Continuous three-phase slurry oxidation was successfully demonstrated in stirred reactors with blowback filtration and U-tube return of condensable solvent, as part of a fast-track development program. Four units were constructed for parallel life testing behind explosion-proof barriers. Periodic transient response testing was used to verify liquid inventories, and assess catalyst kinetics. Separate off-line units were implemented to examine recovery of trace catalyst, and testing of a solvent-free four-phase reactor concept. Details of problem solving needed for successful and safe implementation of an oxidation pilot program are presented.