Pipeline transport in the form of a slurry can reduce the cost of transportation of biomass material to a bioreflnery, as compared to trucks. This research experimentally studies the hydraulics of slurries of wheat straw with water for pipeline transport. Slurries with a range of particle sizes and saturated solid mass fractions are examined in a laboratoryscale 50 mm diameter carbon steel pipeline system. Slurries with particles approximately 3 mm long can flow with saturated solid mass fractions of up to 30%. Pressure loss gradients results suggest the influence of drag reducing fibre suspensions. This phenomenon enables slurry pressure losses to be below that of the carrier fluid alone (water) and be achieved with sufficiently long particle sizes, low saturated solid mass fractions and high velocities. Our results suggest that to reduce pressure losses per unit biomass material, slurries should have short particle sizes, to allow high saturated solid mass fractions to be pumped at low velocities. With the pipeline system and slurries examined in this study, slurries with particles approximately 3 mm long and saturated solid mass fractions of 20 30% pumped at 1.5 m s(-1) experience the lowest pressure losses. This result helps in the design and optimal operation of biomass slurry pipeline systems. (C) 2014 Elsevier Ltd. All rights reserved.