Silicon Dale

The Russian system of resource/reserves classification

Following last month's column, I have been prompted to write this in explanation of a system which - to many - seems at odds with the evolving international systems of resource/reserves classification. Anyone who has worked on deposit modelling or mine planning in the former Soviet Union, or in much of eastern Europe, or indeed anywhere else in the world where Russian geologists have been active in the past half century, will be familiar with the so-called 'reserves' categories A, B, C1, C2, and 'prognostic resources' P1, P2, and P3. Since these are defined without regard to the economics of actually mining the deposits concerned, all categories must be regarded as resources, not reserves. A useful simplification is to consider categories A and B as equivalent to measured resources, and category C1 as an indicated resource. C2 is then an inferred resource (in which some material of P1 might sometimes also be included). The 'P' categories are largely wishful thinking and have no equivalent in the western national or the CMMI international classifications. The UNFC does, however, include a category of 'reconnaissance mineral resource' which may correspond to one or more of these.

In fact, the Russian system embraces much more than simply classification of resources or reserves. It is a fully integrated system of exploration, mine development, and reporting, in which there are clear definitions at each stage, controlling (among other things) drilling grid spacing, methods of computation of resource tonnage and grade, cutoff grades to be applied, and how mining losses and dilutions are to be computed. All is specified in Soviet law, which has been inherited by the various independent republics. It is backed up by a set of regulations on mineral exploration and mining licences. There is no room for uncertainty in the Russian system, which means that once a resource is defined and agreed within the scope of a mining licence, the resource must be fully extracted and the defined royalties paid. The defined resource is known as the 'balance' ore, and is automatically reduced with each annual production report. There is also provision for marginal or low-grade material, known as 'out-of-balance' ore, and on which normally a lower rate of royalty is payable. If some of the computed balance ore is found not to exist, then it may be possible for the mine operator to make up the difference from 'out-of-balance' ore and avoid penalties which might otherwise be payable. This is the way the system operates in Russia, but it is still the same in most of the republics, with differences only of detail, and in the licensing procedures (closed or open competition, invited tenders, etc).

At the exploration stage, drilling grids are defined for different types of deposit and for the different categories of resource. A very useful brief English-language summary is given by Sergei Diatchkov in Mining Engineering, March 1994, p.214-217. However, he does not include any detailed description of the computational methods which are used. It remains a requirement in Russia that official resource reports are based on simple sectional interpretation, with prismatic and pyramidal interpolation between sections to generate the resource figures. The exact methods of computation in all circumstances are pre-defined in a 'cook-book' which allows the resources in even a highly complex deposit to be computed manually (though in practice there are now a number of computer programs to reduce the tedium of the task). Because this set of methods is also controlled by the same regulations, the introduction of geostatistical modelling for mining in Russia has been a very slow process. However, I am not aware of any English translation of the cook-book, nor does it seem likely that it will be translated, since the methods documented have long since been superseded in the west. The result is that the western geologist is faced with a 'black box' when confronted with Russian resource figures.

When building a geological database from existing Russian data, it is commonly found that a large amount of data is provided - though sometimes only after repeated requests (for example, building and validating the geological database for the Suhoi Log gold deposit in 1995-6 took us, altogether, nearly two years). Russian geologists tend to be meticulous in their work - partly from natural conscientiousness, and partly because every set of records is double-checked. However, upon examination of these records, it is very common to discover that for some reason there are no assays below a pre-defined cutoff grade. This is because the data which are filed with the authorities, and form the official record, are only those directly used to define a resource - i.e. those which lie within the boundary of an orebody. And that boundary is controlled by a specified cutoff grade. Assays not included in these files - if they survive - may sometimes be found in the vast sets of box files archived in local or regional geological exploration or mine design institutes.

It is also commonly found that the available geological data are supplied without drillhole location coordinates and without downhole survey data. It may seem incredible, but full grid coordinates still remain secret in Russia, and there is often some reluctance to supply local mine coordinates or even plans with scale bars. Published data invariably lack coordinates or scale information. Downhole survey data must often be extracted from the plotted drillhole traces on sections and plans. Obviously there is substantial scope for error, both in transcription and in digitising or measurement from paper plans.

In short, the Russian system of resource classification is logical, practical, and has much to recommend it. However, it is integrated so throroughly with the geological methods and practices which crystallised in the Soviet era (the 1950s and 1960s) that nothing short of a total replacement will suffice to update it. Inevitably, I believe, this will involve the adoption of a version of the international classification system. While that might be seen as a good thing, nevertheless there are some babies which will be thrown out with the bathwater - in particular the linkage of specified drill spacings with resource categories, and the integration of methodologies from exploration through mine production and the computation of reconciliations.

Stephen Henley
Matlock, England

Copyright © 2000 Stephen Henley
The Russian system of resource/reserves classification: Earth Science Computer Applications, v.15, no.12, p.1-2