The restoration of colliery wastes and open pit coal sites in the United Kingdom (UK) is undertaken according to a land use strategy plan and detailed specifications that have been agreed upon with the planning authorities.For two of the major land uses in the UK, agriculture and forestry, data on physical criteria (climate, site features and soils) are available to assist in the planning and design of land use strategies and specification of restoration treatments. Similar criteria could also be developed for the restoration of semi natural vegetation and habitats for landscape, wildlife, and amenity uses.Three examples are described illustrating the use of the physical criteria in the design of schemes, the specification of treatments, and the assessment of achievements. AdditionalWhy Criteria?The restoration of colliery lagoons and spoil heaps, and of open pit coal sites in the UK is undertaken according to a land use strategy plan and detailed specifications. These are usually prepared by the industry in conjunction with consultants. The restoration plan shows the location and types of land use and is accompanied by detailed specifications for all aspects of the treatment and management work to be used to achieve the strategy. Both the strategy and the specifications have to be agreed upon with the local government planning authorities. Usually the strategy is agreed upon during early consultations and the application stage of the process. In long-term developments, the principles of the strategy may be outlined and, by agreement, modified according to changes in local and national land use policies. The details of the specifications may be agreed upon at the same time or delayed until just before restoration commences.
Broadleaved woodland is an important land use and vegetation• type in the United Kingdom (UK), and potentially the most effective landscape and restoration treatment for colliery waste tips and open pit coal sites.A field-based national survey of collieries in England and Wales in 1986 and 1987 showed that establishment was satisfactory in only half of the schemes, and growth was deemed satisfactory in less than one-fifth. Also, the majority of the plantations had little affinity with woodland types found locally or regionally. The main causes of poor establishment were poor stock viability, and competition with herbaceous ground cover vegetation for available soil water in the immediate post planting period. The poor growth was due to competition for water with herbaceous vegetation and low inherent available water capacity of the soil profiles.There are standard forestry practices whereby stock quality can be assured, and herbaceous vegetation controlled or eliminated by the use of herbicides. During the restoration of the site, depending on choice of species, adequate soil water can be provided by the selection of appropriate soil types and thicknesses, and adoption of appropriate soil handling and decompaction practices. The low affinity of the plantations with local and regional types was partly due to the planting of non native species and partly due to the failure to match species with site and soil characteristics. There is no reason why woodlands of a local and regional character cannot be established by planting the associated species. A matrix of fast-growing tree and/or shrub species should be used to promote early woodland development. These would be removed during normal management which is essential for the ultimate success of the woodland. Planting schemes should also incorporate woodland structural elements and understorey and ground flora species.Provided that these measures are fully implemented, significant improvements in establishment, growth, and woodland development on restored sites should be achieved.
A trial was set up in 1990 in the Midlands coalfield in the United Kingdom (UK) to evaluate the use of sewage sludge to revegetate colliery waste tips containing 1 -2% sulfur as iron pyrites.The rate of sewage sludge application is currently restricted by legislation and codes of practice to maximum concentrations of potentially toxic elements (copper, nickel, zinc, etc.) in the soil or waste after application. Following this guidance, an application rate of 250 mt/ha dry solids was applied at the trial site. At this rate, the colliery waste became extremely acidic pH <4.0. From experience elsewhere, much higher levels have been found to be necessary to control acidification in the absence of other measures or treatments.In view of the restriction on the amount of sewage sludge that can be applied, it is recommended that the current practice of covering fresh colliery wastes with soil or low sulfur spoil to a minimum depth of 0.45m is continued in the UK. Where this is not possible, the sludge must always be applied with sufficient neutralising agent to control the potential acidity. If the acidity cannot be maintained above pH 5.0, the guidelines do not permit the application of sewage sludge.Additional Key Words: pyritic wastes, acidity, sewage sludge, soil cover. Pyritic Colliery Waste in the UK CoalfieldsCurrent coarse washery discard colliery wastes in the UK average between 0.2% and 2.0% sulfur in the form of iron pyrites (Glover 1984), although locally much higher levels are frequently recorded in the more pyritic wastes. The most pyritic wastes occur in the Midland coalfields of Nottinghamshire and Yorkshire and in the western Scottish coalfield. Modem waste tips are formed using earth-moving plant which, through compaction, has largely eliminated the risk of spontaneous combustion and reduced the oxidation of pyrite within the tip. There remains the potential for acid generation in the final surface layers, which generally are required to be uncompacted and permeable for the purpose of revegetation.While the modem construction methods for waste tips have much reduced the risk of acid mine drainage, there is still concern about surface acidification and subsequent pollution of watercourses and bodies by acidic runoff containing soluble salts and metals. Also, surface acidification can be of significance for restoration by causing poor vegetation growth and, in extreme cases, loss of vegetation. Both conditions can be time consuming and costly to rectify. Therefore, the prevention and treatment of acid potential and acidity has been, and continues to be, a priority in modern colliery waste restoration in the UK. https://doi.org/10.21000/JASMR94030324Practices for Treatment of Acidity Use of Neutralizing AgentsTraditionally, the method to control acid generation and to treat existing acidity in the surface layer of colliery waste has been to apply neutralizing agents, such as limestone (CaC03) or lime (CaO), as used in the management of agricultural soils (ADAS 198 I).Where the potential for aci...
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