Disclosed embodiments include a feedstock preparation system that includes a first slurry preparation system that may receive a first portion of a solid fuel to generate a first fuel slurry using the first portion of the solid fuel and a liquid and second slurry preparation system separate from the first slurry preparation system that may receive a second portion of the solid fuel and the first fuel slurry. The second slurry preparation system may produce a second fuel slurry using the second portion of the solid fuel and the first fuel slurry. The first fuel slurry has a first particle size distribution and the second fuel slurry has a second particle size distribution, and the first and second particle size distributions are different.