Abstract: A process for producing a flowable concentrated aqueous slurry of insoluble coal products from a dilute slurry of insoluble coal products. The dilute slurry is concentrated to form a nonflowable concentrate having a solids level in excess of 65 weight percent. The nonflowable concentrate is introduced into a mixing zone together with an alkaline agent, surfactant and diluent wherein they are admixed to form a flowable concentrated aqueous slurry having a solids level in excess of 60 weight percent. Sufficient alkaline agent is present to provide a pH level of the slurry above about 9.0. The surfactant comprises at least about 0.01 percent by weight of the solids present. The diluent can comprise any suitable aqueous stream that does not adversely react with the insoluble coal products, alkaline agent or surfactant. The concentrated aqueous slurry is easily flowable from the mixing zone.