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A discovery-process model that had been devised previously to estimate the size distribution of oil and gas fields remaining to be discovered in a single producing horizon was adapted to a basin containing spatially connected multiple plays and producing horizons. This model used the concept of the area of influence of wells to estimate search effort. Other variables estimated from the historical drilling and discovery data are the effective basin size and the exploration-drilling efficiency. Data from the Midland Basin are used to illustrate how the model works. [ABSTRACT FROM AUTHOR]

An abundance model resource appraisal has been undertaken for 10 mineral commodities in Canada: nickel, copper, zinc, lead, molybdenum, uranium, silver, gold, chromium, and tin. The purpose of the appraisal was to investigate the applicability of the model to the Canadian situation. Resource appraisals for the first 6 of the commodities studied have been published following deposit modeling studies. For many other commodities studied have been published following deposit modeling appraisals. The demonstration of the relevance of the abundance model to Canada would allow its application in such cases. The data presented in this paper indicate that the approximate relation, resource (short tons)=abundance (%)×10. holds true for all commodities studied except chromium and tin. As the resources versus abundances relationship observed on a global scale is observable in Canada, it is concluded that Canada is a sufficiently large fraction (∼7%) of the earth's continental crust to represent a valid sample of that crust. Canada appears to be relatively well endowed with resources of copper, molybdenum, lead, and zinc, and poorly endowed with chromium and tin. It is proposed that the intersection of national boundaries with the boundaries of the world's metallogenic provinces is of greater importance than the intensity of past search, a feature that has been suggested in other studies. If these areas overlap, a nation may be self sufficient in a commodity: if they do not, the nation must import, or find a nationally available substitute. The sources of information used in the appraisal are outlined together with an analysis of the problems encounterea and the time requirements. [ABSTRACT FROM AUTHOR]

The Geological Survey of Canada (G.S.C.) has been involved in national appraisal of resources of certain commodities for nearly two decades beginning with a national study of iron deposits in 1955. In 1972, the first national appraisal to rapidly estimate 'total' resources of Cu, Pb, Zn, Ni, Fe, Mo, and U in Canada was carried out largely by economic geologists. This exercise produced, among other things, a better definition of G.S. C. needs for building computer files in support of mineral deposits studies and mineral resource appraisal. Objectives of this paper are threefold: (1) to outline general methodology for the kind of mineral resource appraisal carried out by the G.S.C. in 1972; (2) to identify types of information required in that appraisal; and (3) to indicate types of information on mineral deposits for which it seems advantageous for the G.S.C. to construct computer files, and how these files relate to mineral resource appraisal. Methodology is fairly straightforward for appraisal of reserves (known, measured resources), but is much more problematic for appraisal of undiscovered resources. For the latter, G.S.C. economic geologists make use of two basic concepts: the 'deposit model,' which is a generalized deposit type, distinguished by its geological attributes and host rock environment, and containing characteristic amounts of specified commodities; and the 'metallogenic region,' which is a geographic area of more or less homogeneous geology deemed favorable for the presence of a particular deposit model. Background information required for appraisal of undiscovered resources includes the following: (a) data on distribution and geology of Canadian deposits and occurrences; (6) data on geology of important, foreign deposits; (c) knowledge of Canadian geology, commensurate with metallogenic requirements; (d) knowledge of current theories of ore-forming processes; and (e) appreciation of the amount, location, and effectiveness of past exploration in Canada. At present, only identity, location, and certain simple geological features of Canadian deposits are considered practical for a general computer file of mineral deposits. The fundamental activity of the G.S.C. in the sphere of mineral deposits is a number of broad studies on the geology of certain commodities in Canada carried out by economic geologists. Appraisal of mineral resources is based directly on the results of those studies, and is done by the same economic geologists. Construction of G.S.C. computer files is in response to needs defined by economic geologists, mainly in the context of their broad studies. [ABSTRACT FROM AUTHOR]

General principles in evaluation and selection of data to be included in computer processible files intended for use in assisting regional resources appraisal are discussed against the background of activities related to file assembly at the Geological Survey of Canada. Some of the principles discussed are currently being implemented in the assembly of files at the GSC where they apply to the specific data being collected. Others are apparent from our analysis and would be applied if different data were being collected. The files currently being assembled at the Survey are intended to assist the commodity geologists in all project-related activities, one of which is regional resource appraisal. Prior to the commencement of data assembly, each data item considered for inclusion in the data files was scrutinized by members of the Economic Geology Subdivision in order to establish how it would contribute to the overall objectives of the file. At the same time strict definitions of each item were established. The main criteria applied to each data item considered for inclusion in the files were (a) the necessity of the item to satisfy the objectives of the file within the practical limitations of the resources available and (b) the general availability of the item. The characteristics found necessary to ensure integrity of the data files were (a) uniformity-the same definitions must apply to each item of similar type, (b) consistency-analytical results should be of the same method or differences noted in order that the data may be compared, and (c) mutual exclusiveness-especially when dealing with data referring to size. Such data should never be repeated in another part of the file or be included as part of another item. [ABSTRACT FROM AUTHOR]

Construction of a petroleum data file first requires answers to specific questions: Who are to be the users; for what purpose is the file to be used; what are to be the data sources; are proprietary data to be included; is graphic display of the data desired? After fixing these guidelines, attention may be directed to data acquisition and file building. Because many useful software systems are now readily available, this aspect of the file-building process should require little attention. In general, the software should include an open-ended format to permit addition of new data items and easy updating, with economy of space on the tape or lisc. With respect to the data, and unless the file has a narrow usage, all available data on the geological and engineering aspects of petroleum occurrence should be collected. Proprietary data should be avoided, if possible, or else clearly labeled, and the file should be planned for public use, for convenience, to provide a needed service, and to avoid the pitfalls of implied secrecy. [ABSTRACT FROM AUTHOR]

Classification of nonfuel mineral reserves is the prime function of the Bureau of Mines Minerals Availability System (MAS). The MAS classifies reserves through geologic, engineering, and economic evaluation of presently identified resources. The classification of a reserve is accomplished by calculating the identified-resource availability in terms of present and prospective prices (costs). The availability of mineral supplies is definable as a function of natural physical phenomena, industry technology, costs, capital generation, time requirements, supply site infrastructure, mineral-land accessibility, environmental restraints, and political conditions. These and other criteria are being systematically evaluated and quantified in the MAS to arrive at verifiable estimates of present and future United States mineral reserve positions. The MAS is structured such that mine and deposit evaluations form the common denominator of supply, and costs represent the basic mechanism of supply analysis. A comprehensive, systematically structured minerals evaluation system is needed to objectively assess mineral supply impacts on the economy and society. The MAS is an element of that capability wherein a systematic unraveling of the mineral supply network is performed, with the results structured in electronic retrieval format for rapid listing, manipulation, and supply analysis. The key activity in accomplishing this end is the mineral deposit evaluation process that provides uniform, maintained information sets for aggregation into summary products. The MAS thereby enhances the basic data and response capability to support mineral specialists, mineral policy analysis, and the Government and industry decision process. [ABSTRACT FROM AUTHOR]

Exploration geochemistry is viewed in a resource appraisal framework and the various general methods are discussed in terms of their applicability at different stages of the appraisal exercise. The direct nature of geochemical exploration is emphasized and the various types of data that the surveys yield are discussed together with their modes of interpretation. It is shown how the data may be simply reduced to a probability form which will allow data from many sources to be utilized. The limitations of exploration geochemistry in resource appraisal are also discussed so that unnatural expectations may not be fostered and that geochemistry be placed correctly, and complementarity, with the other geoscience techniques of resource appraisal. [ABSTRACT FROM AUTHOR]

The ever-increasing world interdependency required to provide the basic energy and mineral commodities needed by society, has created a need to assess, on a common basis, the location, number, and quality of deposits of natural resources. In order to evaluate and compare the resource potential of any area, two major factors must be considered: (1) the type of commodity being evaluated and (2) the specific parameter (reserves or resources) which is being defined. Each commodity or parameter being studied requires a separate methodology for analysis and different basic data. Porphyry copper deposits must be treated differently from stratabound copper deposits or massive sulfide deposits of copper. Similarly, oil and gas deposits associated with stratigraphic traps must be treated differently from those associated with salt domes. Resource assessments attempt to estimate the aggregate resource potential of an area whereas resource analyses attempt to define the specific characteristics of the individual occurrences which comprise the aggregate resource potential. Assessment programs may range from a national inventory of known deposits and occurrences to detailed studies which require an extensive integration of geological, geochemical, and geophysical data. Examples of national inventories are the small mine inventory of Bolivia and presently operating resource programs in Turkey and Argentina. Detailed programs of assessment include the AMRAP (Alaska Mineral Resource Appraisal Program) program and studies in the Coeur d'Alene district and Ely, Nevada. Worldwide resource analysis is a rapidly expanding field of endeavor necessitated by the need to more clearly define the characteristics of known deposits and to provide quantitative estimates of hypothetical and speculative resources. Studies presently underway deal with the development of search and occurrence models, field size distributions of energy resources, tonnage and grade relationships of mineral deposits, the zone of influence of exploratory drill holes, and models of the exploration process. [ABSTRACT FROM AUTHOR]

This short paper summarizes the International Geological Correlation Program (IGCP) and shows how Project 98-Standards for Computer Applications in Resource Studies-relates to this program. [ABSTRACT FROM AUTHOR]