Heap leaching and dump leaching

The document does not contain an explicit abstract or summary section. Here is a synthesized abstract based on the text: The paper describes and compares heap leaching of crushed ore and run-of-mine (ROM) dump leaching at Gold Fields’ Mesquite Mine in Imperial County, California, where expanded low‑grade ore processing has enabled a significant increase in production capacity. It outlines the mine layout and ore grades, and details the crushing and agglomeration circuits, pad construction and lining, and solution application via drip irrigation. Operating parameters such as leach cycle times, gold recovery (typically about 80% overall, with roughly 15% higher recovery for crushed ore than ROM), and reagent consumption are presented, along with reasons for Mesquite’s unusually low cyanide use. The design and performance of the carbon adsorption plant and refinery are summarized. An economic comparison shows that the additional costs of crushing, agglomeration, and handling are offset by relatively small incremental recoveries (0.03–0.06 g/t), making heap leaching generally preferable for most low‑grade ores, while dump leaching remains a useful supplemental outlet when crushing capacity is constrained.