Impact of geochemical processes on ash dumps at coal-fired power plants

The accidents and hazardous conditions at ash dumps of coal-fired power plants as a result of interaction of engineering, hydrogeological and geochemical factors are discussed. The most typical causes of the incidents are instability of dams, overfill of ash dumps, destruction of drainage and pipeline systems, seepage processes, local leaks and impact of extremal hydrometeorological conditions. The consequences of such events are contamination of surface water and groundwater, fly ash transport, secondary pollution of soil and functional failure of ecosystems in the neighborhood. Emphasis is laid on the role of geochemical processes in accident risk development at ash dumps. It is found that after ash and slag piling, hydration, leaching, migration of elements, secondary mineralization, redox alteration of iron and initial soil formation take place in the body of an ash dump. These processes change composition of pore water, permeability, level of saturation with water, chemical aggressiveness of the medium and spatial non-uniformity of ash mass. As a result, local overwetting, mudding or redistribution of seepage flows, degrading of drainage elements, corrosive attack on concrete and steel structures grows, and the stability of dams drops. It is concluded that the accident risk at ash dumps is governed not only by the technical condition of the structures but also by the long-term geochemical evolution of the ash mass. The essentiality of the continuous geochemical, hydrological and engineering monitoring is substantiated for the safe operation, deactivation and reclamation of ash dumps. 

Valtseva A. I., Valtsev N. V., Morozov Yu. P., Barbin N. M., Shvets M. A. Impact of geochemical processes on ash dumps at coal-fired power plants. MIAB. Mining Inf. Anal. Bull. 2026;(11-1):98-112. [In Russ]. DOI: 10.25018/0236_1493_2026_111_0_98.

A.I. Valtseva¹, Cand. Sci. (Eng.), Assistant Professor, e-mail: a.i.valtseva@urfu.ru, ORCID ID: 0000-0003-0094-0775,
N.V. Valtsev¹, Senior Lecturer, e-mail: n.v.valtsev@urfu.ru, ORCID ID: 0009-0008-3001-5103,
Yu.P. Morozov, Dr. Sci. (Eng.), Professor, Ural State Mining University, 620144, Yekaterinburg, Russia, e-mail: tails2002@inbox.ru, ORCID ID: 0000-0003-0554-5176,
N.M. Barbin¹, Dr. Sci. (Eng.), Professor; Ural Institute of the State Fire Service of the Ministry of the Russian Federation for Civil Defense, Emergencies and Elimination of Consequences of Natural Disasters, 620062, Yekaterinburg, Russia, e-mail: n.m.barbin@urfu.ru, ORCID ID: 0000-0002-6709-4334,
M.A. Shvets¹, Leading Programmer, e-mail: m.a.shvets@urfu.ru, ORCID ID: 0009-0000-8972-2947,
¹ Ural Federal University named after the First President of Russia B.N. Yeltsin, 620062, Yekaterinburg, Russia.

A.I. Valtseva, e-mail: a.i.valtseva@urfu.ru.

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