James E. Mungall edited and managed the short course delivered on behalf of the Mineralogical Association of Canada in Oulu, Finland, 6-7 in August 2005. The principal aim of the resulting book and the short course is to bridge a gap between exploration geologists and academics. In keeping with the educational mandate of UNESCO, which has generously sponsored the activities of IGCP Project 479, their goal was to disseminate current knowledge [as of 2005] of platinum group element ore genesis and exploration techniques to as wide an audience as possible worldwide.
To further promote global dissemination of knowledge, the book is now available for free download from the MAC on the Internet after a one-year moratorium. This book is designed to give a progression from the general to the specific, while focusing on factual information and avoiding unnecessary attention to some of the more contentious issues surrounding petrogenesis of PGE deposits.
Introductory chapters by J.E. Mungall and J.J. Hanley provide an overview of the geochemical controls on the distribution of PGE in the Earth's crust. An attentive reader should be able to apply the contents of these first two chapters to make critical appraisals of the enormous range of petrogenetic models they will encounter in the published literature on PGE deposits.
In the next section, R.G. Cawthorn gives an overview of the geology, structure, and geochemistry of stratiform PGE deposits hosted by layered intrusions. These deposits account for the lion's share of known PGE reserves globally.
The following article by M.J. Iljina and C.A. Lee describes PGE mineralization hosted by marginal facies of several major layered intrusions, which are increasingly dominating the tally of newlydiscovered deposits worldwide. The fate of precious metal mineralization in the weathering environment is discussed next by T. Oberthür and F. Melcher, who focus on the deeply weathered profile over the Main Sulfide Zone of the Great Dike of Zimbabwe.
The following article, by N.D. Tolstykh, E.G. Sidorov, and A.P. Krivenko, deals with the characteristics of placer deposits of PGE derived from deeply eroded Ural-Alaskantype mafic-ultramafic complexes. Historically these deposits were the primary source of PGE.
This section of the book concludes with an overview by A. Wilde of the geology of PGE deposits formed by hydrothermal or meteoric fluids, an extremely varied group of deposits that promises to grow to major importance in future despite their historical lack of economic importance.
In the following section of the book, attention swings from PGE-dominated deposits to those which are primarily deposits of the base metals, but which also provide economically significant PGE mine credits. The two largest such systems worldwide, the Sudbury mining camp and the Noril'sk-Talnakh deposits, are discussed first.
C.E.G Farrow, J.O. Everest, D.M. King and C. Jolette provide a revised classification and petrogenetic scheme for the PGE-rich facies of the Sudbury ore deposits. N.T. Arndt then discusses the structure and petrogenesis of the enormous magmatic sulfide deposits at Noril'sk in the conduit system that fed the Siberian Traps volcanic succession, as part of his description of the importance of magma conduits in the generation of PGE-rich deposits.
The vast and currently virtually unknown potential for PGE mineralization associated with Cu and Au-Cu porphyry deposits is discussed next by M. Economou-Eliopoulos, who provides a thorough summary of current knowledge of the distribution of PGE in these enormous deposits worldwide.
The third section of the book gives the reader a view of the principles and techniques presently used to direct and assist in the actual search for new deposits of the PGE. All of the articles in this section were written by people with extensive applied experience in the methods they describe. A. Green and D. Peck share their views on the fundamental economic and geological considerations that must inform the explorationist in his or her search for a prospective region in which to explore. An overview of the geophysical tools available to help in the detection of PGE deposits is given by S. Balch. E.M. Cameron and K. Hattori describe a variety of methods of detection of PGE deposits based on sampling of surficial materials, after which W.D. Maier and S.-J. Barnes show how to use systematic studies of whole rock geochemistry to infer the presence of invisible or buried PGE mineralization in large magmatic systems.
The fourth, and final, section of the book is a series of case studies outlining how several major deposits of the PGE were discovered or brought into a state of feasibility for exploitation:
F.P. Mitrofanov and others describe the discovery of mineralization in the Fedorov-Pana intrusion in the Kola Peninsula, giving valuable insights into the approaches necessary for exploration in areas of low topographic relief and deep permafrost.
S.A. McLean, K.H. Straub, and K.M. Stevens then show how a well-conceived exploration program in the shadow of a head-frame turned up an important new discovery at the Nickel Rim deposit, in a mining camp that has already seen over a century of determined exploration.
The discovery and development of the Lac Des Iles palladium deposit is described by M.J. Lavigne, M.J. Michaud and J. Rickard, who give a frank assessment of the relative utility of the various exploration methods available in areas of thin but persistent recent glacial overburden in the boreal forest.
The importance of soil geochemical surveys in the discovery of the J-M reef of the mountainous Stillwater intrusion is then discussed by M.L. Zientek, S.R. Corson, and R.D. West.
One of the eternal problems facing miners of PGE is grade control, due to the commonly invisible nature of the ore minerals. This important topic is addressed in detail by A.H. Wilson and R.T. Brown, in their account of the development of the Hartley Platinum Mine in the Main Sulfide Zone of the Great Dike of Zimbabwe. A fascinating account of serendipity and perseverance in the discovery of the extremely well-hidden Platinova Reef of the Skaergaard intrusion is given by T.F.D Nielsen, J.C.O Andersen, and C.K. Brooks. Theirs is a lesson well taken, in the ease with which major deposits of the PGE can be overlooked even in the most-intensively studied rocks in the world.
The concluding case study is that of the Sukhoi Log orogenic Au-Pt deposit in central Asia, written by V.V. Distler and M. Yudovskaya. Their study shows how the application of unconventional ore deposit models to apparently conventional deposits can pay off in the discovery of PGE mineralization.
The book concludes with a PGE ore deposit classification and accompanying thematic maps of PGE deposit distribution worldwide, prepared by R. Eckstrand and L. Chorlton from data contained in the database of the World Minerals Project of the Geological Survey of Canada. With contributors originating or working in countries including Canada, the USA, the United Kingdom, Germany, Greece, Finland, Denmark, Russia, Japan, South Africa, Zimbabwe, and Australia, this book is the fruit of a truly international effort by dozens of people representing the best of academic and industrial experts on PGE deposits. As Editor, I am indebted to them and to a small army of reviewers who gave generously of their time to keep the book balanced, accurate, and topical.
This book is published by the Mineralogical Association of Canada as the handbook to accompany Short Course "Exploration for Platinum Group Element Deposits". The course is also sponsored by International Geological Correlation Project 479 "Sustainable Use of PGE in the 21st Century: Risks and Opportunities", the United States Geological Survey, and The Society of Economic Geologists. Financial support permitting presentations of chapters at the short course by employees of Falconbridge Ltd, FNX Mining Company Inc, Aeroquest Limited, and Ridge Mining has been instrumental in the success of the short course.
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