The U.S. Bureau of Mines is investigating a systems approach to metals recovery from acidic liquors produced by in situ leach mining of chrysocolla- and atacamite-bearing ores. A 5-cm-diam, 14.6-M column packed with ore was utilized to simulate the long leaching paths between injection and recovery wells in an in situ operation. Atacamite-bearing copper ore was utilized in the 14.6-M column to determine variations in solution composition and precipitate formation as the leach liquor moved through the column. Columns 15.2 Cm in diameter by 1.8 M long, packed with chrysocolla-bearing ore, were integrated with continuous solvent extraction- electrowinning circuits to assess impurity ion buildup during recycling of leaching solution. Leach liquor impurity ion concentrations and acidity were examined with respect to their effect on leaching and metal recovery operations. Results indicate that leach solution acidity should be varied as a well field ages, and leach liquors from various recovery wells should be blended, to achieve consistent leach liquors and facilitate efficient metal recovery procedures. Also, additional metal recovery procedures may be necessary to prevent impurity ions from reaching saturation levels and decreasing ore body permeability through precipitation. Research should be conducted on processing highly acidic (ph I 1) copper leach solutions, which may be necessary to prevent impurity precipitation.