Science in Practice Portal

The proposed cyanide heap leach facility consisted of a 230-by-150-foot pad, pregnant and barren solution ponds, and a Merrill-Crowe zinc precipitation plant. The metal precipitate was smelted on site. A solution containing about 5 pounds of sodium cyanide per ton of water, buffered to pH 11 with lime, was applied by a sprinkler system to the top of the ore stacked on the leach pad. Ore hauled from the Jumbo Mine in the Tintic Mining District was placed on a heap leach pad lined with a single layer of 40-mil PVC over compacted native soil. Coarse-grained ore was placed on the pad first, with finer-grained material on the top, to a total thickness of 6 feet