I THINK MINING

I am in South Africa and in the offices of a large consulting company.  They and the consulting community is abuzz with excitement and pride at the recent publication of a new book of tailings impoundment by Geoffrey Blight.  The book is Geotechnical Engineering for Mine Waste Storage Facilities.  It is readily available from Amazon for more than $300, but on the basis of a first read today, I must recommend it to all involved in tailings impoundments.

I have been honored to work with Geoff many years ago on two projects.  The first was the design of civil engineering works to control erosion from slimes dams around Johannesburg.  The second was the design of a tailings dam that never got built in north east Washington—the price of moly was too low to justify the mine.  But I know Geoff as one of the most intelligent men ever and a superb geotechnical engineer.  For many years he was professor and head of department at my alma mater, the University of the Witwatersrand in Johannesburg. 

In this book he collates his lecture notes on geotechnical engineering, many of the technical papers he has written over the years, the theses completed by students, and  his own intensely theoretical and practical insight and experience.  This is a book that brings up to date our long years of studying, working, and succeeding in the field.  This is a book for the ages and will, I predict, be the standard text for many decades to come.  It must be on the shelf of every geotechnical engineer working in tailings.

I particularly enjoyed reading his chapter on the grand tailings impoundment failures of South Africa: Bafokeng; Merriespruit; and others that I have not read about before now.  As he notes, many of them have not hitherto be written up and so the potential lessons learnt from them never entered standard geotechnical practice.  Now we have no excuse: Geoff sets them out in a way we cannot ignore—even to the extent of analyzing engineering & management failures leading to the slimes dam failures.  He is so honest that he even writes about the dishonesty and illegalities of mine managers that were the root cause of so many failures.  This is a refreshing honesty on his part that does not appear in any other book on engineering that I know.

    Geoff is a South African and the book reflects his work on South African tailings impoundments.  His is a particularly South African perspective and the book reflects this.  The fact is that tailings impoundment practice in the Americas is only vaguely similar to South African practice.  Thus there is little attention paid to the seismic response of tailings impoundments, or the problems of tailings disposal in cold climates, or the very soft tailings that are oil sands tailings.  While I still like the South African system for describing soils best, this is not the system used elsewhere.  His treatment of the use of CPTs to characterize tailings reflects the sparse use of CPTs in South Africa–which I am assured is increasing.    And his chapters on site selection and the Environmental Impact Statement preparation process reflects South African amazement (dare I say newness) of the system in South Africa rather than the North America fact that this is just another peripheral activity that is hardly touched by the civil engineer in practice.  I mean, do we need more pages on the preparation of EISs?  Not really, there are so many other far more specific books on the topic, that is make the book look distinctly naive and over-enthusiastic. 

Then there is the complete absence of any consideration of the fact that most analyses are now done using computer codes—do we really need another exposition on slope stability or sketching flownets? 

Another topic that Geoff neglects is the amazing fact that in South Africa, unlike most other countries of the developed world, there are no independent geotechnical peer review boards who look at all mine tailings impoundment on a regular basis and who report directly to mine management on their findings.  In South Africa it seems this standard practice is not practiced.  In my opinion, it should be.  For common sense and actual practice have long since shown that only independent peer review can preclude the thousand things that lead to the failure or poor performance of tailings dams.  No matter how professional your consultant, you need to have his work independently reviewed.  You cannot afford a failure or malfunction of your tailings dam, and, I submit, only peer review gets you 99 percent certainty that failures and/or malfunctions will not occur. 

But these are the minor quibbles of an idle traveller.  The book is superb, a must read, and pleasurable read, and an addition to the standard and great literature on geotechnical practice.  We owe Geoff a vote of thanks for laboring long and hard to put this together.