Mineral deposit signatures by borehole geophysics: data from the borehole geophysical test site at the McConnell nickel deposit (Garson Offset), Ontario

Killeen, P G; Mwenifumbo, C J; Elliott, B E

doi:10.4095/203744

Cited by 6 publications

(7 citation statements)

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“…The sulphides (pentlandite, pyrrhotite, and chalcopyrite) occur as 1 to 2 cm blebs within the quartz diorite, but mainly as disseminated sulphides in the surrounding breccia. The McConnell deposit, located upon INCO Ltd. property, is representative of the nickel deposits of the Sudbury area (Killeen et al, 1996).…”

Section: Local Geologymentioning

confidence: 99%

“…The Geological Survey of Canada (GSC) has measured the borehole geophysical signatures of a variety of ore deposits as part of a project jointly funded by the federal and provincial governments in the Northern Ontario Development Agreement (NODA) (Killeen et al, 1996).…”

Section: Borehole Investigationsmentioning

confidence: 99%

“…Borehole intersection and surface mapping imply a deposit geometry that is tabular with a strike length of approximately 152 m and a depth extent of 610 m (Killeen et al, 1996). A fence of five boreholes which intersect the deposit (Fig.…”

Section: Borehole Investigationsmentioning

confidence: 99%

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Combined 3‐D Interpretation of Airborne, Surface, and Borehole Vector Magnetics at the McConnell Nickel Deposit

Mueller¹,

Morris²,

Killeen³

et al. 1998

JEEG

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The McConnell nickel deposit is an elliptical amphibolite-biotite quartz diorite pod within the Sudbury Metabreccia that surrounds the main mass of the Sudbury Igneous Complex. The geometry of the deposit is tabular with a strike length of approximately 152 m and depth extent of 610 m. Various magnetic surveys were conducted in this study area. A regional aeromagnetic survey was conducted by the Ontario Geological Survey. A more detailed ground magnetics survey and a borehole magnetic survey are used in the interpretation of the character of the causative body. Five boreholes which intersect the deposit at 40 m, 105 m, 135 m, 210 m, and 250 m provide good lithological control of the deposit with depth. Eight other boreholes used in this study did not have logged lithology, but all 13 holes were logged with gamma ray, density, spectral gamma-gamma, IP, resistivity, SP, magnetic susceptibility, temperature, and 3-component magnetic field probes. Only the measurements of magnetic susceptibility and 3-component magnetic field measurements and their interpretation will be discussed in this paper. 3-component magnetic vector surveys show different signatures for boreholes that pass through a magnetic source body (an onhole source), and for holes that are adjacent to the source body (an offhole source). Using inverse models of the surface magnetic data, values of magnetic susceptibility and magnetic remanence direction and intensity for the various lithological units are estimated. Modelling of the subsurface data reveals fine structure within the ore body and may be used to estimate the direction and distance to other offhole magnetic bodies.

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Section: Local Geologymentioning

confidence: 99%

Section: Borehole Investigationsmentioning

confidence: 99%

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Combined 3‐D Interpretation of Airborne, Surface, and Borehole Vector Magnetics at the McConnell Nickel Deposit

Mueller¹,

Morris²,

Killeen³

et al. 1998

JEEG

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show abstract

“…The Geological Survey of Canada (GSC) has measured the borehole geophysical signatures of a variety of ore deposits. This project is jointly funded by the federal and provincial governments in the Northern Ontario Development Agreement (NODA) (Killeen et al, 1996).…”

Section: Borehole Investigationsmentioning

confidence: 99%

Combined 3‐D interpretation of airborne, surface, and borehole vector magnetics at the McConnell Nickel deposit

Mueller

Morris

Killeen

et al. 1997

SEG Technical Program Expanded Abstracts 1997

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The McConnell nickel deposit is an elliptical amphibolite-biotite quartz diorite pod within the Sudbury Metabreccia that surrounds the main mass of the Sudbury Igneous Complex. The geometry of the deposit is tabular with a strike length of approximately 152 m and depth of 610 m. Various magnetic surveys were conducted in this study area. A regional aeromagnetic survey was conducted by the Ontario Geological Survey. A more detailed ground magnetics survey and borehole magnetic survey are used in the interpretation of the character of the causative body. Five boreholes which intersect the deposit at 40 m, 105 m, 135 m, 210 m, and 250 m provide good lithological control of the deposit with depth. Eight other boreholes used in this study did not have logged lithology, but all 13 holes were logged with gamma ray, density, spectral gamma-gamma, IP, resistivity, SP, magnetic susceptibility, temperature, and three-component magnetic field probes. Only the measurements of magnetic susceptibility and three-component magnetic field measurements and their interpretation will be discussed in this paper. Three-component magnetic vector surveys show different signatures for boreholes that pass through a magnetic source body, and for holes that are adjacent to the source body. Using inverse models of the surface magnetic data, values of magnetic susceptibility and magnetic remanence direction and intensity for the various lithological units are estimated. Modelling of the subsurface data reveals fine structure within the ore body and may be used to estimate the direction and distance to the magnetic bodies.

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“…The McConnell sulfide body is shallow, extensively drilled, and close to an operating mine, rendering it an excellent geophysical test site. Prior to the work described here, the Geological Survey of Canada (GSC) had recorded a comprehensive suite of downhole geophysical logs at McConnell (Mwenifumbo et al, 1993;Killeen et al, 1996). The dc resistivities varied over four orders of magnitude, from near zero in the massive sulfides to over 30 000 ohm-m within the breccia.…”

Section: Introductionmentioning

confidence: 99%

Radio tomography and borehole radar delineation of the McConnell nickel sulfide deposit, Sudbury, Ontario, Canada

Fullagar¹,

Livelybrooks

Zhang

et al. 2000

GEOPHYSICS

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In an effort to reduce costs and increase revenues at mines, there is a strong incentive to develop highresolution techniques both for near-mine exploration and for delineation of known orebodies. To investigate the potential of high-frequency EM techniques for exploration and delineation of massive sulfide orebodies, radio frequency electromagnetic (RFEM) and ground-penetrating radar (GPR) surveys were conducted in boreholes through the McConnell massive nickel-copper sulfide body near Sudbury, Ontario, from 1993Ontario, from -1996 Crosshole RFEM data were acquired with a JW-4 electric dipole system between two boreholes on section 2720W. Ten frequencies between 0.5 and 5.0 MHz were recorded. Radio signals propagated through the Sudbury Breccia over ranges of at least 150 m at all frequencies. The resulting radio absorption tomogram clearly imaged the McConnell deposit over 110 m downdip. Signal was extinguished when either antenna entered the sulfide body. However, the expected radio shadow did not eventuate when transmitter and receiver were on opposite sides of the deposit. Two-dimensional modeling suggested that diffraction around the edges of the sulfide body could not account for the observed field amplitudes. It was concluded at the time that the sulfide body is discontinuous; according to modeling, a gap as small as 5 m could have explained the observations. Subsequent investigations by INCO established that pick-up in the metal-cored downhole cables was actually responsible for the elevated signal levels.Both single-hole reflection profiles and crosshole measurements were acquired using RAMAC borehole radar systems, operating at 60 MHz. Detection of radar reflections from the sulfide contact was problematic. One coherent reflection was observed from the hanging-wall contact in single-hole reflection mode. This reflection could be traced about 25 m uphole from the contact. In addition to unfavorable survey geometry, factors which may have suppressed reflections included host rock heterogeneity, disseminated sulfides, and contact irregularity.Velocity and absorption tomograms were generated in the Sudbury Breccia host rock from the crosshole radar. Radar velocity was variable, averaging 125 m/µs, while absorption was typically 0.8 dB/m at 60 MHz. Kirchhoffstyle 2-D migration of later arrivals in the crosshole radargrams defined reflective zones that roughly parallel the inferred edge of the sulfide body.The McConnell high-frequency EM surveys established that radio tomography and simple radio shadowing are potentially valuable for near-and in-mine exploration and orebody delineation in the Sudbury Breccia. The effectiveness of borehole radar in this particular environment is less certain.

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Mineral deposit signatures by borehole geophysics: data from the borehole geophysical test site at the McConnell nickel deposit (Garson Offset), Ontario

Cited by 6 publications

References 0 publications

Combined 3‐D Interpretation of Airborne, Surface, and Borehole Vector Magnetics at the McConnell Nickel Deposit

Combined 3‐D Interpretation of Airborne, Surface, and Borehole Vector Magnetics at the McConnell Nickel Deposit

Combined 3‐D interpretation of airborne, surface, and borehole vector magnetics at the McConnell Nickel deposit

Radio tomography and borehole radar delineation of the McConnell nickel sulfide deposit, Sudbury, Ontario, Canada

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