Once the raw ore was liquefied, workers processed a slurry of uranium precipitate with an acid leach to rinse the dissolved uranium from the barren waste. In five 100-foot diameter wood stave thickener tanks, the dissolved uranium was further separated from the waste. Next came an ion exchange system to remove unwanted metals, followed by complete drying on huge rolls. A series of packaging maneuvers resulted in producing uranium concentrate, known as "yellow cake." In 1970 the Shirley Basin operation was redesigned as a new open-pit mine and mill with approximately the same capacity as at Lucky Mc. Circuit changes in 1975 increased the "throughput" of ore at the Shirley Basin mill from 1,200 tons per day to 1,800 tons per day.