SummaryThe Borden Gold deposit (9.3 Mt @ 5.3 g/t Au) is a structurally controlled Archean mesothermal lode gold deposit within the Kapuskasing Structural Zone, in northern Ontario. Helicopter VTEM and magnetic surveys were flown over the Borden Gold deposit, helping to design the first drilling program, leading to the discovery in 2010. Initial survey results defined the extension of the near surface low-grade-zone (LGZ). Advanced processing and modelling of VTEM data also appears to map the deeper high-grade-zone (HGZ). Results of subsequent 1D imaging and 2.5D inversions, and airborne inductive induced polarization (AIP) analysis, are also presented.

In September 2015, a deep penetrating VTEM helicopter time-domain EM survey was used to explore the Rice Island Ni-Cu-Co property, located southeast of Snow Lake, Manitoba. In addition to highlighting Rice Island’s known flat-lying Main Zone Ni-Cu-Co deposit and several other favorable targets on the property with similar characteristics, the VTEM survey results also identified a subvertical conductive zone, open at depth, which represented a potential feeder zone. The subsequent 2015-2016 drill program in combination with Fixed-loop and borehole time-domain EM surveys, tested two new conductive targets proximal to the Main Zone (MZ) and encountered significant mineralization at depth, leading to the discovery of the “New Lower Zone” (NLZ). Modelling of the VTEM and Fixed-loop and borehole conductors associated with the MZ and NLZ suggests that mineralization persists to depth and also along strike. Presentation Date: Wednesday, September 27, 2017 Start Time: 4:45 PM Location: 360C Presentation Type: ORAL

Data acquired by airborne in-loop time-domain electromagnetic (EM) systems, such as VTEMTM (Witherly et al., 2004), reflect mainly three physical phenomena in the earth: (1) EM induction, related to ground conductivity, (2) Airborne Inductively Induced Polarization (AIIP), related to the relaxation of polarized charges in the ground (Kratzer & Macnae 2012, Kwan et al., 2015) and (3) Superparamagnetism (SPM), related to the induced secondary magnetic field of certain ultrafine to fine grained magnetic materials (Kratzer, Macnae & Mutton 2013, Sattel & Mutton 2015). It is also called magnetic relaxation or magnetic viscosity. Olhoeft and Strangway (1974) predicted that the SPM effect could become relatively more important and permit mapping of magnetite content with an active, more sophisticated EM system. However, as a background effect it could also represent an additional source of signal to further complicate EM exploration. In this abstract, the general characteristics of SPM anomalies occurring over barren rocks in Greenland, in an environment different from Australia and Southern Africa, are discussed and a method of identifying them in VTEM data will be presented. Presentation Date: Tuesday, October 18, 2016 Start Time: 3:45:00 PM Location: 168 Presentation Type: ORAL

Summary On January 19TH, 2012, Zenyatta Ventures Ltd. (Zenyatta) announced the discovery of a very rare type of hydrothermal graphite deposit on its Albany Project. The discovery was based on drill testing of anomalies identified by airborne electromagnetic survey flown in 2010 by Geotech Ltd. using its prototype VTEMMAX time-domain EM system. Crone Geophysics & Exploration Ltd. (Crone) was contracted by Zenyatta to perform surface time-domain EM (TDEM) surveys on the Property during February and March 2013. Crone targeted the drill-confirmed East and West graphitic breccia pipes using an in-loop and out-ofloop configuration to couple with their top and steeply dipping edges, respectively, and successfully outlined their lateral extents.

The 14.4-Mt Lalor copper-zinc-gold deposit situated in the Flin Flon Greenstone Belt of north-central Manitoba is large ([Formula: see text]) but deeply buried ([Formula: see text]) and was discovered using deep penetrating ground fixed-loop time-domain electromagnetic (EM). Results from three different airborne EM surveys over a five-year span permit comparisons of the system responses over the Lalor volcanogenic massive sulfide deposit region, assisted using 1D-2D-3D inversions. In late March, 2007, soon after its drilling discovery, Hudson Bay Exploration contracted Geotech to fly helicopter versatile time-domain electromagnetic (VTEM) surveys over the region west of Snow Lake, Manitoba. The deposit was not detected due to its large depth of burial ([Formula: see text]) and the lack of magnetic response. In 2009, Geotech carried out a helicopter z‐axis tipper electromagnetic (ZTEM) passive EM test survey over the Lalor deposit, which was successful and led to a larger survey over the area. In 2012, a second VTEM survey test was flown, using the more deeply penetrating [Formula: see text] system. Although it had sufficient penetration to detect the orebody, on-site mine-site development appeared to overprint the deeper [Formula: see text] deposit response. However, a deep ([Formula: see text]) conductive anomaly from a stringer sulfide occurrence, known as South Bull’s Eye, which lies south of Lalor, was well resolved in the ZTEM and [Formula: see text] surveys.

VTEM helicopter time-domain EM survey results over the Brandon Channel and Assiniboine Delta aquifers, near Brandon, Manitoba, have been studied using unconstrained layered earth modeling. The resistive sand and gravel layers are distinguished from the more conductive shale basement and reveal localized thickening from blind gravel channels cut into its floor. They further distinguish a lower aquifer separated by a conductive clay layer from shallow sands of the Assiniboine Alluvial aquifer and the Assiniboine Delta Aquifer. The Brandon Channel aquifer is delineated, to the northwest and east of the city where it splits into a main south channel and smaller north channel. The western extent of Assiniboine Alluvial aquifer is defined and evidence for the Pierson Valley aquifer extending west from Brandon is also indicated.

Summary VTEM helicopter time-domain EM survey results over the Brandon Channel and Assiniboine Delta aquifers, near Brandon, Manitoba, have been studied using unconstrained layered earth modeling. The resistive sand and gravel layers are distinguished from the more conductive shale basement and reveal localized thickening from blind gravel channels cut into its floor. They further distinguish a lower aquifer separated by a conductive clay layer from shallow sands of the Assiniboine Alluvial aquifer and the Assiniboine Delta Aquifer. The Brandon Channel is mapped, including a secondary channel further north. The western extent of Assiniboine Alluvial aquifer is defined and evidence for the Pierson Valleyaquifer extending west from Brandon is also indicated.

The individual abstracts for this session are available to read in the PDF.

Summary Airborne geophysical surveys, consisting of fixed-wing magnetic gradiometer and gamma-ray spectrometer and helicopter-borne full-waveform Versatile Time-Domain Electromagnetic (VTEM) surveys were carried out over the Iullemmeden basin, in western Niger for mineral exploration and detailed geological mapping. The eastern portion of the basin is known to include substantial phosphate, lignite coal and iron ore deposits whereas, the western portion, which belongs to the Liptako Metallogenic Province, hosts several mineral occurrences including base and precious metals, precious stones and special metals in various deposit styles. Geophysical data integration with other available types of information including Landsat ETM+ imagery and geological maps has been performed using innovative approaches based on Neural Networks (NN) and Enhanced Maximum Likelihood (EML) supervised classification techniques. Combined techniques have proven very useful during the analysis of multidisciplinary data resulting in better understanding of the distribution of mineralization and the results were used for targeting and selecting new favorable areas for the exploration of various mineralization styles within the study area. Results of gamma-ray spectrometer, aeromagnetic and Landsat TM data interpretation and their integration with known geology suggest the existence of three metallogenic provinces within this area. The first two provinces are associated with tertiary sediments of the Iullemmeden basin and include potential radioactive mineralizations (uranium and thorium). The third province is associated with intrusive and metavolcanic sedimentary formations of the Birimian Liptako basement outcropping partly along the east side of the Niger River and hosting various styles of polymetallic mineralization (Cu, Pb, Zn, Ag), precious metals (gold and diamonds), special metals (Sn, W, Ta, Bi, Li, Ti), iron ore, REE and Ni-PGE mineralization.

Helicopter AeroTEM, VTEM and ZTEM surveys were flown over the 501 zone in the McFauld’s Lake area, northern Ontario. The 501 zone is a relatively small VMS deposit that appears to respond well to all three active and passive airborne EM systems that have surveyed the property. Comparisons between these data sets and the geology are showcased using 1D-2D-3D EM inversion modeling.

Heliborne VTEM and ZTEM surveys were flown over the Mayville property in south-east Manitoba. The VTEM results show good correlation with the Mayville Cu-Ni deposit and identify new areas for follow-up. ZTEM results correlate well with known geology, giving into the discovery of a PGM occurrence located one km to the southeast. Comparisons between these data sets and its geology are showcased using 1D-2D inversion modeling.

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2011ZTEM and VTEM airborne EM survey results over PGM‐Cu‐Ni targets at East Bull Lake anorthositic complex, Massey, OntarioAuthors: Jean M. LegaultMarta OrtaHarish KumarShengkai ZhaoJean M. LegaultGeotech Ltd.Search for more papers by this author, Marta OrtaGeotech Ltd.Search for more papers by this author, Harish KumarGeotech Ltd.Search for more papers by this author, and Shengkai ZhaoGeotech Ltd.Search for more papers by this authorhttps://doi.org/10.1190/1.3628158 SectionsSupplemental MaterialAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Heliborne VTEM and ZTEM surveys were flown over East Bull Lake Intrusive Complex near Massey ON. The VTEM results show good correlation with known occurrences and identify new areas for follow‐up. The ZTEM survey results correlate well with known geology and provide indications of deep structure that agree with previous scalar and tensor AMT survey results. Comparisons between these data sets and the East Bull Lake geology and structure are showcased using 1D‐2D‐3D inversion modeling.Permalink: https://doi.org/10.1190/1.3628158FiguresReferencesRelatedDetailsCited ByZTEM and VTEM airborne EM survey results over the Mayville Cu-Ni-PGM intrusive system, southeastern Manitoba.Marta Orta, Jean M. Legault, Shengkai Zhao, Carlos Izarra, Timothy Eadie, and Carey Galeschuk25 October 2012 SEG Technical Program Expanded Abstracts 2011ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2011 Pages: 4424 Publisher:Society of Exploration Geophysicists HistoryPublished: 25 May 2012 CITATION INFORMATION Jean M. Legault, Marta Orta, Harish Kumar, and Shengkai Zhao, (2011), "ZTEM and VTEM airborne EM survey results over PGM‐Cu‐Ni targets at East Bull Lake anorthositic complex, Massey, Ontario," SEG Technical Program Expanded Abstracts : 629-634. https://doi.org/10.1190/1.3628158 Plain-Language Summary PDF DownloadLoading ...

Summary A ZTEM (Z-Tipper Axis Electromagnetic) airborne AFMAG survey was conducted over the Reese River Test Block, situated in central Nevada in August, 2009. The Reese River prospect is a “blind” geothermal resource that lacks surface characteristics such as hot springs. A number of geophysical surveys have been conducted at the prospect, including seismic, gravity, magnetotelluric (MT) and radiometric surveys. Resistivity methods, such as MT, are typically used to map structure, lithology and alteration, particularly the smectite-zeolite zones which form a low resistivity cap over the outer margins of the higher resistive reservoir at depth. The ZTEM survey at Reese River has overflown lines previously surveyed using MT for comparison purposes. The ZTEM results appear to correlate very well with previous magnetotelluric results and the known geology, in particular the presence of both major and secondary fault structures and geologic contacts. 2D inversions of the airborne ZTEM appear to agree very well with the inversions obtained from ground MT, except in areas of pronounced 3D behaviour, where the 2D assumption is no longer valid.