A pumpable aqueous slurry of a solid fuel in the form of a pulverized, carbonaceous material and a process for the production of such slurry are described. The aqueous slurry comprises a component which consists of coarse grains of carbonaceous material having a particle size of up to 25 mm, and a further component which consists of a carrier liquid in which the coarse-grained carbonaceous material is suspended. The carrier liquid proper has a solids content of 65-90% by weight and consists of water and pulverized, carbonaceous material having a particle size of at most 0.5 mm, preferably at most 350 .mu.m, and 0.02-2% by weight of at least one additive including a water-soluble surface active compound which consists of an alkylene oxide adduct having a hydrophobic part and a hydrophilic part, said hydrophilic part consisting of a polyalkylene oxide chain, preferably a polyethylene oxide chain, having a length of 40-200 alkylene oxide units. The pumpable aqueous slurry is produced by first preparing the carrier liquid and then adding to said liquid 20-40% of the coarse-grained, carbonaceous material, based upon the total weight of the aqueous slurry. The aqueous slurry is intended primarily for pumping in pipelines.