Scaling behavior and the effects of heterogeneity on shallow seismic imaging of mineral deposits: A case study from Brunswick No. 6 mining area, Canada

Cheraghi, Saeid; Malehmir, Alireza; Bellefleur, Gilles; Bongajum, Emmanuel; Bastani, Mehrdad

doi:10.1016/j.jappgeo.2012.12.003

Cited by 21 publications

(15 citation statements)

References 63 publications

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“…Several authors have reported positive results from around the world (e.g., Bellefleur, Malehmir, and Müller C. ; Ehsan, Malehmir, and Dehghannejad ; White, Secord, and Malinowski ; Cheraghi, Malehmir, and Bellefleur ; Cheraghi et al . ; Dehghannejad et al . , ; Malinowski, Schetselaar, and White ; Ahmadi et al .…”

Section: Introductionmentioning

confidence: 99%

Building a 3D model of lithological contacts and near‐mine structures in the Kevitsa mining and exploration site, Northern Finland: constraints from 2D and 3D reflection seismic data

Koivisto

Malehmir

Hellqvist

et al. 2015

Geophysical Prospecting

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A B S T R A C TThe Kevitsa mafic-ultramafic intrusion in Northern Finland hosts a large, disseminated nickel-copper sulphide ore body. The Kevitsa intrusion is an active mining and exploration site, for which we have built a 3D model of the main lithological contacts and near-mine structures in the area. To build the 3D model, 2D and 3D reflection seismic data have been used together with borehole data and geological map of the area. The Kevitsa reflection seismic data reveal the internal architecture of the Kevitsa intrusion and the surrounding units. For example, the seismic data have uncovered a previously unknown, deeper continuation of the Kevitsa intrusion. Improved 3D knowledge of the basal contact of the intrusion provides an exploration target for contact-type mineralization. Within the intrusion, a limited area of strong reflections is observed in the data. This has been associated with discontinuous, smaller-scale magmatic layering that is thought to control the extent of the Kevitsa main mineralization. Thus, our 3D model of the extents of the internal reflectors can provide a framework for near-mine and deep exploration of the main type of mineralization in the area. In addition to exploration, the original purpose of the 3D seismic survey was geotechnical planning of the Kevitsa open-pit mine. Accordingly, the 3D seismic data were used to create a 3D model of the subsurface structures, with a focus on the vicinity of the mine. The interpreted structures reveal a complex pattern of fault and fracture zones, some of which will be important for slope stability and operational planning of the final stages of the mine.

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Section: Introductionmentioning

confidence: 99%

Building a 3D model of lithological contacts and near‐mine structures in the Kevitsa mining and exploration site, Northern Finland: constraints from 2D and 3D reflection seismic data

Koivisto

Malehmir

Hellqvist

et al. 2015

Geophysical Prospecting

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“…The DMO stacked section of the north survey and CDMO analysis also provided insight into the diffractions within the upper crust. Diffractions could be generated from spherical/elliptical (ore) bodies within fault zone structures and thus potentially relevant to mineral exploration Cheraghi et al, 2013;Bellefleur et al, 2019). Our analysis suggests the utility of considering DMO stacked sections with cross-dips to image diffractions better.…”

Section: Seismic Interpretation Along the North Profilementioning

confidence: 89%

“…diffractions are easy to miss so that a focused visual inspection is necessary Cheraghi et al, 2013;).…”

Section: Seismic Interpretation Along the North Profilementioning

confidence: 99%

Seismic imaging across fault systems in the Abitibi greenstone belt – An analysis of pre- and post-stack migration approaches in the Chibougamau area, Quebec, Canada

Cheraghi¹,

Malehmir²,

Naghizadeh³

et al. 2020

Preprint

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Abstract. Two high-resolution seismic reflection profiles acquired north and south of Chibougamau, located in the northeast of the Abitibi subprovince of Canada help understand historic volcanic-hosted massive sulfide (VMS) deposits and hydrothermal Cu-Au mineralization found there. Major faults crossed by the profiles include the Barlow fault in the north and the Doda fault and the Guercheville fault in the south, all targets of this study that seeks to determine spatial relationships with known metal endowment in the area. Common-offset DMO corrections and common-offset pre-stack time migrations (PSTM) were considered. Irregularities of the trace midpoint distribution resulting from the crooked geometry of both profiles and their relative contribution to DMO and PSTM method and seismic illumination were assessed in the context of the complex subsurface architecture of the area. To scrutinize this contribution, seismic images were generated for offset ranges of 0–9 km using increments of 3 km. Migration of out-of-plane reflections used cross-dip element analysis to accurately estimate the fault dip. The seismic imaging shows the thickening of the upper crustal rocks near the fault zones along both profiles. In the north seismic reflection section, key geological structure identified include the Barlow fault and two diffraction sets imaged within the fault zone that represent potential targets for future exploration. The south seismic reflection section shows rather a complicated geometry of two fault systems. The Guercheville fault observed as a subhorizontal reflector connects to a steeply dipping reflector. The Doda fault dips subvertical in the shallow crust but as a steeply dipping reflection set at depth. Nearby gold showings suggest that these faults may help channel and concentrate mineralizing fluids.

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“…12b. This is not surprising as modelling work done by Cheraghi et al (2013) shows that diffractions and reflections generated from small bodies are in general more coherent in DMO stacked images than on migrated images where most of energy related to those diffractions and small bodies are collapsed at the apex of diffractions.…”

Section: Removing Dmo Processing Artefacts In Wavenumber Domainmentioning

confidence: 91%

Reprocessing legacy three-dimensional seismic data from the Halfmile Lake and Brunswick No. 6 volcanogenic massive sulphide deposits, New Brunswick, Canada

2019

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We reprocessed legacy three-dimensional (3D) seismic data from the Halfmile Lake and Brunswick areas, both of which were acquired for mineral exploration in the Bathurst Mining Camp, New Brunswick. Each 3D seismic survey was acquired over known volcanogenic massive sulphide deposits and covered areas with strong mineral potential. Most improvements resulted from a reduction of coherent and random noise on prestack gathers and from an improved velocity model, combined with re-imaging with dip moveout corrections and poststack migration or prestack time migration. At Halfmile Lake, the new imaging results show the Deep zone and a possible extension of the sulphide mineralization at greater depth. True amplitude processing has shown that this anomaly has strong amplitudes and is offset from the Deep zone by a shallowly dipping fault (<15°). With the clearer geological context provided by our results, this anomaly, which appears as a stand-alone anomaly on an original image obtained by Noranda Exploration Ltd., becomes a defendable exploration target. Nonorthogonal acquisition geometry and receiver patches of the Brunswick No. 6 3D seismic survey generated artefacts after dip moveout processing that reduced the overall quality of the seismic volumes. By using a filtering approach based on the application of a weighted Laplacian-Gaussian filter in the Kx–Ky domain, we reduced the noise and improved the continuity of reflections. We also imaged the short and flat reflections observed previously only in the shallow part of prestack time migrated data. These short reflections appear as diffractions on the filtered stacked section with dip moveout corrections, indicating that they originate from small geological bodies or discontinuities in the subsurface.

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Scaling behavior and the effects of heterogeneity on shallow seismic imaging of mineral deposits: A case study from Brunswick No. 6 mining area, Canada

Cited by 21 publications

References 63 publications

Building a 3D model of lithological contacts and near‐mine structures in the Kevitsa mining and exploration site, Northern Finland: constraints from 2D and 3D reflection seismic data

Building a 3D model of lithological contacts and near‐mine structures in the Kevitsa mining and exploration site, Northern Finland: constraints from 2D and 3D reflection seismic data

Seismic imaging across fault systems in the Abitibi greenstone belt – An analysis of pre- and post-stack migration approaches in the Chibougamau area, Quebec, Canada

Reprocessing legacy three-dimensional seismic data from the Halfmile Lake and Brunswick No. 6 volcanogenic massive sulphide deposits, New Brunswick, Canada

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