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Current and future supply of minerals
Published in Natalia Yakovleva, Edmund Nickless, Routledge Handbook of the Extractive Industries and Sustainable Development, 2022
Karin E. Olson Hoal, Eric Pirard, Alan R. Butcher
Minerals and metals come from areas of the Earth in which they have accumulated and concentrated, and from which they may be recovered economically. Geological processes acting over millions or billions of years produce ore deposits, and understanding these deposits, how they formed, and how best they can be extracted, is the role of economic geology. Considerations include high-pressure and high-temperature natural forces acting within the Earth, with hot, acidic fluids (such as sulphidic hydrothermal fluids) percolating between mineral grains, dissolving and re-precipitating elements with subtle changes in physical and geochemical conditions, all of which act over time to concentrate and precipitate ores in useful concentrations. Excellent references that detail the occurrence and extraction of mineral resources include the extensive review by Arndt et al. (2017), processing manuals such as Wills and Finch (2015), to the geology and mining series in the Society of Economic Geologists Newsletter Discovery (Wood, 2018; Carlson, 2019; Chitombo, 2019; Holloway and Cowie, 2019; Wood and Hedenquist, 2019).
Our Environment
Published in Karlheinz Spitz, John Trudinger, Mining and the Environment, 2019
Karlheinz Spitz, John Trudinger
Economic geology is the branch of geology that deals with the genesis and nature of ores, and the range of techniques used to discover and evaluate these ores. Rocks are classified into three categories, based on their origin: Igneous rocks are those which solidify by cooling of magma, either within the Earth’s crust (plutonic rocks) or extruded on to the Earth’s surface (volcanic rocks). These rocks are categorized and classified by their chemical and mineralogical composition and texture. Common examples include granite which is a plutonic rock of acidic composition, and basalt which is a volcanic rock of basic (alkaline) composition.Metamorphic rocks result from the transformation of preexisting rocks under conditions of high temperature and/or high pressure, which change the mineral assemblages and also cause textural changes, particularly the development of mineral banding and foliation. Classification of metamorphic rocks is based partly on the characteristics of the pre-existing rock, as well as the type and grade of metamorphism as reflected in the mineral assemblage and the texture. Examples are slate (which results from low grade metamorphism of shale), schist which results from higher grade metamorphism, and marble, which results from recrystallization of limestone at high temperature.Sedimentary rocks which form by deposition and accumulation of particles from weathering of other rocks; particles ejected into the atmosphere by volcanic eruptions; the solid remains of organisms; and crystals and colloids precipitating from surface waters. Deep burial, consolidation over time and in some cases intergranular reactions cause the deposited sediments to lithify, i.e. become rock. Classification of sedimentary rocks is based mainly on composition, and grain size. The most common sedimentary rocks are sandstone, shale, and limestone. Peat and coal are also classified as sedimentary.
Formation of Cu–Au porphyry deposits: hydraulic quartz veins, magmatic processes and constraints from chlorine
Published in Australian Journal of Earth Sciences, 2023
G. N. Phillips, J. R. Vearncombe, J. D. Clemens, A. Day, A. F. M. Kisters, B. P. Von der Heyden
We address these questions in what represents a significant departure from the traditional magmatic model for these deposits, and we suggest that partitioning of the metals involving a silicate magma is not necessary. We can begin to answer some of these questions by introducing information from outside economic geology, especially from structural geology and hard rock (igneous and metamorphic) petrology. This study has selectively focused on the roles of rheology, rock mechanics, vein control, metal-enrichment processes and the sources of Cl. It has also proved beneficial to draw information and ideas learned from the study of other gold deposit types (e.g. gold-only deposits), which, although having some stark contrasts, inform on the general behaviour of the element gold in Earth’s crust. There is no attempt to discuss the many other anomalous elements such as Mo at this stage, as any viable model needs to adequately explain the origins of Cu and Au regardless of any other elements.
Abstracts from the early-career researchers virtual International Platinum Symposium, May 2022
Published in Applied Earth Science, 2022
The presented research encompassed traditional meeting themes of igneous petrology and economic geology pertaining to mafic-ultramafic rocks, as well as novel themes of non-conventional platinum-group element repositories and the applications of machine learning in mineral exploration. Several studies focussed on the world-class Bushveld Complex of South Africa, particularly the complex's northern limb which has become one of the world's most exciting exploration frontiers for platinum-group elements, nickel, copper, chromium, and vanadium. The mobility of magmatic sulphide liquids in trans-crustal systems also features in several studies, and more specifically, the roles in which volatile phases may play to facilitate the migration of immiscible sulphide liquid. Lastly, some abstracts focus on petrogenetic aspects of established mafic-ultramafic complexes, such as the Noril'sk-Talnakh, Coldwell, and Stillwater complexes.
Economic geology, principles and practice: metals, minerals, coal and hydrocarbons – an introduction to formation and sustainable exploitation of mineral deposits, 2nd ed.
Published in Applied Earth Science, 2020
This is a book I would have appreciated throughout my career in the mineral industry and in university teaching. It is broad in what it covers but also detailed in the amount of information it has brought together. A listing of the seven chapters illustrates how broad Economic Geology is: metallogenesis and ore formation, three chapters on economic geology covering metals, industrial minerals, and salt formations, then the mining cycle, coal, and petroleum with hydrocarbons. Each chapter is comprehensive whether it involves a complete coverage of all major ore formation processes or a systematic description of over thirty elements one-by-one linking their chemistry, behaviour in geological systems, modes of formation and commercial significance.