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Thesis (M. Sc.)--University of Adelaide, Dept. of Economic Geology, 1985. / Includes bibliographical references (leaves 48-51).

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Development work in the field of mineral borehole logging was made in the areas of instrumentation, field testing, data processing and interpretation. / Instrumentation work included a VLF logging tool compatible with a field digital computer configured to perform log instrumentation control, numerical data acquisition and recording together with video screen graphic display. Significant improvements in the overall precision and reliability of the logging operation has been realized through the use of digital technology. / The field tests included the measurements of the following parameters: electrical resistivity, induced polarization, spontaneous polarization, electromagnetic field ratio and phase difference and temperature. The tests were performed for a wide variety of environments and targets including massive and disseminated sulfides, structural problems, coal and gold fields on properties located in Eastern Canada from Sudbury to Cape Breton Island. / The interpretation of the data yields information complementing core information such as detection of materials with some electric property contrast, localization of off-hole mineralization both in massive and disseminated form and determination of absolute value of specific in-situ rock physical properties. A better understanding of several underground processes (such as SP, uniform field induction, etc.) has resulted from the project.

The piezoelectric effect of quartz rich rock has been investigated both in the laboratory and a subterranean environment. In the laboratory experiment, rock specimens from the Con Mine, Northwest Territories, were examined for crystal alignment and cut into oriented 3.81 cm (1.5 in) sided cubes. The specimens were clamped, together with the measuring electrodes, between parallel plates of a compression cage designed to apply a consistent and uniform pressure distribution across the samples. A solenoid device applied a stress pulse of highly repeatable amplitude and form to the specimen and an instrumentation amplifier measured the differential piezoelectric voltage between opposite faces of the specimen. The massive samples with random fabrics were expected to yield a net "statistical effect". The measured voltage variations between orthogonal directions were attributed to signal domination by large crystals within the matrix, limited sample volume, microfracturing, and the distribution of non-piezoelectric mineral components within the matrixes of some specimens. The greatest piezoelectric responses were obtained from samples containing large crystals in their matrix. The cubic aggregates which clearly exhibited quartz crystal alignment displayed the theoretically predicted minimum piezoelectric response parallel to the preferred crystal elongation direction. The specimens exhibiting greatest alignment produced the largest piezoelectric responses. The limited experimental evidence indicated that the signal magnitude was also proportional to quartz content and crystal size. Underground trials of two exploration systems were conducted at the Con Mine In the first trial, during periods of low industrial electrical interference, clear piezoelectric signals were observed for source-target distances as large as 55 m and electrode-target distances out to 20 m. Piezoelectric signals were generated by impact of both compressional and shear seismic waves with the exposed quartz vein. While this exploration system operated quite effectively during periods of low electrical noise, a superior filter system was required for the normal conditions. For the second fields test, a more portable, DC powered, instrumentation amplifier with an extensive filter system was designed. Despite the improved filtering, noise levels were significantly higher during this trial and beyond 10 m the initial arrival of the piezoelectric signal was obscured. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1949. / Vita. The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed July 12, 2010) Includes bibliographical references (p. 50-51).

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