers in the IPB to sustain healthy fish populations by 2027. The results indicate a clear decrease in metals, arsenic, and sulfate concentrations and increased pH between the AMD-sources and the river channels.

Poderosa Mine is an abandoned pyrite mine, located in the Iberian Pyrite Belt which pours its acid mine drainage (AMD) waters into the Odiel river (South-West Spain). This work focuses on establishing possible reasons for interdependence between the potential redox and pH, with the load of metals and sulfates, as well as a set of variables that define the physical chemistry of the water—conductivity, temperature, TDS, and dissolved oxygen—transported by a channel from Poderosa mine affected by acid mine drainage, through the use of techniques of artificial intelligence: fuzzy logic and data mining. The sampling campaign was carried out in May of 2012. There were a total of 16 sites, the first inside the tunnel and the last at the mouth of the river Odiel, with a distance of approximately 10 m between each pair of measuring stations. While the tools of classical statistics, which are widely used in this context, prove useful for defining proximity ratios between variables based on Pearson’s correlations, in addition to making it easier to handle large volumes of data and producing easier-to-understand graphs, the use of fuzzy logic tools and data mining results in better definition of the variations produced by external stimuli on the set of variables. This tool is adaptable and can be extrapolated to any system polluted by acid mine drainage using simple, intuitive reasoning.

Hydropower is a potential large source of electricity supply in Wales. The Upper River Severn in Mid Wales is a typical stream where a high head hydropower scheme could be developed and the river system at Plynlimon has some of the longest records for weather and flow in Wales. A micro-hydropower potential of 99 kW is demonstrated at Plynlimon and the potential impacts of climate change are simulated to assess the effects on flows and power outputs of such schemes under climate uncertainty. Based on UK Climate Projections 2009 (UKCP09) projections, the impacts of climate change are to significantly decrease both the stream flows and energy production during summer months but to increase flows and power production in the winter, with a net tendency to cancel out over the course of a full year. A methodology for assessing impacts of climate change on hydropower is established, which could be applied more widely to other potential hydropower sites such as lowland rivers or high base flow rivers in other parts of the UK. This will be useful for developers, water companies and environmental agencies to assess hydropower potential, economic viability and environmental impacts of micro-hydropower, under future climate change.

pH and chlorinity content of estuarine water and behavior in the concentration of some heavy metals characteristics of acid mine drainage in the suspended matter and dissolved phase have allowed the identification of two mixing process in the Odiel-Tinto rivers estuary: a salt-induced mixing typical of marine estuaries and an acid neutralization process as a result of the mixture of acid fluvial water coming from the drainage basins, which are affected by acid mine drainage (AMD). Thus, the estuary is divided into three zones: (1) zone with acid water and with precipitation of sulphate phases during the beginning of the process of neutralization in the absence of salt-induced mixing, (2) zone with pH values between 4.5 and 7 where a removal of heavy metals in their dissolved phase is produced by coexistence of both mixture processes, and (3) zone where water is slightly basic and the salt-induced mixing produces a redissolution of some elements. Spatial location and extent of these zones within the estuarine system have seasonal variations depending on the volume of fluvial discharge.

The Iberian pyrite belt is a metallogenic province with many abandoned mines, though Cobre las Cruces and Aguas Tenidas are still operating and others may reopen; the magnitude and ubiquity of their discharges make the belt a unique source of acid mine drainage (AMD) generation. The water quality impacts of the 88 AMD-generating mines in the Spanish sector of the belt were chemically characterised under EU and more local requirements that water quality be improved enough for at least some rivers in the belt to sustain healthy fish populations by 2027. The results indicate a clear decrease in metal, As and SO4 concentrations and increased pH between the sources of acid mine drainage and the river channels., The Iberian pyrite belt is a metallogenic province with many abandoned mines, though Cobre las Cruces and Aguas Tenidas are still operating and others may reopen; the magnitude and ubiquity of their discharges make the belt a unique source of acid mine drainage (AMD) generation. The water quality impacts of the 88 AMD-generating mines in the Spanish sector of the belt were chemically characterised under EU and more local requirements that water quality be improved enough for at least some rivers in the belt to sustain healthy fish populations by 2027. The results indicate a clear decrease in metal, As and SO4 concentrations and increased pH between the sources of acid mine drainage and the river channels.

The degree of pollution in 23 reservoirs in the semi-arid Iberian pyrite belt in southwest Spain has been investigated along the basins of the Tinto and Odiel rivers, the main water courses affected by acid mine drainage (AMD), and the Chanza and Guadiamar rivers . The reservoirs all exceeded the limits established by EEC directive 75/440 for Mn, Cd and Pb, 96% of the reservoirs were above the limit laid down for Fe, and 87% of the reservoirs exceeded the Al limit. The lowest pH values, the highest measured average values for electrical conductivity and total dissolved solids, and the highest metal and sulphate concentrations were determined in the eight reservoirs that were most affected by acid mine drainage. The degree of pollution in the waters stored in the reservoirs is assessed and the development of a regional risk map of the overall extent of the problem described., The degree of pollution in 23 reservoirs in the semi-arid Iberian pyrite belt in southwest Spain has been investigated along the basins of the Tinto and Odiel rivers, the main water courses affected by acid mine drainage (AMD), and the Chanza and Guadiamar rivers . The reservoirs all exceeded the limits established by EEC directive 75/440 for Mn, Cd and Pb, 96% of the reservoirs were above the limit laid down for Fe, and 87% of the reservoirs exceeded the Al limit. The lowest pH values, the highest measured average values for electrical conductivity and total dissolved solids, and the highest metal and sulphate concentrations were determined in the eight reservoirs that were most affected by acid mine drainage. The degree of pollution in the waters stored in the reservoirs is assessed and the development of a regional risk map of the overall extent of the problem described.

An adaptive neuro-fuzzy inference system (ANFIS) was developed to model an acid mine drainage (AMD)-affected river. The inference system uses three relatively expeditious AMD indicators (pH, electrical conductivity and sulphate) and gives asa response concentration values for Fe, Mn, Cu, Zn, Cd, and As. It was based on a large database, which resulted from monitoring the Chorrito stream, an AMD stream which flows into the Cobica river in the Iberian Pyrite Belt, SW Spain. The results indicate a high correlation between the analysed values and the concentrations obtained by fuzzy estimation. Therefore, this modelling approach affords a simple and cost-effective system capable of monitoring the affected river, since it avoids or simplifies the analysis of the most expensive and time-consuming chemical parameters., An adaptive neuro-fuzzy inference system (ANFIS) was developed to model an acid mine drainage (AMD)-affected river. The inference system uses three relatively expeditious AMD indicators (pH, electrical conductivity and sulphate) and gives asa response concentration values for Fe, Mn, Cu, Zn, Cd, and As. It was based on a large database, which resulted from monitoring the Chorrito stream, an AMD stream which flows into the Cobica river in the Iberian Pyrite Belt, SW Spain. The results indicate a high correlation between the analysed values and the concentrations obtained by fuzzy estimation. Therefore, this modelling approach affords a simple and cost-effective system capable of monitoring the affected river, since it avoids or simplifies the analysis of the most expensive and time-consuming chemical parameters.

The Tinto and Odiel river basins drain the volcanogenic massive sulphide deposits of the Iberian Pyrite Belt and water from the estuaries flows into the northwest of the Gulf of Cadiz. The effect of seawater dilution and acid neutralisation on REE fractionation was investigated based on analysis of sediment samples from traps placed along the estuaries. The REE fractionation in the sediments could be grouped into three North American Shale Composite (NASC) normalised patterns depending on the environmental conditions prevailing in the areas where they were deposited. Fluvial estuarine sediments deposited at pH less than 4 and Cl concentrations below 2 g/l showed a slightly middle REE-enriched NASC normalised pattern. The estuarine mixing zone involves steep gradients characterised by pH values of 5-7 and chlorinity of 2-10 g/l and under these conditions the sediments exhibited light REE depletion and an almost flat trend for middle and high REE. Once acid neutralisation was finished at the outer estuary the pH increased to more than 7 and the chlorinity to above 10 g/l and the sediments showed a light and medium REE enriched pattern with a slightly negative La anomaly typical of marine conditions. The close relationship between pH and REE content indicates that pH is a key variable controlling REE geochemistry in estuarine systems affected by acid mine drainage., The Tinto and Odiel river basins drain the volcanogenic massive sulphide deposits of the Iberian Pyrite Belt and water from the estuaries flows into the northwest of the Gulf of Cadiz. The effect of seawater dilution and acid neutralisation on REE fractionation was investigated based on analysis of sediment samples from traps placed along the estuaries. The REE fractionation in the sediments could be grouped into three North American Shale Composite (NASC) normalised patterns depending on the environmental conditions prevailing in the areas where they were deposited. Fluvial estuarine sediments deposited at pH less than 4 and Cl concentrations below 2 g/l showed a slightly middle REE-enriched NASC normalised pattern. The estuarine mixing zone involves steep gradients characterised by pH values of 5-7 and chlorinity of 2-10 g/l and under these conditions the sediments exhibited light REE depletion and an almost flat trend for middle and high REE. Once acid neutralisation was finished at the outer estuary the pH increased to more than 7 and the chlorinity to above 10 g/l and the sediments showed a light and medium REE enriched pattern with a slightly negative La anomaly typical of marine conditions. The close relationship between pH and REE content indicates that pH is a key variable controlling REE geochemistry in estuarine systems affected by acid mine drainage.