The Arizona Appraisal System is a totally integrated methodology that uses a series of interactive computer programs to translate subjective geologic opinion into a probabilistic estimate of mineral endowment. By "totally integrated methodology" is meant a unified, conceptually complete approach. This methodology comprises two main sections, each executed on a different computer system. The first section, the Geologic Decision Model, has been computerized as an interactive PLATO program. Using the PLATO system, the geologist describes probabilistically the perceived states of geologic processes and conditions. The decision model analyzes this information and computes a probability distribution for mineral occurrence. The second section, the Endowment Simulation Model (program MASTER), is run on the DEC 10 and Cyber 175 computers. Program MASTER takes the product of the Geologic Decision Model, combines it with other data, and produces a probabilistic estimate of mineral endowment for the region being evaluated. Development and testing of the Arizona Appraisal System were carried out simultaneously over a period of about three years. During this period, four geologists from government and industry were called upon four or five times over a period of about a year for a study of the uranium (U₃O₈) endowment in the San Juan Basin of northwestern New Mexico. The results produced by the system consist, for each geologist, of a probability distribution for tons of U₃O₈ endowment for (1) each partition of each stratigraphic unit, (2) each stratigraphic unit as a whole, (3) "formations" or "merged units" (groups of stratigraphic units), and (4) the San Juan Basin as a whole (all stratigraphic units). The system also calculates the average distribution across all geologists for the various merged units and for the basin as a whole. The result for the basin as a whole (in thousands of tons) is: mean 3,855, variance 4,108 x 10⁹, and 95th percentile 6,541. The author believes that his major contribution has been to design and implement a working resource estimation methodology that is flexible with respect to commodity and geographic location.

M.Sc. (Geology) / Please refer to full text to view abstract

SP, resistivity/IP and seismic refraction responses of the Woodlawn Orebody and Mt.Bulga Deposit are examined and compared. Both exhibit similar responses produced mainly by uneconomic and disseminated sulphide mineralization and host rock features, demonstrating that the magnitude and character of electrical and seismic responses are not reliable indicators of size and economic sulphide content of volcanogenic sulphide ores. SP, soil geochemistry and electrogeochemistry are found to be the most effective exploration methods followed by resistivity/IP and seismic refraction. The large SP responses over both ore zones are simulated using new methods which allowed the width and depth of oxidation to be computed. Conventional and compensation array resistivity responses best define the deposits. Computer simulation shows that dipole- dipole and Unipole arrays are most useful. First order IP responses are large and similar, but the ore zones are not easily distinguished from polarizable host rocks. Second order responses, at Woodlawn, better define these lithologies and cross-plots of EM coupling removed first order parameters prove useful. The supergene and gossan zones are defined as sources of electrical anomalies and correlate with interpreted SP sources. Seismic velocities of fresh Woodlawn ore samples indicate only small contrasts with host rocks. Refraction travel-time data are highly complex but host rocks are clearly distinguished by their seismic velocities. Both deposits appear as low velocity zones at the general bedrock level which are shallower and narrower than the electrical sources associated with the ore zones. Extensive model simulation shows that the Reciprocal interpretation method is most useful when compared to other time- term methods for refraction interpretation but has some limitations. Computer simulation shows the significance of non- critical refractions, diffractions and laterally hidden zones which define the lateral resolution of the refraction method. The results of this study and the interpretative techniques developed will assist the exploration for similar and deeper massive volcanogenic orebodies in comparable geological environments.

The profitability of a mineral deposit can be concluded by the comparison of net present values (NPV) of all revenues and expenditures. In the estimation of NPV of a mineral deposit, many parameters are used. The parameters are uncertain. More accurate and reliable NPV estimation can be done with considering the related uncertainties. This study investigates the probability distributions of uncertain variables in estimation of NPV and evaluation of NPV using Monte Carlo simulation. @Risk 4.5.7 software package is used to apply Monte Carlo simulation method. At the end of the study, all possible net present values and their probabilities are given as a probability distribution. Derek&ouml / y copper ore reserve is selected to apply uncertainty assessment in NPV of ore reserves. The reserve is evaluated using both conventional polygonal method and a mining software which is Micromine. The southeastern part of the reserve was selected as a study area because average grade of the reserve is relatively low and the reserve extends to a larger area. At the end of the assessment, NPV of the southeastern part of Derek&ouml / y ore reserve was found to be between $77.97&times / 106 and $318.78&times / 106 with 68.27% (x&plusmn / &amp / #963 / ) probability and between &ndash / $45.37&times / 106 and $443.54&times / 106 with 95.45% probability (x&plusmn / 2&amp / #963 / ).

In the recent years, ongoing debates in the mineral sector has shown that efficient use of natural resources is of vital importance as the use of minerals is essential for modern living. Especially, in the context of sustainable development, it is required that mineral resources should be exploited to maximize the contribution to the well being of current generation without depriving the potential for future generations to meet their own needs. The aim of this thesis is to develop a decision support system using system dynamics methodology where

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Thesis (Ph.D.)--McMaster University (Canada), 1988. / Source: Dissertation Abstracts International, Volume: 62-13, Section: A, page: 0000.