La Sal ore from the Big Indian Wash district of Utah was treated for a second time in the Alkaline Leach - Filtration Pilot Plant at Grand Junction because of a suspected change in ore characteristics as mining progressed. The report contains detailed information on grinding, thickening, leaching, residue filtration, and precipitation. A section on mill design considerations is also included. Results show the ore to be amenable to the Alkaline Leach - Filtration process.

During the period of February 10 to May 8, 1958, Holly Blend ore from the Holly Minerals Company of the Ambrosia Lake district in New Mexico was treated in the Acid Leach - Contercurrent Decantation - Solvent Extraction Pilot Plant at Grand Junction, Colorado. This report contains detailed information on leaching, as applied in the processing of this ore. Results show the ore to be amenable to the Acid Leach - Countercurrent Decantation - Solvent Extraction process.