The interactions of dissolved or colloidal actinides with tuffaceous rock are being studied at Los Alamos National Laboratory in support of the Nevada Nuclear Waste Storage Investigations project. We have used small columns of crushed tuff to obtain information on the sorption of neptunium, plutonium and americium during short (<1 day) time spans. Data from these experiments supplement information obtained from longer term batch-type experiments and provide insight concerning sorption kinetics, speciation, and colloid migration. We find that Np(V), Pu(VI) and Pu(V) show limited sorption on crushed tuff. Pu(IV) polymer and Am(III) are largely retained by the tuff, with a small fraction of the imput material moving through the column as colloids.