Trail of the motherlode

Metals, minerals, constructional raw materials, coal and chemical raw materials are essential to any modern industrial society. As known resources are worked out new ones need to be discovered to meet the future demands of society. Who "discovers " mineral deposits and what methods are used? Some 50 years ago most discoveries would have been made by prospectors whose art was centred on experience and the ability to recognise the signs of mineralisation at outcrop. Present-day explorationists have to search deeper and be able to detect far more subtle surface expressions of mineralisation. Consequently, the art of prospecting has developed rapidly into the scientific discipline of mineral exploration over the past 50 years. Initial discovery is only part of the problem. The size, shape, potential economic value and working costs of the discovery need to be established before mining can take place. Modern-day mineral exploration demands a multidisciplinary approach. The professional explorationist needs a variety of scientific and technical knowledge and skills to equip him/her for the task. Textbooks covering specific aspects of the subject, such as geochemical and geophysical methods of exploration, mineral deposit evaluation and mining geology, are already available. This present book, based on the MSc course in mineral exploration at Leicester University, is an admirable attempt at drawing together the full range of methods employed in mineral exploration, from prospect to mine, at a sufficient level for both practitioner and advanced student.

The book is a collection of 16 chapters written mainly by staff presently or previously involved with teaching on the MSc course at Leicester. It is divided into two parts. Part one, comprising 11 chapters, covers principles. The first three chapters on "Ore, mineral economics and mineral exploration", "The mineralogy of economic deposits", and "Mineral deposit geology" provide a reasonable introduction based largely on Anthony Evans's successful textbook on Ore Geology and Industrial Minerals. Chapters four and five on "Reconnaissance exploration" and "From prospect to predevelopment" are well written with lots of useful information and sound, practical advice. Chapter six on "Remote sensing and photogeology" is detailed and comprehensive but what a pity the illustrations were restricted to black and white images. Chapter seven covers "Geophysical prospecting" less successfully than I had hoped for. Technical aspects were kept to a minimum and the sense of cynicism about the worth of geophysical data in the wrong hands or from inefficient or inept geophysical contractors came over too strongly. Chapter 8 on "Exploration geochemistry" maintained a reasonable balance between practice and theory. I particularly liked the illustrations on the use of a goldpan, but I would have liked as clear a diagram showing the differences between secondary and primary geochemical dispersion patterns. Chapters nine and ten on, respectively, "Evaluation techniques" and on "Feasibility studies", were straight to the point and highly practical. The opening sentence to chapter ten: "Mineralisation is found, ore-bodies are defined and mines are made," is especially effective in highlighting the importance of these two chapters in the context of mineral exploration and development.

Part two is devoted to case-history examples illustrating the development of a mineral deposit from exploration to production (and in one case closure). Examples are selected on the basis of the authors' personal experiences, but the geological and geographical spread of different deposit types is reasonable. These range from UK examples of a hard-rock aggregate quarry in Leicestershire and a recently abandoned tin mine in Cornwall, through to lignite deposits in Turkey, a silver deposit in Nevada and the classic deposits of Kidd Creek, Ontario and the Wi****ersrand of South Africa. One might criticise the choice of examples. My list would certainly have included the recently discovered blind Cu-Sn ore bodies of Neves-Corvo, Portugal where modern exploration methods (notably geophysics) played such an important role. However, the accounts of the examples chosen are comprehensive enough and sufficiently illustrative of the principles outlined in previous chapters.

Overall, the book hangs together surprisingly well considering the number of authors involved and the wide-ranging nature of the subject. There is good cross-referencing and a useful further reading guide at the end of each chapter. There are numerous illustrations. Most are clear and informative, but a handful are of doubtful value or poor quality.

I have been waiting for a book like this for some time. I shall use it for my final-year undergraduate and MSc courses on mineral deposits to applied geology and earth science students. I recommend it to others teaching advanced level and postgraduate courses in mining geology, mineral exploration, mineral resource engineering and evaluation. The subject matter is, perhaps, too specialised for most general undergraduate geology degree courses but it provides a very good background to an important aspect of applied geology and it would make a very useful addition to any university geology library. Practitioners involved in mineral exploration or evaluation, even without a strong geological or mining background, will also find the book of interest and value.

Andrew Rankin is professor of applied geology and head of the school of geological sciences, Kingston University.