The Bureau of Mines conducted bench- and small-scale continuous studies to develop a process for recovering a recyclable copper product from waste, granulated, blast furnace slag. The investigation was part of the Bureau's secondary resource recovery program. The slag contained 5 to 7 percent total copper, of which 3 to 4.5 percent was metallic copper. Tabling of the slag, ground through 35 mesh, recovered 58 percent of the total copper and 88 percent of the metallic copper in a concentrate that contained 39 percent copper. Flotation of the slag, ground through 65 mesh using a xanthogen formate collector, produced a concentrate containing 32 percent copper and recovered 76 percent of the total copper and 98 percent of the metallic copper. A small-scale continuous test was conducted to investigate simple gravity-separation techniques. A 40- hour test was made with a circuit that included rodmill grinding, a Humphreys spiral, and shaking tables. Two concentrates were prepared according to particle size; the plus 35-mesh concentrate contained 68 percent copper, and the minus 35-mesh concentrate contained 72.5 percent copper. The composite of the copper products contained 70 percent copper; the process recovered 60 percent of the total copper and 90 percent of the metallic copper. The research upon which this report was based was done under separate agreements between the Bureau of Mines, U.S. Department of the Interior, and two organizations, the University of Alabama and the Copper Div., Southwire Company, Carrollton, Georgia.