At its College Park Metallurgy Research Center in Maryland, the Bureau of Mines has installed and is operating a 5-ton-per-hour pilot plant for continuous mechanical separation of values contained in raw urban refuse. The entire system was assembled using commercially available equipment. The process relies on multistage processing including shredding, air classification, screening, gravity concentration, and electrostatic separation. Compactor trucks deliver raw refuse collected along typical routes in metropolitan Washington, DC, to the pilot plant. The loads are separated into concentrates of light-gage iron, massive metals, glass, putrescibles and waste combustibles, paper, and plastics. While some refinements remain to be made in the processing system flowsheet, the data obtained to date have been highly encouraging, indicating favorable economics for commerical-size plants.