Agglomeration is a pretreatment step which binds fine particles to coarser particles. Typical objectives of agglomeration are to improve heap leaching recovery, reduce leaching time by enhancing solution distribution, and reducing fine particle migration which can result in plugging at the bottom of a heap. Initial binding mechanisms in the agglomeration process involve interfacial capillary forces which depend on three phase contact, such as a solid–liquid–gas interface. Appropriate liquid or moisture content plays a very important role in agglomerate formation. This study is for heap leaching ores but useful for other applications. It shows that optimal moisture needed for agglomeration can be estimated using liquid retention capacity measurements.