Over the last 15 years or so, there has been significant innovation in integrated exploration targeting to support how and where mining companies are to search for new deposits. Exploration is increasingly focused on targets at depth or under cover where the remote sensing role of geophysics takes on a new role in the exploration process. Strategies relying on the identification of geophysical anomalies are giving way to the integrated characterization and identification of mineralized systems footprint(s), helping vector towards ore. Integrated exploration targeting is the process by which exploration geoscientists merge, quantify and weigh the contribution of geology, geophysics, and geochemistry to produce a coherent 3D earth model to support mineral exploration decisions, from survey planning to drillhole targeting. This approach relies on, but also forces key technological innovations in data management, quantitatively-integrated geological and geophysical modelling, and pattern recognition through machine learning. We describe four instrumental advances in integrated exploration targeting: 1) the ore system footprint versus anomaly paradigm; 2) the use of geophysical data in the interpretation of alteration; 3) machine learning to reveal subtle relationships amongst data that are diagnostic of ore forming processes and their footprint; and 4) data acquisition simulations to optimize exploration strategy and plan data acquisition.

A generalized interpolation framework using radial basis functions (RBF) is presented that implicitly models three-dimensional continuous geological surfaces from scattered multivariate structural data. Generalized interpolants can use multiple types of independent geological constraints by deriving for each, linearly independent functionals. This framework does not suffer from the limitations of previous RBF approaches developed for geological surface modelling that requires additional offset points to ensure uniqueness of the interpolant. A particularly useful application of generalized interpolants is that they allow augmenting on-contact constraints with gradient constraints as defined by strike-dip data with assigned polarity. This interpolation problem yields a linear system that is analogous in form to the previously developed potential field implicit interpolation method based on co-kriging of contact increments using parametric isotropic covariance functions. The general form of the mathematical framework presented herein allows us to further expand on solutions by: (1) including stratigraphic data from above and below the target surface as inequality constraints (2) modelling anisotropy by data-driven eigen analysis of gradient constraints and (3) incorporating additional constraints by adding linear functionals to the system, such as fold axis constraints. Case studies are presented that demonstrate the advantages and general performance of the surface modelling method in sparse data environments where the contacts that constrain geological surfaces are rarely exposed but structural and off-contact stratigraphic data can be plentiful.

3D modelling in hard rock settings is challenging due to post-ore tectono-metamorphic processes and the structural complexity and heterogeneity of ore-hosting crystalline basement rocks. This paper discusses avenues towards confronting the challenges from the perspective of optimally using geologic constraints.

The Downhole Seismic Imaging consortium conducted two consecutive vertical seismic profiling surveys in the Norman West mining camp (Sudbury, Canada) in 1998 and 1999. These were aimed toward imaging a massive sulfide ore deposit situated within the footwall of the Sudbury Igneous Complex (SIC). Three-component seismic data were acquired in four boreholes with variable signal-to-noise ratio and poor polarization quality. Consequently, the images suffered from strong azimuthal ambiguity. A strike filter, passing only reflections originating from within the SIC, was applied during migration to enhance interpretability of the images obtained. Migrated images showed structures correlating with the known position of an ore deposit located 1800 m away from one borehole (N40). Diffraction coherency migration enhanced the image of the deposit, and suggested strong seismic scattering from within the footwall of the SIC.

Software technology is developing rapidly, changing the way we can utilise geoscience datasets. A major change has been the advent of new quantitative structural modelling in place of traditional sectional interpretations. Technology now offers the ability to host numerous datasets and facilitates easy integration for analysis, research and understanding relationships between multi-disciplinary data.

ABSTRACT Exploration for deep-seated mineral deposits in mature mining camps requires integration of large and heterogeneous spatial data-sets. Traditionally, geological, geochemical, and geophysical observations are acquired, processed and analysed independently within separate spatial contexts or more commonly, for geochemical data, in non-spatial feature space. Although methodological developments are still in progress, 3D GIS (geographic information system) technologies already provide powerful tools that can be used to integrate such heterogeneous data-sets to visualize, compare, and characterize geological relationships in a more supportive interpretive environment. Importantly, this technology provides better opportunities to embed all these properties in a more robust geometric framework in which structural history and palaeogeographic setting can be taken into account. We present 3D GIS applications that aid in interpreting relationship patterns amongst faults, folds and geochemical trends. Examples from the Noranda mining region, a classic VMS mining camp, demonstrate the applicability of 3D GIS to support the discovery of new mineral resources at depth.

Exploration technologies now facilitate integration of multi-disciplinary datasets in 3D. Examples being geology and structural models, physical rock properties from inverted geophysical data and geochemical alteration indices. To integrate these data for quantification processes, assessment and visualisation the Common Earth Model concept has been devised. Using this in collaboration with a software workflow, the expert process of 3D Mineral Potential Modeling has been captured and made accessible to exploration practitioners. The workflow ensures rigorous and repeatable application of knowledge-driven and data-driven approaches to Mineral Potential Modeling. The Mineral Potential Targeting workflow is demonstrated with the Ribago District VHMS case study. Five evidential properties are utilised with the Multi-class index overlay knowledge-driven approach, generating over ten clearly defined and ranked 3D target volumes. Individual cells within these volumes are selected as drill targets. The workflow provides increased productivity and repeatability for any targeting exercise, and converts an expert system into an easy to use software application.

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2008The role of 3D earth models in seismic reflection methods applied to mineral explorationAuthors: Gervais PerronCalin CosmaGervais PerronMira Geoscience Ltd., 310 Victoria Ave, Suite 309, Westmount, QC, H3Z 2M9 CanadaSearch for more papers by this author and Calin CosmaVibrometric Canada, 366 Adelaide St E, Suite 425, Toronto, ON, M5A 3X9, CanadaSearch for more papers by this authorhttps://doi.org/10.1190/1.3064085 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Over the past five years, the use of seismic reflection methods for mineral exploration has increased significantly. Although, the overall industry knowledge is still based on very few surveys and each new survey can be considered unique. There is no pre‐established quick recipe when it comes to using seismic reflection methods in the search for the next generation of deep ore bodies. The complexity of the geological settings hosting mineralization can be high making the usage of 3D earth models for the purpose of survey design and data interpretation mandatory. The 3D earth model is at the core of a proposed stepwise approach for applying seismic reflection methods for mineral exploration. Such an approach has been successfully used by Kennecott Minerals for nickel sulphide exploration at the Eagle deposit in Michigan, USA. A 3D earth model attributed with physical rock properties was used for survey design optimization, advanced processing techniques and data interpretation. Integration and 3D visualization of complex seismic results with conventional exploration data sets lead to a better understanding of the contribution of seismic reflection methods for deep mineral exploration programs.Permalink: https://doi.org/10.1190/1.3064085FiguresReferencesRelatedDetails SEG Technical Program Expanded Abstracts 2008ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2008 Pages: 3713 publication data© 2008 Copyright © 2008 Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished: 15 Dec 2008 CITATION INFORMATION Gervais Perron and Calin Cosma, (2008), "The role of 3D earth models in seismic reflection methods applied to mineral exploration," SEG Technical Program Expanded Abstracts : 3629-3631. https://doi.org/10.1190/1.3064085 Plain-Language Summary PDF DownloadLoading ...

A query framework for spatial targeting within a 3-D geographic information system (GIS) software environment is introduced. Input to a query consists of parameters relevant to the query type together with a set of Common Earth Modelling objects represented as point sets, polygonal lines, surfaces, and grids or a region set (subset) thereof. The result of a 3-D GIS query is a region within each of the input objects that consists of nodes or grid cells where the query criteria was satisfied. We provide example scenarios, drawn from mineral exploration, where 3-D queries are used to guide spatial targeting within a near-mine or regional map scale setting. Query types supported are: proximity query (to a “probe” object), property query (numeric attribute), shell query (containment within a closed surface), meta-data query, feature query (dome, depression, curvature), trend query (dip plane, vector) and intersection query (with a “probe” object). Queries can be specific for a given object type but in general transcend object types. Standard set theoretical operations for a query results in newly defined regions and are supported within the Gocad© development environment. This development focuses on queries relevant in the 3-D data integration and interpretation stages of mature geological model development as well as early analysis, typically undertaken before a fully partitioned and attributed 3-D topological model is available.

Downhole seismic data were acquired at the Victor kimberlite, in the James Bay Lowlands of Ontario, in order to attempt to produce an image of the pipe at 10 to 300mdepths and, in doing so, to evaluate the applicability of this method in delineating diamond resources. The survey was designed to allow two different imaging strategies, one using shot points located over the kimberlite pipe and the other using shots over the host sedimentary rocks. It was hoped that shot points over the kimberlite would directly image the kimberlite-sedimentary rock contact, whereas shots over the nearby (<250 m) sedimentary rocks would indirectly determine the kimberlite margin by mapping truncations of reflections from the sedimentary layers. Results demonstrate that the indirect mapping approach has potential to define the geometry of the kimberlite at depth.

PreviousNext No AccessHardrock Seismic Exploration13. Application of Downhole Seismic Imaging to Map Near-Vertical Structures: Normétal (Abitibi Greenstone Belt), QuébecAuthors: G. PerronD. W. EatonB. ElliotD. SchmittG. Perron, D. W. Eaton, B. Elliot, and D. Schmitthttps://doi.org/10.1190/1.9781560802396.ch13 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract The downhole seismic imaging (DSI) technique is a recently developed approach for imaging the subsurface in the vicinity of an exploration borehole. The method combines multioffset, multiazimuth vertical seismic profiling (VSP) data acquisition with various 3D seismic imaging techniques, and is particularly well suited to structural settings in which features of interest (e.g., shear zones, lithological contacts) are subvertical. This is a typical characteristic of large parts of the Abitibi greenstone belt, the world's largest and most productive Archean granite-greenstone terrane. As an illustration of this technique, we apply the DSI approach to map the subsurface around a borehole near the (abandoned) Normétal Zn-Cu mine in northwestern Québec. The results of this study illustrate the capability of the DSI method for imaging steeply dipping volcanic units over distances of >500 m, and for detecting out-of-plane high-impedance bodies. In this case, these high-impedance bodies are Archean diabase dikes. Permalink: https://doi.org/10.1190/1.9781560802396.ch13FiguresReferencesRelatedDetailsCited byHydrophone VSP surveys in hard rockAndrew Greenwood, Christian J. Dupuis, Milovan Urosevic, and Anton Kepic6 September 2012 | GEOPHYSICS, Vol. 77, No. 5Seismic methods in mineral exploration and mine planning: A general overview of past and present case histories and a look into the futureAlireza Malehmir, Raymond Durrheim, Gilles Bellefleur, Milovan Urosevic, Christopher Juhlin, Donald John White, Bernd Milkereit, and Geoff Campbell7 September 2012 | GEOPHYSICS, Vol. 77, No. 5Elastic seismic wave scattering and imaging of massive sulfides: rock physics and implications for seismic data acquisition and processingE. L. Bongajum, I. White, and B. Milkereit21 October 2010 Hardrock Seismic ExplorationISBN (print):978-1-56080-114-6ISBN (online):978-1-56080-239-6Copyright: 2003 Pages: 277 publication data© 2003 All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means without written permission of the publisherPublisher:Society of Exploration Geophysicists HistoryPublished in print: 01 Jan 2003 CITATION INFORMATION G. Perron, D. W. Eaton, B. Elliot, and D. Schmitt, (2003), "13. Application of Downhole Seismic Imaging to Map Near-Vertical Structures: Normétal (Abitibi Greenstone Belt), Québec," Geophysical Developments Series : 194-206. https://doi.org/10.1190/1.9781560802396.ch13 Plain-Language Summary PDF DownloadLoading ...

PreviousNext No AccessHardrock Seismic Exploration15. 3D Seismic Imaging for VMS Deposit Exploration, Matagami, QuebecAuthors: Erick AdamGervais PerronGrant ArnoldLarry MatthewsBernd MilkereitErick Adam, Gervais Perron, Grant Arnold, Larry Matthews, and Bernd Milkereithttps://doi.org/10.1190/1.9781560802396.ch15 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Detecting deep mineral resources in the vicinity of existing mining camps is expensive and time consuming. The 3D seismic method is used routinely in oil and gas exploration to map deep stratigraphic contacts and structural features. Its ability to map volcanic contacts and the 1-km deep Bell Allard volcanogenic massive sulfide (VMS) deposit was tested recently in the Matagami mining camp. The survey objectives were to identify the seismic response of a VMS ore deposit and to map the main lithological contacts. The Bell Allard VMS deposit appears as a 100 m wide zone of high seismic amplitudes. The deposit is underlain by a larger amplitude anomaly that we attribute to a gabbro sill, or possibly to the alteration zone of the deposit. We show that the depth of the main exploration target (the Key Tuffite) can be identified on a large portion of the seismic survey area and that its southwest limit defines the location of a regional fault (the Daniel fault). The azimuth and dip of a synvolcanic fault was determined from amplitude analysis of a large gabbro sill. The Matagami 3D seismic experiment shows that seismic methods can image a deep VMS deposit and map important lithological contacts at a regional scale at a cost comparable to two 800-m deep boreholes per square kilometer. When applied in the appropriate geological context, a 3D seismic survey has the potential to assist deep mineral exploration and increase the chances of making cost-effective discoveries. Permalink: https://doi.org/10.1190/1.9781560802396.ch15FiguresReferencesRelatedDetailsCited bySeismic imaging across fault systems in the Abitibi greenstone belt – an analysis of pre- and post-stack migration approaches in the Chibougamau area, Quebec, Canada19 May 2021 | Solid Earth, Vol. 12, No. 5Sparse 3D reflection seismic survey for deep-targeting iron oxide deposits and their host rocks, Ludvika Mines, Sweden24 February 2021 | Solid Earth, Vol. 12, No. 2High‐resolution seismic imaging of crooked two‐dimensional profiles in greenstone belts of the Canadian shield: results from the Swayze area, Ontario, Canada9 August 2019 | Geophysical Prospecting, Vol. 68, No. 1Diffractivity — Another attribute for the interpretation of seismic data in hard rock environment, a case studyMohammad Javad Khoshnavaz, Andrej Bóna, Muhammad Shahadat Hossain, Milovan Urosevic, and Kit Chambers5 August 2016 | Interpretation, Vol. 4, No. 4Using supervirtual first arrivals in controlled-source hardrock seismic imaging—well worth the effort29 April 2016 | Geophysical Journal International, Vol. 206, No. 1Enhancing 3D post-stack seismic data acquired in hardrock environment using 2D curvelet transform13 March 2015 | Geophysical Prospecting, Vol. 63, No. 4Delineating structures controlling sandstone-hosted base-metal deposits using high-resolution multicomponent seismic and radio-magnetotelluric methods: a case study from Northern Sweden6 April 2015 | Geophysical Prospecting, Vol. 63, No. 43D seismic survey for geothermal exploration in crystalline rocks in Saxony, Germany23 April 2015 | Geophysical Prospecting, Vol. 63, No. 4High-resolution 2D seismic imaging and forward modeling of a polymetallic sulfide deposit at Garpenberg, central SwedenOmid Ahmadi, Christopher Juhlin, Alireza Malehmir, and Mie Munck8 October 2013 | GEOPHYSICS, Vol. 78, No. 63D stochastic gravity inversion using nonstationary covariancesPejman Shamsipour, Denis Marcotte, Michel Chouteau, Martine Rivest, and Abderrezak Bouchedda1 February 2013 | GEOPHYSICS, Vol. 78, No. 2Multidisciplinary study of the hanging wall of the Kiirunavaara iron ore deposit, northern SwedenMai-Britt Jensen, Artem Kashubin, Christopher Juhlin, and Sten-Åke Elming12 October 2012 | GEOPHYSICS, Vol. 77, No. 63D constraints and finite-difference modeling of massive sulfide deposits: The Kristineberg seismic lines revisited, northern SwedenMahdieh Dehghannejad, Alireza Malehmir, Christopher Juhlin, and Pietari Skyttä6 September 2012 | GEOPHYSICS, Vol. 77, No. 53D reflection seismic imaging for open-pit mine planning and deep exploration in the Kevitsa Ni-Cu-PGE deposit, northern FinlandAlireza Malehmir, Christopher Juhlin, Chris Wijns, Milovan Urosevic, Petri Valasti, and Emilia Koivisto7 September 2012 | GEOPHYSICS, Vol. 77, No. 53D imaging challenges in steeply dipping mining structures: New lights on acquisition geometry and processing from the Brunswick no. 6 seismic data, CanadaSaeid Cheraghi, Alireza Malehmir, and Gilles Bellefleur6 September 2012 | GEOPHYSICS, Vol. 77, No. 53D seismic imaging of volcanogenic massive sulfide deposits in the Flin Flon mining camp, Canada: Part 1 — Seismic resultsD. J. White, D. Secord, and M. Malinowski6 September 2012 | GEOPHYSICS, Vol. 77, No. 52D reflection seismic investigations at the Kevitsa Ni-Cu-PGE deposit, northern FinlandEmilia Koivisto, Alireza Malehmir, Pekka Heikkinen, Suvi Heinonen, and Ilmo Kukkonen7 September 2012 | GEOPHYSICS, Vol. 77, No. 5Seismic methods in mineral exploration and mine planning: A general overview of past and present case histories and a look into the futureAlireza Malehmir, Raymond Durrheim, Gilles Bellefleur, Milovan Urosevic, Christopher Juhlin, Donald John White, Bernd Milkereit, and Geoff Campbell7 September 2012 | GEOPHYSICS, Vol. 77, No. 5Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits30 November 2011 | Journal of Geophysical Research: Solid Earth, Vol. 116, No. B113D reflection seismic investigation for mine planning and exploration in the Kevitsa Ni‐Cu‐PGE deposit, northern FinlandAlireza Malehmir, Christopher Juhlin, Chris Wijns, Milovan Urosevic, Petri Valasti, Emilia koivisto, Ilmo Kukkonen, Pekka Heikkinen, and Markku Paananen25 May 2012Enhancing base-metal exploration with seismic imagingThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe — parameters, processes, and the evolution of a continent .Canadian Journal of Earth Sciences, Vol. 47, No. 5Elastic seismic wave scattering and imaging of massive sulfides: rock physics and implications for seismic data acquisition and processingE. L. Bongajum, I. White, and B. Milkereit21 October 20103D seismic reflection imaging of volcanic-hosted massive sulfide deposits: Insights from reprocessing Halfmile Lake data, New Brunswick, CanadaAlireza Malehmir and Gilles Bellefleur4 December 2009 | GEOPHYSICS, Vol. 74, No. 6Shallow 3D seismic-reflection imaging of fracture zones in crystalline rockCedric Schmelzbach, Heinrich Horstmeyer, and Christopher Juhlin31 October 2007 | GEOPHYSICS, Vol. 72, No. 6Physical property analysis, numerical and scale modeling for planning of seismic surveys: Voisey's Bay, LabradorDeanne Duff and C. A. Hurich6 October 2006 Hardrock Seismic ExplorationISBN (print):978-1-56080-114-6ISBN (online):978-1-56080-239-6Copyright: 2003 Pages: 277 publication data© 2003 All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means without written permission of the publisherPublisher:Society of Exploration Geophysicists HistoryPublished in print: 01 Jan 2003 CITATION INFORMATION Erick Adam, Gervais Perron, Grant Arnold, Larry Matthews, and Bernd Milkereit, (2003), "15. 3D Seismic Imaging for VMS Deposit Exploration, Matagami, Quebec," Geophysical Developments Series : 229-246. https://doi.org/10.1190/1.9781560802396.ch15 Plain-Language Summary PDF DownloadLoading ...

New vertical seismic profiles from the northwest margin of the Sudbury impact structure provide details of structural geometries within the lower impact melt sheet (usually called the Sudbury Igneous Complex) and the sublayer norite layer. Vertical seismic profile sections and common depth point transformation images display several continuous reflections that correlate with faults and stratigraphic boundaries logged from drill cores. Of four possible mechanisms that explain repeated rock units, late-stage flow or normal faulting that occurred within the last layers to cool and crystallize might best explain the observations, especially the most prominent reflectors observed in the seismic data. These results reaffirm previously proposed two-stage cooling and deformation models for the impact melt sheet.

DSISoft is a public domain vertical seismic profile processing software package developed at the Geological Survey of Canada. DSISoft runs under MATLAB version 5.0 and above and hence is portable between computer operating systems supported by MATLAB (i.e. Unix, Windows, Macintosh, Linux). The package includes processing modules for reading and writing various standard seismic data formats, performing data editing, sorting, filtering, and other basic processing modules. The processing sequence can be scripted allowing batch processing and easy documentation. A structured format has been developed to ensure future additions to the package are compatible with existing modules. Interactive modules have been created using MATLAB's graphical user interface builder for displaying seismic data, picking first break times, examining frequency spectra, doing f–k filtering, and plotting the trace header information. DSISoft modular design facilitates the incorporation of new processing algorithms as they are developed. This paper gives an overview of the scope of the software and serves as a guide for the addition of new modules.

M-15 3-D IMAGING OF CRUSTAL LITHOLOGY WITH DIFFRACTION COHERENCY MIGRATION FOR VSP CF. MUELLER 1 G. BELLFLEUR 1 G. PERRON 4 K. STEVENS 2 D. SNYDER 1 and B. MILKEREIT 3 Summary 1 Diffraction coherency migration (DCM) was applied to a multi-offset multi-azimuth vertical seismic profiling survey conducted in the northeastern part of the Sudbury impact structure in Ontario Canada. Seismic data was collected by the downhole seismic imaging (DSI) consortium with a three component geophone array in two boreholes using five shot points at the surface. Based on diffraction stack migration DCM was developed to enhance the subsurface image