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GEOSTATISTICAL ASSOCIATION OF AUSTRALASIA
No. 3, September 1997.


 

GAA goes "regional and environmental"
The first Regional Meeting in Kalgoorlie
Affilitations and contacts with professional organisations
What is geostatistics? Who is a geostatistician?
The use of semivariograms in practice
Revision of the JORC Code
Second Perth Meeting: Environmental Applications
GAA 1997-1998 Executive Committee
Calendar of Events
Membership
Corporate Members and Sponsors
Postgraduate Certificate in Geostatistics
Book Review
Call for Papers
Geostatistical Simulations for the Mining Industry

GAA goes "regional and environmental"

Two important meetings have just taken place: the first regional get-together was held in Kalgoorlie on Friday 22 August and attracted a large audience, and GAA’s second meeting in Perth was a well-attended first environmental talk by Dr Geoff Riley on Friday 5 September. Both meetings led to lively discussions that show how we benefit from such informal get-togethers. On Tuesday July 1, 1997, Louis Voortman presented a short talk on "Why we need statisticians" to the Statistical Association of Australia, Perth Branch (at the invitation of Statistical Association) and presented his ideas on areas of statistical research which would directly benefit both statisticians and geostatisticians.

During the past two months, the Exec Committee unfortunately faced the absence of some of its members on demanding overseas assignments and we had to postpone a meeting planned for the end of September. The good news is that Danie Krige will be visiting Australia from South Africa in November and Margaret Armstrong will be arriving from Fontainebleau in December. We will do our utmost to ‘grab’ Danie so that GAA members can meet him, either professionally or socially, while Margaret has offered to give us a presentation on Friday 12 December!

In this Newsletter you will find a thought-provoking contribution by John Henstridge on "who should we consider as a geostatistician", remarks by John Vann on the latest developments in the JORC code, a call for papers on sampling control by Brian Davis, a notice of a new postgraduate geostatistics certificate by Lynn Bloom at Edith Cowan University and of a course by Roussos Demitrakopoulos at the University of Queensland.

After our first six months in existence, our records are healthy: we have around 65 paid-up members, a positive bank balance and have already gone out into the regions. Much of this is also due to the support of our early corporate members and sponsors: Snowden Associates, Geoval, WMC, Data Analysis Asutralia and Great Central Mines in Perth and Sydney, KCGM and EMC in Kalgoorlie. Their support right from the start has been much appreciated!! We are actively seeking further support from corporate members and we will keep you updated on progress in the next Newsletter. Please also note the section on our planned meetings for the remainder of this calender year at the end of this Newsletter and our very first book review (no mean feat, just try it!) by Tatiana Skvortsova of Geoval on environmental and geotechnical uses of geostatistics. Who has the courage to follow Tatiana’s example for our next Newsletter?

Louis Voortman, Newsletter editor, email lvoortman@snowdenau.com


The first Regional Meeting in Kalgoorlie

GAA’s first regional meeting was held on the 22nd August 1997 at the Railway Motel in Kalgoorlie. It was an immediate and fantastic success with the attendance of 35 people, some travelling 300 km just to be there on a Friday night! Many apologies were received with a suggestion that a Thursday night would be easier to attend.

The evening kicked off with an inspirational opening address by Louis Voortman, GAA's Vice President, followed by an excellent presentation by Michelle Franks of Snowden Associates on "How the Mill Can Drive Grade Control". An anonymous attendant suggested that a more appropriate title might be "How the Mill Can Drive You Bonkers"! A lively discussion followed with the offer of many presentations for our next get together, even if they were under the influence of alcohol at the time! The attendants were asked what the agenda should be for the next meeting, as GAA wants to ensure that practical and relevant subjects are selected for informal and instructive discussions. Interests ranged from "What is Geostatistics?" to queries on more advance grade estimation techniques such as the use of Conditional Simulation techniques in grade control. It is apparent that the focus in this region is on the practical application of geostatistics such as What?, When?, How ? and Why?

The venue and catering were excellent with many thanks to our sponsors for the evening: KCGM, EMC and Snowden Associates. It was great too to catch up with old and new acquaintances, to hear what they were up to, both socially and technically. I look forward to our next get together, planned for the end of November or early in December.

Donna Kelly, GAA Regional Representative Kalgoorlie, email dkelly@kalgold.com.au


Affilitations and contacts with professional organisations

GAA has been approached by Dudley Kingsnorth, AusIMM Councillor for Perth, and we have invited him to attend one of our Executive Meetings. This will enable us to establish formal contact with the AusIMM and discuss points of mutual interest. Due to circumstances, this contact has not yet taken place but it will happen in the near future. Should you have any suggestions for topics which should be included, please mail your suggestions to John Vann on email geoval@ozemail.com or Ian Glacken on email ian.glacken@wmc.com.au.

GAA was also contacted by Tom Bowling of the Australian Geomechanics Association in Hobart, Tasmania, for more information on our Association. We sent him copies of our latest Newsletters and, hopefully, we can establish closer contact in future. In fact this leads to a very important question: what precisely should "we" consider to be geostatistics???


What is geostatistics? Who is a geostatistician?

The process of establishing the Geostatistical Association of Australasia highlights the above questions. Is geostatistics a collection of techniques or is it an area of application? Is a geostatistician someone purely concerned with ore reserve estimation or is it someone with more general interests. These questions raise issues concerning our identify. Who are we targeting our Association at? What areas are we trying to promote?

In trying to answer this question I am reminded of a parallel issue which has arisen in my own work as a statistician. I have been involved in a number of surveys which deal with the Aboriginal community in Australia. Statisticians have a priority in defining properly what they are measuring, so the issue of "who is an Aboriginal?" is critical. The standard definition is that "an Aboriginal is somebody who considers themselves to be such and is accepted as such by the community in which they live". This is perhaps the best guide that we have in the Geostatistical Association of Australasia. A geostatistician is somebody who considers that they work in geostatistics and is accepted as such by others who they have contact with.

Science and learning has numerous examples of ideas developed in one area being productively applied in others. Much of the mathematical theory which is used in what is commonly called geostatistics was originally developed by statisticians and economists when working with economic time series. Geostatistical computer packages developed for mining applications have been applied to environmental problems. The future will provide further examples like these. While I am hesitant to give forecasts (forecasting is always difficult, especially when applied to the future) I suspect that many of the techniques of spatial classification developed by the environmentalists and image analysts may be productively applied by geologists to the classification of ore types. The "errors in variables" theory used by econometricians with time series data may well be applicable to multivariate spatial data.

Hence our concept of "geostatistician" should include persons who are buying geostatistical techniques to environmental problems. It should include geologists and geochemists who do a significant amount of statistical interpretation of the data they encounter. It should include theoretical statisticians working in spatial statistics. It should include geographers who have developed spatial techniques from a variety of areas and applied them to human populations.

My own experience as a statistician continues to bear this out. I find that the definition of a statistician is best made in terms of an approach to solving problems. It is an approach which aims to extract the maximum amount of information out of available data while at the same time maintaining a high degree of integrity in its use. I sometimes use the term "a quantitative skeptic".

To me this suggests that the membership of the Geostatistical Association of Australasia should be open to a wide audience. While it seeks to publicise and promote the use of a certain range of techniques, it must not become restrictive or overly protective, saying that only those techniques should be used. It must promote a spirit of enquiry and be willing to listen as well as to educate.

I opened this article with several questions and I am closing leaving them barely answered. Complete answers run the risk of restricting our thinking when we have a subject which is evolving rapidly.

The client in the field will never be deeply concerned with a definition of geostatistics. He or she is only concerned with whether or not it helps. As an association, I suggest that it is our role to ensure that what is promoted under the name of geostatistics genuinely does help.

John Henstridge, Data Analysis Australia, email john@daa.com.au


The use of semivariograms in practice

In the previous Newsletter, we reported on a question raised by Jim Weekes from Tom Price on the practical use of the semivariogram and the definition of search parameters. Jim pointed out that there are different schools of thought on this topic. The Kalgoorlie meeting also emphasised the need that exists among many "starting geostatisticians" on how to interpret and use the various semivariogram parameters. Who is willing to take this subject "by the horns" and write on it in our next Newsletter? Please email Louis Voortman on lvoortman@snowdenau.com or John Vann on eoval@ozemail.com .


Revision of the JORC Code

Both in a recent AusIMM Bulletin and AIG News, you might already have noticed several references to further changes and the ‘continued evolution’ of the Australasian Code for Reporting of Identified Mineral Resources and Ore Reserves (‘JORC Code’). In the important international publication Mining Magazine, a review recently appeared on the increased international drive for a "consensus international code" for reporting of resources and reserves. The Australian JORC Code is seen by many as a good example of how this should professionally be organised and therefore is increasingly in the world news. All practising geostatisticians in the mining industry should take a very direct interest in these developments and GAA should play a role in channelling our ideas and suggestions to members of the JORC. John Vann, of course, has been a member for a while already and has compiled a series of notes for your information. (Also see the important remarks on quality control for resources, quality of interpretation and confidence, by Brian Davis, Senior Resource Geologist, GCM Ltd, in the 2nd Newsletter of July 1997). GAA is therefore organising a "presentation-discussion-workshop" on Wednesday 29 October at 5 pm in the QV1 Level 2 Lecture Theatrette, consisting of three presentations on the revisions of the JORC Code by John Vann, Julian Barnes and Ian Glacken. (Ian plans to e-mail a synopsis of the contents of the presentations to all GAA members just before the meeting.)


Second Perth Meeting: Environmental Applications

Due to time constraints, a description of the first environmental talk by Dr Geoff Riley on Friday 5 September, 1997, does not appear in this Newsletter. With apologies to Geoff, we will ensure that this is included in the next Newsletter!!


GAA 1997-1998 Executive Committee

John Vann (President) geoval@ozemail.com
Louis Voortman (Vice-President)
lvoortman@snowdenau.com
Julian Barnes (Treasurer)
rsg_perth@rsg.com.au
Ian Glacken (Secretary)
ian.glacken@wmc.com.au
Brian Davis
briand@avi.com.au
Lyn Bloom
l.bloom@cowan.edu.au
John Henstridge
john@daa.com.au
Donna Kelly (Kalgoorlie)
DKelley@kalgold.com.au
Roussos Dimitrakopoulos (Brisbane)
roussos@minmet.uq.oz.au

GAA is represented "in the regions" by Daniel Guibal, Henry Sanguinetti, Jenette and Mike Binns in Sydney, John Cottle and Stuart Masters in Melbourne, Donna Kelly in Kalgoorlie, Phil Agnew in Townsville, Ernest Baafi in Wollongong, Peter Brooker in Adelaide and Jim Weekes in Tom Price. Please contact these people if and when you wish to start your own local meeting!!


CALENDAR OF EVENTS


Membership

There are four types of Membership:

  • Ordinary Membership (full voting rights) annual contribution $ 30.00
  • Associate Membership (no voting rights) annual contribution $ 15.00
  • Student Membership (no voting rights) annual contribution $ 5.00
  • Company Membership (by invitation of the Executive Committee)

Membership forms may also be requested from our secretary, Ian Glacken:
GAA Secretary, PO Box 1719, West Perth WA 6872
email:
ian.glacken@wmc.com.au or gaa@daa.com.au


CORPORATE MEMBERS AND SPONSORS

The Executive Committee of GAA wishes to convey its sincere thanks to the companies who have already accepted Corporate Membership with the new Association and the organisations that have sponsored our meetings. Their support and financial contributions during our start-up phase have been much appreciated!

SNOWDEN ASSOCIATES
GEOVAL
RESOURCE SERVICE GROUP
DATA ANALYSIS AUSTRALIA
GREAT CENTRAL MINES
WMC
KCGM
MIM EXPLORATION
DATAMINE
ARGYLE DIAMONDS


POSTGRADUATE CERTIFICATE IN GEOSTATISTICS
EDITH COWAN UNIVERSITY
Perth, Western Australia
Mount Lawley Campus

This course is available on the Mount Lawley Campus and can be completed in one semester of full-time study (or equivalent part-time).

The course is aimed at providing the theory and methods for the statistics and mathematical modelling used in the analysis of spatial data. Such data arise as a matter of course in the earth and environmental sciences and this course is of particular relevance to workers in the mining industry.

For further information, please contact the Course Coordinator:
Dr Lyn Bloom
School of Computer, Information and Mathematical Sciences
Tel: (08) 9370 6360
Fax: (08) 9370 6197
email:
l.bloom@cowan.edu.au


BOOK REVIEW
"Geostatistics for Environmental and Geotechnical Applications"
(Rouhani et al., editors)
Published by ASTM, ISBN 0-8031-2414-7, 1996 (280pp)

This book contains papers presented at the symposium of the same name held in Phoenix, Arizona, on 26-27 January, 1995.

The first four papers are grouped in a section entitled "Overview Papers" and they give a good introduction to geostatistics for non-specialists as well as an overview of the application fields for mining and petroleum geostatisticians. In particular, the papers by Marc Cromer ("Geostatistics for environmental and geotechnical applications: A technology transferred") and Mohan Srivastava ("Describing spatial variability using geostatistical analysis") are well targeted.

The fourteen papers in the main paert of the book escribve a range of case studies of environmental, geotechnical and geophysical applications of geostatistics. About 80 percent deal with environmental contamination or hydrogeological problems, only two papers are on strictly geotechical subjects.

Often in an environmental problem we have a limited number of samples in comparison with a mining study. The importance of spatial/temporal variability in environmental studies means that geostatistics has to be used for analysis and mapping of the variables of interest. Environmnetal problems are well-suited to the application of geostatistical methods, as is demonstrated by the many case studies in this volume.

The papers briefly present descriptions of the main geostatistical methods used including ordinary kriging, simple kriging, cokriging, indicator kriging and simulation. The book is interesting for environmental professionals who are contemplating (or already applying) geostatistical methods, as well as giving geostatisticians working in non-environment fields a good overview of this growing area of application. A good selection of references has been provided for each paper in the volume, allowing environmental specialists to get up to speed in geostatistics quickly.

In summary, the papers presented are of general interest to those currently involved in geostatistics, but specially valuable to workers in the field of environmental applications. This collection demonstrates that the geostatistical approach can be succesfully applied with a professional environmental insight to provide optimal solutions to contamination, soil science and water quality problems.

Reviewed by Tatiana Skvortsova, Geoval, email geoval@ozemail.com.au


CALL FOR PAPERS
"WHY BUSANG OR JOSH COULD NOT HAPPEN IN AUSTRALIA"

The Western Australian Branch of the Australian Institute of Geoscientists is holding a one-day seminar in Perth on Friday 12 June 1998. A call for papers has been published in the AIG News of August 1997. Please see this publication for more details or contact Brian Davis at (08) 9327 8211 and Peter Kitto on (08) 9313 2044.

The subject undoubtedly is of much interest to geostatisticians and GAA urges its members to contribute, especially on sampling, sample quality control, sampling methods and innovations, sampling error and sample accountability in grade control and reconciliation.


GEOSTATISTICAL SIMULATIONS FOR THE MINING INDUSTRY:
Tools for Enhancing Metal Recovery and Mine Profitability
Brisbane, October 20-22, 1997

Who should attend

Mining engineers and geologists interested in geostatistical simulations and profitability driven decision making tools for mining applications.

Objectives and Content

Understand how to deal with grade and tonnage uncertainty and variability
Present new profitability based simulation methodologies for enhancing metal recovery
Provide industry examples and experiences at different stages of a mining project
Provide hands-on computer experience using data sets from actual case studies

Geostatistical simulation techniques provide the means to assess orebody grade and tonnage variability in the context of risk assessment and maximum profitability, and in various stages of a mining project. Geostatistical simulation techniques form the basis for decision making tools when grade variability and spatial orebody complexity are the critical factors. This short course introduces a new framework for enhanced metal recovery and mine profitability based on a collection of new conditional simulation techniques and optimisation principles. Emphasis is placed on the effective, efficient and practical solutions that conditional simulations offer today to the mining venture, as well as concept understanding through practical examples. Examples include gold, base metals and coal deposits.

Course Outline

The course begins with an introduction to a general simulation based framework and current mining practices, and continues with: (i) an overview of basic geostatistical concepts; (ii) nuts and bolts of main simulation algorithms; (iii) applications and intricacies in the areas of resource assessment and classification; recoverable reserves and selectivity; additional drilling programs; pit design and scheduling; grade control and ore classification; scheduling sensitivity and mill feed variability; and (iv) computer workshops.

Invited speaker is Ian Glacken, Manager - Ore Reserve Systems, Nickel, WMC Resources Ltd.

Introduction

Frameworks for uncertainty, profitability, optimisation and mining operations
Simulation - mining transfer functions - optimisation

Basic Concepts

An intuitive introduction to Monte Carlo simulation; risk assessment with examples
Mining data analysis, variograms and spatial continuity
Grade estimation approaches

Geostatistical Simulations for Mining

Simulation algorithms: sequential, LU, fractal, P-field
Applications: nuts and bolts
Post processing of simulation results: A problem dependent approach
Resource assessment and classification
Grade control, classification, and 'dollar'-optimal mining parameters
Mill feed variability
Mine planning

Computer Workshops

Grade control in a gold mine: case study

Course Lecturer

Roussos Dimitrakopoulos is currently Professor and Director of the WH Bryan Mining Geology Research Centre at The University of Queensland. He holds a PhD in Geostatistics from Ecole Polytechnique, Montreal, where he studied under Professor M. David, and a MSc in Geostatistics from the University of Alberta, Edmonton. He has been working in Geostatistics since 1983, both in applications as well as the development of stochastic simulation techniques. He has been a Senior Geostatistician with Newmont Gold Co., Denver, a Senior Consultant with Geostat Systems Int., Montreal, and a geostatistics professor at McGill University, Montreal. He is a member of AusIMM, CIMMP, IAMG, and has taught short courses in North America, South America, Europe, the Middle East, Japan, and Australia.