The lifetime of artificial lift systems, such as progressing cavity pumps (PCPs), used to transport aqueous slurries which contain fine particles, e.g. coal fines, may be prolonged by incorporation of at least one dispersant in the slurries. The dispersants act to inhibit or prevent the fine particles from agglomerating to plug the artificial lift intake and/or inhibit or prevent the agglomerated coal fines settling above the artificial lift system. The dispersant may also improve the lubricity of the slurry.