Radio frequency tomography trial at Mt Isa Mine

Zhou, Binzhong; Fullagar, Peter K.; Fallon, Gary N.

doi:10.1071/eg998675

Cited by 24 publications

(10 citation statements)

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“…After the discretization of the borehole section into rectangular cells, the measured amplitudes are converted into the attenuation distribution using a data reduction step [11,[35][36][37][38]. In the EMRE system, the output power is not monitored, but the unknown source strength can be estimated by a linear regression of reduced amplitudes in a homogeneous medium [39], and the global value is automatically calculated. In a homogeneous environment, a global source strength can be used for all transmitter positions.…”

Section: International Journal Of Geophysicsmentioning

confidence: 99%

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Characterization of Geotomographic Studies with the EMRE System

Korpisalo

2014

International Journal of Geophysics

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Posiva Oy carries out research and development on spent nuclear fuel disposal in Finland. The repository will be constructed deep in the crystalline bedrock of Olkiluoto island in Eurajoki. Posiva Oy and ANDRA (France) have cooperated actively in examining methods for revealing properties of granitic bedrock. One of the considered methods was an electromagnetic cross-borehole survey, and RIM measurements were conducted in 2009. Olkiluoto migmatitic bedrock has undergone polyphasic ductile-brittle deformation and resistivity in the bedrock varies strongly in range of tens to tens of thousands of Ωm. Field work was successfully performed in one borehole pair. The results are presented in this paper. The tomographic reconstruction of the borehole section is based on the far-field approximation of the electric field. The results prove that the method can be used between boreholes to delineate and follow sulphide-bearing horizons. The detected low and high resistivity zones and their apparent shapes and orientations are in fair agreement with geological and other geophysical results. The obtained information can be used, for example, in assessing the integrity of the rock mass, as the increased electrical conductivity is often associated with rock mass deformation (clay and water bearing fractures, sulphide and graphite bearing zones).

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Section: International Journal Of Geophysicsmentioning

confidence: 99%

“…The attenuation distribution can be converted to the conductivity distribution (S/m) using an equation presented by [39]:…”

Section: International Journal Of Geophysicsmentioning

confidence: 99%

Characterization of Geotomographic Studies with the EMRE System

Korpisalo

2014

International Journal of Geophysics

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“…Resistivity and dielectric constant are usually much more interpretable to geologists and mining engineers than velocity and absorption. Given values of a and V. it follows from (1), (2), and (3) that the conductivity a (or resistivity p) can be expressed as 1 2a (4) p /IV were computed from the recorded amplitudes after correction for the first three effects (Zhou et al, 1998).…”

Section: Multi-parameter Reconstruction Of Radar Tomographic Datamentioning

confidence: 99%

<title>Borehole radar conductivity and permittivity tomography</title>

Zhou

Fullagar²

2000

SPIE Proceedings

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Velocity and absorption tomograms are the two most common forms of presentation of radar tomographic data.In this paper a simple transformation is developed, to convert velocity and attenuation coefficient to conductivity and dielectric constant. The approach is illustrated via application to data from the Hellyer zinclead-silver mine, Tasmania. The conversion to conductivity and dielectric constant was especially advantageous because mining personnel, geophysicists included, are often unfamiliar with radar velocity and absorption. Encouraging results were obtained in mapping the distribution of electrical properties between boreholes at Hellyer, illustrating the potential of radar tomography to delineate sulphide ore zones.

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“…A straight-ray approximation has been commonly adopted for radio tomography. The validity of the approximation was discussed in depth by Dines and Lytle (1979) and has been tested in practice (Dines and Lytle, 1979;Cao et al, 1995;Zhou et al,1998;Fullagar, et al, 2000).…”

Section: Conductivity Tomography At Two Frequenciesmentioning

confidence: 99%

Conductivity tomography at two frequencies

Cao

Zhu

et al. 2003

GEOPHYSICS

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We present a new approach for crosshole radio tomography. Conductivity images of the investigated area are reconstructed from the ratio of the electric field intensities measured at two similar frequencies. The method largely avoids assumptions about the radiation pattern and in-situ intensity of the transmitting antenna, which introduce errors in conventional single-frequency crosshole electromagnetic-absorption tomography. Application of the method to field data achieved an improvement in resolution of anomalies over traditional single-frequency absorption tomography. The dualfrequency method is not a universal approach; it is suitable for moderately conductive media (>0.01 S/m) over the approximate frequency range 1-100 MHz.

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Radio frequency tomography trial at Mt Isa Mine

Cited by 24 publications

References 1 publication

Characterization of Geotomographic Studies with the EMRE System

Characterization of Geotomographic Studies with the EMRE System

<title>Borehole radar conductivity and permittivity tomography</title>

Conductivity tomography at two frequencies

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