In the thermal power plants, fly ash is normally transported through slurry pipelines to the ash ponds. The objective is to study the possibility of transporting coal fly ash suspension at higher solid concentrations with and without coal bottom ash addition. The physical, chemical and rheological characteristics of the coal fly and coal bottom ash have been determined at different solid concentrations. The solid concentration of coal fly and coal bottom ash suspension was ranges between 10 and 60% (by weight). The coal bottom ash is mixed with coal fly ash with 10, 20 and 30% of solid concentration (by weight). It is perceived that the coal fly ash fine particles are spherical in shape whereas coal bottom ash particles are irregular and coarser in nature which leads to more drag effect in slurry pipelines. The addition of coarser coal bottom ash particles in finer coal fly ash improves the rheological characteristics of coal fly ash slurry suspension. The optimum reduction in relative viscosity of fly ash was found with 20% proportion of bottom ash mixture. The investigation reveals that fly ash suspension in above manner has a potential to transport in slurry pipeline with minimum energy consumptions. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.