| Popis: |
For centuries, coal has been a reliable source of energy; however, despite terms such as “clean coal,” coal is considered “dirty.” Unlike other fossil fuels, coal is a solid and in its rawest form contains significant quantities of incombustible impurities, which must be dealt with before, during, and after mining. Overburden waste, processing refuse, and coal combustion residuals constitute large volumes of material that must be handled and managed. Handling segregates waste material into coarse and fine fractions. Coarse fractions are used to construct impoundments into which fine fractions are pumped. Storage piles quickly become part of the “natural” landscape, but unless properly constructed and maintained, they can have long-term negative impacts on the surrounding environment including generation of geochemical pollutants and creation of geotechnical safety hazards. After defining coal waste and sustainability, traditional coal waste disposal practices are briefly summarized. The remainder of the chapter focuses on sustainable coal waste disposal practices of the future. The first is eliminating slurry impoundments by codisposal of coarse processing waste and dewatered fine processing waste. This practice requires low-cost, efficient dewatering technology for fine waste material, and two contemporary options are discussed. Next, backfilling is explored as an alternative to stowing coal waste in expansive surface landfills. Finally, the sustainability principles of reduce, reuse, and recycle are examined from the coal mining perspective, an approach that can seem counterintuitive unless a holistic viewpoint is taken. |
