GUIDELINES TO ENSURE AN ENVIRONMENTALLY SUCCESSFUL DEVELOPMENT OF THE COAL SECTOR
Land reclamation after mining is the main environmental concern. It is technically feasible, at a cost, in most areas. Reclamation can be carried out most successfully and cost-effectively when provision therefor has been made an integral part of the mine development plan. For the successful development of mining activities:
• The process of enforcement of environmental legislation, e.g. reclamation, should be conducted in a manner which avoids or minimises delays and associated costs;
• The calculation of the cost of coal should allow for the cost of future land reclamation made necessary by its production;
• An assessment of environmental and socio-economic impact should be undertaken when establishing mining activities in areas where there has been no coal mining;
• Drainage of water containing acids and heavy metals from mining and/or waste disposal, which is a threat to ground and surface waters, should be abated and techniques should be used which minimise the total cost, including the social cost;
• The highest practicable degree of occupational health and safety for miners should be assured.
B. Transport and Handling
Transport of coal has environmental advantages over transport of oil and liquid natural gas when considering the possible impact of shipping accidents. For improvements in the transport and handling of coal:
• Measures should be implemented to control environmental disturbances when coal is loaded and unloaded, from coal stockpiles and from railroad cars, trucks and barges and in using new coal transportation systems;
• Consideration should be given to the continuing demands made on water resources and the need to ensure that the discharged water is of acceptable quality when coal slurry transport or coal washing techniques are employed;
• Efforts should be intensified in coal cleaning and blending techniques to provide coal of uniform quality, which is specifically important for small-scale plants.
C. Utilisation -- Air Pollution
Most countries have already taken measures to achieve an acceptable ambient air quality, including, among others, restriction of coal use to certain less polluting systems or combustion modes. In areas where coal use is to be increased:
• Possible environmental impact should be assessed and the most appropriate cost-effective remedies available -- both short and long-term -- employed to minimise the damage;
• Taking into account their cost-effectiveness, the best available abatement techniques should be employed to minimise the emission of particulates and SOx in order to ensure that no significant degradation of the environment will occur, both within and beyond national frontiers;
• Proven technologies for reducing NOx emissions should be used, taking into account their costs and advantages. These technologies would include new combustion system designs, including improved burner, fluidised beds and flue gas denitrification;
• Gaseous and particulate carcinogenic pollutants and by-products should be strictly controlled;
• emissions and ambient air quality should be adequately monitored to ensure that requisite guidelines are followed and standards are met;
• priority should be given to the burning of less polluting coal while applying and developing further the appropriate technical and economic means for controlling emissions from more polluting coals, with due regard to relevant constraints.
D. Utilisation -- Solid Waste
An expansion of coal use will increase the quantities of waste requiring disposal or utilisation. For areas where coal use is to be increased:
• An assessment should be made of all environmental implications and associated environmental costs of those air pollution control technologies which produce solid waste to ensure that water and land impacts are controlled;
• Practical guidelines for controlled ash disposal should be developed;
• The environmental consequence and costs of coal preparation and the disposal of resultant wastes prior to burning should be examined;
• An examination should be made of the desirability of incentives needed to extend the existing commercial uses for fly ash and desulphurisation waste; and increased effort should be directed towards demonstrating the practicality of solid waste utilisation, taking into account its impact on the environment;
• An examination should be made of the desirability of incentives needed to encourage disposal of the wastes into the mine and their environmental consequences.
E. Utilisation -- Labelling of Coals
Coals entering world trade may not be sufficiently characterised with respect to the properties which have a potential environmental impact which makes it difficult for users to judge whether the composition is adequate to meet national environmental standards. To improve this situation:
• The sulphur characteristics (e.g. data needed by physical preparation plants) of all coals entering world trade should be specified in a standardized manner;
• An examination should be made of how coals entering world trade should be assayed as to their metal content.
F. Utilisation -- Research and Development Requirements
There are many environmental aspects of the coal cycle which require further research. Co-ordination of this research internationally could be advantageous. In particular:
• Increased efforts should be made to develop and commercialise cost-effective advanced control technologies for coal combustion, including new systems such as fluidised bed combustion, in order to use coal more efficiently and diminish adverse impact on the environment;
• More R&D should be pursued to develop coal conditioning agents which would promote sulphur capture by the ash;
• An assessment should be made of the fate of metals released from the coal during combustion followed by particulate control using electrostatic precipitators and baghouses;
• Alternative combustion systems should be evaluated for their ability to control NOx emissions;
• New processes for the use of coal (e.g. coal gasification, coal liquefaction) which are environmentally beneficial, should be further developed;
• Beneficial use of by-products, including waste heat and the chemical constituents of liquid wastes, should be encouraged.