This paper gives a new correlation for viscosity of Bingham coal-water mixtures shear rate. Coal water mixtures of ash varying from 8 to 40% by weight show behaviour and Bingham plastic nature depending upon slurry concentration. It has been observed that the yield stress successively increases with ash content, A correlation predicts the viscosity at infinite shear rate eta(sic). The apparent viscosity of the slurry is obtained from the different measured parameters and the value of eta(sic).