Mining often results in the contamination of groundwater by metal, sulphate and radionuclide ions following their percolation from tailings impoundments. This chapter discusses the processes by which elements within tailings are transformed and translocated to groundwater and the role of aquifer characteristics and colloids in these processes. The prevention and remediation of contaminated groundwater is also discussed, with particular attention given to the use of permeable reactive barriers and sulphate reducing bacteria.
Part of the book: Groundwater
Nano-sized particles (1–100 nm) comprise a considerable fraction of coal fly ash (CFA). They are unique due to their large surface area and higher reactivity compared to larger CFA particles. As they are formed by nucleation of volatilised elements or through chemical reactions, nano-scale CFA particles have been shown to take up greater quantities of elemental ions and bind them more strongly than larger particles, diminishing the fraction of desorbed ions. Despite this and the large volume of literature on acid mine drainage (AMD) treatment using CFA, little is described about the specific role of nanoparticles in this process. This chapter therefore sets out to highlight this, beginning by delineating nanoparticle characteristics that make them good adsorbents followed by details of their formation and action in metal adsorption.
Part of the book: Coal Fly Ash Beneficiation