Based on the extensive experience of heap leaching operations, crushed ore agglomeration can be successfully considered and utilized as a pretreatment step for the heap leaching of ores containing significant amounts of fines and clay minerals. The drum agglomeration is considered as a pretreatment step for the heap leaching of copper and gold ores whereas the agglomeration of uranium and nickel ores has received less attention over the past years. The acceptance of binder application for acidic leaching systems is limited primarily due to the lack of acid-tolerant binders. The use of binder depends mainly upon the cost considerations, impact on recovery and safe practice. Of equal importance are the quality control and characterization tools for the agglomerates to ensure better heap performance. This paper attempts to provide a concise overview of available quality control and characterization tools for crushed ore agglomeration with industrial examples from the gold, copper, nickel and uranium operations. Consequently, different agglomeration-heap leaching systems and their differences are summarized. The requirements for effective agglomeration, characteristics for an ideal agglomerate and integrated flow-sheet of crushed ore agglomeration-heap leaching system are discussed. (C) 2012 Elsevier Ltd. All rights reserved.