Grade control and ore/waste delineation in open pit mining operations was traditionally based on the comparison of estimated grades with an economic cutoff. In the 1990s, an alternative approach to ore selection was applied and established, taking into account financial indicators through the so-called economic classification functions in combination with grade uncertainty assessment.

Rocks that form the outer part of the Earth, the crust, provide a record of constant change in the Earth’s environment with time in relation to the movement and/or reaction of rock material during their formation. Thus, understanding the genesis of rocks is the foundation of the geological knowledge system. The nature, size, shape, properties and arrangement of constituent minerals gives rise to the diversity of rocks and their origin so that the challenge of geology is in determining their material source and mechanism of formation. Among the three kinds of rocks, igneous, sedimentary and metamorphic, the material source of metamorphic rocks need not be considered because its predecessor is also rock. Igneous rocks derived by crystallisation of liquids can be divided into mafic and felsic end members represented by gabbro/basalt and granite/rhyolite, respectively, with different sources <...>

This volume brings together a collection of papers that summarize current ideas and recent progress in the study of granite-related mineralization systems. They provide a combination of field, experimental and theoretical studies. Papers are grouped according to the main granite-related ore systems: granite-pegmatite, skarn and greisen-veins, porphyry, orogenic gold, intrusion-related, epithermal and porphyry-related gold and base metal, iron oxide–copper–gold (IOCG), and special case studies. The studies provide a broad spread in terms of both space and time, highlighting granite-related ore deposits from Europe (Russia, Sweden, Croatia and Turkey), the Middle East (Iran), Asia (Japan and China) and South America (Brazil and Argentina) and spanning rocks from Palaeoproterozoic to Miocene in age.

The Grasberg Igneous Complex, which formed at ~3 Ma, is host to one of the largest copper and gold porphyry-type ore deposits discovered on Earth. This study focuses on the magmatic characteristics of the three main phases of intrusion at the level of the open pit mine: the Dalam, subdivided into the Dalam Andesite, Dalam Volcanic and Dalam Fragmental, the Main Grasberg Intrusion (MGI), and the Kali (Early and Late). A sample suite consisting of 225 polished slabs and thin sections shows all units contain plagioclase and biotite as the dominant phenocryst phases. The Dalam Andesite, MGI and Late Kali contain(ed) hornblende as well. The Late Kali and the MGI also contained minor amounts of clinopyroxene. Apatite is ubiquitous as a trace phase. Magmatic magnetite is identifiable in the Late Kali. The magmatic groundmass in the Kali, MGI, and Dalam Andesite was potassium feldspar, albitic plagioclase, quartz and biotite. A similar groundmass assemblage probably existed in the other Dalam phase rocks, but hydrothermal alteration caused complete replacement. The phenocryst assemblages record no profound changes in magma chemistry over time, but the parent chamber was probably recharged at least twice, and possibly many times.