Bioleaching is an emerging technology with significant potentials to add value to the mining industries so as to deliver attractive environmental and social benefits to all the associates. Chalcopyrite, CuFeS(2), is the most important copper-bearing mineral in the world and unlike many other ores it is known to be recalcitrant to hydrometallurgical processing. The main hindrance to the commercial application of biohydrometallurgical processing of chalcopyrite is its slow rate of dissolution. In this piece of review work, the microbiological and other important aspects of chalcopyrite heap bioleaching processes are discussed. The modest nutritional requirements of bioleaching organisms may be provided with the aeration of iron- and/or sulfur-containing mineral suspensions in water or the irrigation of a heap, while working in a large scale. This chemolithotrophic metabolism makes the organisms industrially important. The emphasis is given on the biodiversity of microbial community and the factors affecting heap bioleaching. The cost of bio heap leaching in respect of some existing commercially operating heap bioleaching plants is also included. Application of chalcopyrite bioleaching in heap/dump leach processes can potentially result in lower cost and reduced environmental impact in copper production. (C) 2007 Elsevier Ltd. All rights reserved.