Influence of mine hydrogeology on mine water discharge chemistry

Abstract

Using data for 81 coal mine discharges in the UK, the influence of discharge hydrogeology on discharge chemistry is assessed and typical chemical parameters derived for five discharge types. A combination of modified and new classification schemes is used to differentiate between the various discharge sources. Drainage from spoil tips generally has a pH below 5 and net-alkalinity values as low as — 2500 mg l−1 CaCO3. Drainage from flooded workings and pumped discharges are net-alkaline, while drainage from flooded and free draining workings are either moderately net-alkaline or net-acidic. Iron is the major contaminant of concern, although many mine waters contain less than 30 mg l−1 and Fe/SO4 ratios are less than unity. The classification schemes developed can be used to assess mine water treatment requirements and processes operating in passive treatment systems.

Contemporary Reviews of Mine Water Studies in Europe, Part 1

“…Responsibility for treatment of such discharges ordinarily lies with the landowner. Novel passive treatment systems have been installed at some of these sites due to their more acidic nature (Rees et al 2002). For example, the first compost wetland in Europe was installed at Quaking Houses, County Durham, in 1997 (see Jarvis and Younger, 1999).…”

Mining Impacts on the Fresh Water Environment: Technical and Managerial Guidelines for Catchment Scale Management

“…In this diagram the alkalinity-acidity balance defines one axis of a 2-D plotting field, while the other axis uses a general indicator of mine water provenance, manifested in the balance between SO 4 2-(generally representing the degree of pyrite oxidation) and Cl -(elevated concentrations generally indicating ancient sedimentary waters). This diagrammatic format has been recently improved by Rees et al (2002), by plotting the alkalinity/acidity balance in terms of the overall "net alkalinity", which equals the total alkalinity minus the total acidity ( Figure 18). …”

“…Figure 18. Mine water classification diagram in terms of net alkalinity and proportions of chloride to sulphate, following the scheme of Younger (1995) adapted in accordance with the proposals of Rees et al (2002) Appendix II…”

“…Land Contamination and Reclamation, Hedin RS, Nairn RW, Kleinmann RLP (1994) water management questions in the planning for the long-term fate, remediation and mine water pollution abatement of mine tailings and waste rock. The negotiations are required because there may exist different interpretations and relevance evaluations of the scientific analysis (dynamic problem characterisation and abatement measure optimisation), the legislation, and the political decisions and interests that determine the answers to the key water management questions 42 14 Schematic illustration of dynamic characterisation of the water pollution problem, using the Environmental Information System, consisting of the entire set of available (to some or all stakeholders) relevant information about this problem, including recent and historic monitoring data, as well other types of information and information systems, such as basic geomorphologic, hydrologic and hydrogeologic data, socioeconomic data on water, land and geologic uses and potential pollution sources, modelling tools for data and information interpretation and extrapolation, and technological feasibility and cost data 43 15 Example of a V-notch weir measuring the overflow from the Blaydon Hazard Shaft, an abandoned coal mine near Newcastle upon Tyne, UK 47 16 Example of a standard box-plot showing 312 data points at 17 mine water sampling points (Wolkersdorfer 1996) 50 17 Example of a histogram, showing the frequency distribution of Sb and the clustering of the data 51 18 Mine water classification diagram in terms of net alkalinity and proportions of chloride to sulphate, following the scheme of Younger (1995) adapted in accordance with the proposals of Rees et al (2002) 52 19 Flowchart giving the basic decision-making logic for the selection of the most appropriate remedial option for a polluting mine water discharge (after Younger 2002a). Note that this flowchart proposes no final endpoint for all activities, because precautionary monitoring (even if only by visual inspection) will nearly always be advisable 55 20 Suitability of monitored natural attenuation, passive treatment and active treatment options for remediation of polluted mine waters, expressed as functions of the magnitude of flow and intensity of contamination of mine water discharges (after Younger 2002a) 56 21 Schematic illustration of the two different economic decision rules: a) maximisation of total net benefits, i.e.…”

Flow dependent water quality impacts of historic coal and oil shale mining in the Almond River catchment, Scotland

“…Waste rock brought to the surface in the process of mining can also produce similar mine waters, via pyrite oxidation, on exposure to atmospheric oxygen and precipitation (Bell, 1996;Banks et al 1997b;Rees et al, 2002;Lottermoser 2010;Nordstrom, 2011). When discharged at the surface mine waters can have serious environmental consequences for water quality in recipient streams and rivers (Younger, 1995;Banks et al, 1997a, Jarvis & Younger 1997.…”