Evaluation of Some Parameters in Relation to Hydraulic Stowing of Pond Ash in Underground Coal Mines: A Prototype Study

Abstract

Various parameters in relation to hydraulic stowing of pond ash such as rate of water drainage from the pond ash, water absorption by the pond ash, percentage of stowing and percentage of void were evaluated using a mine goaf model stowed with pond ash slurries of five concentrations varying from 45 to 65 % at 5 % increment to identify the suitable slurry concentration for effective stowing in underground coal mines. The study revealed that the rate of water drainage from the stowed pond ash is highest during the initial 15 min of stowing and it gradually decreases with time. Also, it was observed that the percentages of water absorption by the pond ash and stowing increase with the increment of slurry concentration. It was concluded that pond ash slurries of higher concentrations such as 60 and 65 %, which yield better results in terms of higher stowing percentage in the 1st phase of stowing itself and higher water absorption, may be considered appropriate for stowing.