Posts Tagged Geotech Ltd.

GEOMODEL – online time-domain EM data inversion

Posted by on Tuesday, 19 May, 2015
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Significant improvements have been made since the last presentation of the webapp on ExplorationGeophysics.Info pages. Now the shareware TDEM data inversion web application (ww.geomodel.info) has easy and comfy Eng-Rus interface, the input supports six different file formats (airborne and ground systems), sounding stations position can be represented on the scalable Google Map, data is showed in a sheet, TEM off-time decay chart and calculated apparent resistivity with time or depth.

AppResChart

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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The software can be used with data from WalkTEM, TerraTEM, ProTEM, Geotech airborne VTEM, TEM-FAST 48HPC, Tsikl and other TEM systems. A user can suggest any new data format and provide GEOMODEL developers with corresponded information.

The inversion process is interactive (forward modeling with thickness and/or resistivity changing) or iterative (automatic iterations to get correspondence between calculated and measured decay curve).

The inversion is based on 1D algorithm with support of CSIRO Division of Exploration and Mining and Australian Mineral Institute Research Association (AMIRA), P223F project.

Inversions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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The next procedures can be done with TDEM Geomodel webapp:

-Import-export TEM data and inversions from a large number of industrial formats, including USF;

-Viewing and analysis of transient field decay curves;

-Editing individual decays or tens of decays together in a fast and easy way;

-Runing 1D inversion and compiling resistivity sections;

-Saving results in ASCII format for further processing and presentation in third-party software (Surfer, Autocad, Geosoft Oasis Montaj, etc.).

-Saving inversion results as resistivity sections and maps in different image file formats.

The next example shows  Geotech airborne VTEM  data inversion (Alberta, Canada):

 

The development team welcomes user’s comments and suggestions.


EM surveys over Green Giant graphite property in Madagascar

Posted by on Tuesday, 24 February, 2015

by Alexander Prikhodko, 24 Feb., 2015

Graphite mineralization has a high electrical conductivity, which makes it an excellent target for electromagnetic (EM) methods.

Energizer Resources Inc. and it’s predecessors have conducted several airborne and ground electromagnetic  surveys over different areas of Green Giant graphite property in Madagascar (province of Toliara). Different EM technologies have been used in accordance with their progress.

Geological position and characteristics of the property:

Regional position – Ampanihy Shear Zone, NS foliation of rocks;

-Vertical to sub-vertical nature;

-The area is underlain by supracrustal and plutonic rocks deformed with N-NE trending structures;

-Graphitic zones consist of multi-folded graphitic strata;

-Graphitic schist and gneiss with vanadium mineralization.

 Geologic map (magnetic field interpretation)

Green_Giant_quick_Mag

 

AEM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AEM surveys covering with different technologies is in the picture above.

The basic AEM surveys results which demonstrate a potential of the territory and effectiveness of the applied methods are below.

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DIGHEM survey

Inverted (EMflow, Encom) DIGHEM data. Conductivity 3D voxel, sections and a map.

(conductors in red, resistors blue colors)

DIGHEMConVoxel

 

 

 

 

 

 

 

 

 

 

 

 

 

sections

 

condmap

 

 

 

 

 

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VTEM survey

Time-domain EM TAU parameter calculated with sliding window algorithm picks up the most conductive part of the geoelectrical section on each station-sounding.

TAU

 

 

 

 

 

 

 

 

 

 

 

 

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The resistivity-depth imaging (RDI) of EM time-domain data is a base of depth positioning of conductors potential for graphite mineralization and the first approximation of their geometry and dimensions.

rdisections

 

 

 

 

 

 

 

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3D apparent resistivity distribution with <1 Ohm-m clipping areas:

RDIvoxel

 


2014 issued patents by Assignee Geotech Airborne Limited

Posted by on Tuesday, 27 January, 2015
Patent number: 8878538
Abstract: An airborne geophysical surveying system comprising a receiver coil assembly for towing by an aircraft, the receiver assembly including a receiver coil for sensing changes in a magnetic field component of a magnetic field, and a receiver coil orientation sensing system for sensing orientation changes of the receiver coil. A controller receives signals representing the sensed changes in the magnetic field component from the receiver coil and the sensed orientation changes from the receiver coil orientation sensing system and corrects the sensed changes in the magnetic field component to provide a signal that is corrected for noise caused by changing orientation of the receiver coil in a static geomagnetic field.
Filed: November 26, 2010
Issued: November 4, 2014

Bucking coil and B-field measurement system and apparatus for time domain electromagnetic measurements

Patent number: 8786286
Abstract: According to one example embodiment is a time domain electromagnetic (TDEM) geophysical survey system for producing a B-field measurement, comprising: a transmitter coil; a bucking coil positioned in a substantially concentric and coplanar orientation relative to the transmitter coil; a receiver coil positioned in a substantially concentric and coplanar orientation relative to the bucking coil; an electrical current source connected to the transmitter coil and bucking coil for applying a periodic current thereto; and a data collection system configured to receive a magnetic field time-derivative signal dB/dt from the receiver coil and integrate the magnetic field time-derivative signal dB/dt to generate, a magnetic B-field measurement, the transmitter coil, bucking coil and receiver coil being positioned relative to each other such that, at the location of the receiver coil, a magnetic field generated by the bucking coil has a cancelling effect on a primary magnetic field generated by the transmitter coil.
Filed: August 28, 2009
Issued: July 22, 2014

Airborne time domain electromagnetic transmitter coil system and appratus

Patent number: 8766640
Abstract: A tow assembly for an airborne electromagnetic surveying system, including: a transmitter coil frame supporting a transmitter coil, the transmitter coil frame being formed from a plurality of serially connected frame sections forming a loop, the transmitter coil frame having rotating joints at a plurality of locations about a circumference thereof enabling the transmitter coil frame to at least partially bend at the rotating joints; and a suspension assembly for towing the transmitter coil frame behind an aircraft, the suspension assembly being attached to the circumference of the transmitter coil frame at spaced apart locations.
Filed: May 23, 2011
Issued: July 1, 2014

Airborne electromagnetic transmitter coil system

Patent number: 8674701
Abstract: A tow assembly for an airborne electromagnetic surveying system including a semi-rigid transmitter coil frame supporting a transmitter coil, the transmitter coil frame being formed from a plurality of serially connected frame sections forming a loop, the transmitter coil frame having articulating joints at a plurality of locations about a circumference thereof enabling the transmitter coil frame to at least partially bend at the articulating joints; and a suspension assembly for towing the transmitter coil frame behind an aircraft, the suspension assembly comprising a plurality of ropes and attached to the circumference of the transmitter coil frame at spaced apart locations.
Filed: February 25, 2009
Issued: March 18, 2014

Geology For Investors about an airborne EM technology for exploration

Posted by on Monday, 1 December, 2014

Hunting for Giants: An Introduction to ZTEM Surveys in Mineral Exploration
By: Kylie Williams in Exploration Methods

ZTEM

 

 

 

 

 

 

 

 

Overview

It may just look like an enormous, flying spider web towed behind a helicopter, but the ZTEM airborne geophysical survey system has the potential to identify giant porphyry copper deposits and features of other large ore deposits up to 2000 meters below the surface.
Z‐Tipper Axis Electromagnetic (ZTEM) is an airborne electromagnetic survey system which detects anomalies in the earth’s natural magnetic field. These disruptions are caused by zones of rock that conduct or resist electrical current more than the surrounding rock, like ore deposits. The proprietary technology belongs to Canadian company, Geotech, who have flown over 250,000 line-kilometres with ZTEM in under 4 years.

History

Geotech Ltd. is a Canadian airborne geophysical survey company that began operations in 1982. The company developed the now well-known VTEM (the versatile time-domain electromagnetic) system in 2002.
The helicopter version of the airborne Z‐Tipper Axis Electromagnetic (ZTEM) system was introduced into commercial service by Geotech in 2006-2007, and the less-expensive fixed-wing (FW ZTEM) system was introduced in 2010-11.

How ZTEM works

ZTEM specifications 300×225 Hunting for Giants: An Introduction to ZTEM Surveys in Mineral Exploration exploration methods ZTEM vtem uranium kimberlite exploration Geotech electromagnetism copper porphyry airborne geophysics
Flying spider web: the airborne loop of the ZTEM system (Geotech)
ZTEM is a type of electromagnetic (EM) survey to measure variations in the electrical properties of rocks.
EM surveys try to identify bodies of rock that conduct electricity well, like massive sulfide bodies of copper or nickel ore, or rocks that resist carrying current more than their surrounds, like the silicic alteration found in the core of porphyry deposits.
ZTEM surveys are different to other commercial EM systems because they measure variations in naturally-occurring EM fields rather than introducing an EM field into the ground and measuring the responding field, like VTEM.
Instead, ZTEM measures variations in the naturally-occurring or passive magnetic fields produced by thunderstorms around the world. This magnetic field is planar – constant in all directions – but areas of highly conductive or very resistive rock will cause measurable disruptions.
ZTEM surveys are designed to map resistivity contrasts to great depths, exceeding 1-2km, making ZTEM well-suited to finding porphyry-hosted and structurally-controlled exploration targets at depth.

What does a ZTEM survey look like?

The ZTEM system is transportable, able to be packed into small units which can be shipped around the world. There are two key pieces of equipment to the system, an airborne loop and ground receivers.
The airborne loops can be towed behind a helicopter or a fixed wing aircraft. The loop itself is a little over 7m across and looks a little like a giant, red-rimmed spider web. It is towed behind the aircraft at a height of around 100m above the ground to measure the vertical component of the magnetic field.
A 75-90m cable attaches the loop to the aircraft. The cable separates the loop from the vibrations of the aircraft and transmits the collected information back to the receivers in the plane or helicopter.
On the ground, base stations are set up in the survey area to measure variations in the horizontal magnetic fields.
GPS receivers are used on the coil in the air and also on the ground to keep track of the orientation of each of the parts, with respect to each other and the earth’s magnetic field.

A few Geotech case studies

Copper-porphyry, Alaska, USA
ZTEM was tested over a section of the world-class Pebble calc-alkalic copper-gold molybdenum porphyry deposit located in the Bristol Bay region of southwest Alaska in 2010. Some of the richest parts of the Pebble deposit are buried under up to 600 m of volcanic and sedimentary cover.
With careful processing, ZTEM was able to identify several of the distinctive alteration haloes found around the porphyry deposits, with more detail at depth than other systems.
ztem pebble Hunting for Giants: An Introduction to ZTEM Surveys in Mineral Exploration exploration methods ZTEM vtem uranium kimberlite exploration Geotech electromagnetism copper porphyry airborne geophysics
2D Resistivity cross-section over Pebble porphyry deposit in Alaska (Geotech)
Uranium deposits, Athabasca Basin, Canada
ZTEM tests were flown over unconformity-type uranium deposits in northern Saskatchewan, Canada, in 2008. The results correlated with known geological features to below 500m depth, penetrating through the thick cover materials to identify defining features in the basement rocks.
Kimberlites, Northwest Territories, Canada
A ZTEM survey flown over the Drybones Kimberlite near Yellowknife in NWT, Canada, was able to differentiate between diatreme (consolidated kimberlite) and the host rock buried under 100m of conductive cover sediments.

Further reading

The best place for information about ZTEM is the Geotech website, especially the ZTEM case study page

Several ZTEM case studies have also been published in peer-reviewed journals, for example:


Unlocking Australia’s hidden mineral potential with geophysics

Posted by on Friday, 1 August, 2014

Dr Richard Blewett:

“It is becoming increasingly difficult to discover near-surface mineral resources in Australia. New and innovative products and techniques are being developed as part of the UNCOVER Initiative to help attract mineral exploration investment that has the potential to lead to the discovery of new resources.”

One of the focus regions for the UNCOVER Initiative is the Thomson Orogen: “The Thomson Orogen is a large area that lies to the north and west of the Lachlan Orogen in New South Wales, South Australia, the Northern Territory and Queensland. Much of it is under the cover of younger sedimentary basins, with some up to several kilometres thick, and it is therefore a poorly understood element of Australia’s geology.

The southern Thomson Orogen is true ‘greenfields’ country. Although the mineral potential of the region is largely unknown, the northeastern Thomson Orogen (for example Thalanga, Charters Towers) and the similar-aged Lachlan Orogen to the south are well mineralised (for example Cadia, Northparkes, Lake Cowall Cobar). In order to attract exploration investment into the southern Thomson Orogen, and also to improve the geological understanding of the area, Geoscience Australia, the Geological Survey of Queensland and the Geological Survey of New South Wales have commenced a collaborative project to collect new (and synthesise existing) pre-competitive data.

One of the first steps in this collaboration is to acquire airborne and ground geophysical data including airborne electromagnetics (AEM), gravity and magnetotelluric (MT) data. Regional AEM data has now been collected to map cover thickness and assess the geology and prospectivity of the Southern Thomson Orogen across the New South Wales-Queensland border around Hungerford and Eulo. These data will be interpreted using existing borehole stratigraphic data and a new solid geology compilation of the region developed between Geoscience Australia, the Geological Survey of Queensland and the Geological Survey of New South Wales.

 

The Geotech VTEM FullWaveForm
airborne electromagnetic acquisition
system used in the Southern Thomson
Orogen airborne electromagnetics survey.
Image credit: Geotech Airborne Limited.

 

 

 Geoscience Australia is a leading promoter of AEM surveying for regional mapping of cover thickness, under-cover basement geology and sedimentary basin architecture. Geoscience Australia flew three regional AEM surveys during the 2006-11 Onshore Energy Security Program (OESP): Paterson (Western Australia, 2007-08); Pine Creek-Kombolgie (Northern Territory, 2009); and Frome (South Australia, 2010) [1]. The surveys were primarily designed to provide reliable, fit-for-purpose pre-competitive AEM data for mapping critical features of uranium mineral systems.

Results from these surveys have now produced a new understanding of the architecture of critical mineral system elements and mineral prospectivity for a wide range of commodities of these regions and includes details on the thickness and character of the regolith, sedimentary basins and buried basement terrains. The data have since been found suitable not just for uranium, but for mapping a range of other mineral systems including gold, silver, copper, lead, zinc and potash, as well as for under-cover geological mapping and groundwater resource estimation.

The survey data are now processed using the National Computational Infrastructure (NCI) facility at the Australian National University to produce GIS-ready interpretation products and GOCADTM objects suitable for 3D modelling.

A number of 3D models are being developed to interpret the near-surface under-cover geology of cratons and mobile zones, the unconformity surfaces between these and the overlying sedimentary basins, and the architecture of those basins. These models are constructed primarily from AEM data using stratigraphic borehole control and show how AEM data can be used to map the cross-over area between surface geological mapping, stratigraphic drilling and seismic reflection mapping. These models can be used by minerals explorers to more confidently explore in areas of shallow to moderate sedimentary basin cover by providing more accurate cover thickness and depth to target information. A 3D model of basement-cover relationships and depth of cover will be developed for the southern Thomson Orogen.”


Advanced airborne geophysics technologies for new industry development and innovations in Kazakhstan

Posted by on Tuesday, 8 July, 2014

2 July 2014 – Astana, Kazakhstan

The President of Kazakhstan and the Government took part in the  meeting-report of the Ministry of Industry and New Technologies in the new high tech building “Nazarbayev Cener” (project of famous British architect Norman Foster) in Astana.

Astana- Nazarbayev Center

 

 

 

 

 

 

 

 

 

 

 

 

 

(“Nazarbayev Center”,  Astana)

Geotech Ltd., a world leader of airborne geophysics had been presented to the government, Prime Minister and the President. “Kazgeology” as a part of the Ministry is going to work together with Geotech Ltd. for geophysical surveying of Kazakhstan territory and providing the airborne geophysical service for exploration and mining companies in Kazakhstan and other countries of Central Asia.

Geotech-PresidentKazakhstan

(Keith Fisk, Managing Director of Geotech with the President Nursultan Nazarbayev)

GT-Minister

 

 

 

 

 

 

 

 

 

 

 

 

 

(with the Minister of Industry)

GT-clients

 

 

 

 

 

 

 

 

 

 

 

 

 

(future surveys discussions with Rio Tinto and Iluka Resources)

GT-interview

(Keith Fisk, Managing Director of Geotech  interview to central TV channel)

 

 

 


Geophysical Survey helicopter in promotional filming at Elko Regional Airport

Posted by on Tuesday, 24 June, 2014

ELKOGeotech takes to the air to figure out what’s underground with its geophysical surveys.

On Monday, a AW-119 “Koala” helicopter and an 85-foot geophysical survey apparatus were at Elko Regional Airport to film promotional footage for Geotech. The film crew works for Cineplex, a company based in Canada.

Geotech specializes in airborne geophysical survey systems, according to Field Operations Manager Darren Tuck. The company’s clients are usually mineral exploration businesses that are interested in starting up a mine, and use the survey to find promising mineral deposits, including coal, silver, iron and copper.

Tuck said an apparatus carried by a helicopter will produce an electromagnetic pulse into the ground it flies over. Those pulses reflect off magnetic readers, and Geotech makes a map of the area after the process.

“It provides our client with a map of what the underlying layers of a structure looks like,” Tuck said.

Geotech is a global company based in Canada. Tuck said the company has worked for local mines, although he wouldn’t name any of the company’s clients in order to protect their confidentiality.

Tuck said the Elko airport was selected as the location to film Geotech’s equipment, known as Versatile Time Domain Electromagnetic surveying. Tuck said Geotech has more than 30 VTEMs. The apparatus comes in a variety of sizes.

For information, visit www.geotech.ca.


Supervised Neural Network Targeting and Classification Analysis for Mineral Exploration

Posted by on Tuesday, 29 April, 2014

Karl Kwan (Geotech LTD) presented at Canadian Exploration Geophysical Society meeting (8 April 2014) methodology and examples of using Neural Network Targeting and Classification at mineral exploration.

“Geophysical survey contractors routinely offer multi-parameter data to clients. For example, a helicopter-borne survey may acquire Time-domain electromagnetic (TDEM), magnetic gradiometer and even gamma-ray spectrometer data (i.e., VTEMplus, Geotech LTD). Exploration geophysicists can certainly take advantage some of the readily available multi-disciplinary (geology, geophysics and remote sensing) and multi-parameter (potential field, EM, gamma-ray spectrometry, and others) datasets for mineral exploration. However, the integration and interpretation of these datasets can be time-consuming and even challenging, especially for large-scale datasets covering large areas with diverse geological conditions. The Supervised Neural Network (NN) Targeting and Classification technique for mineral exploration described and demonstrated by Reford, Lipton and Ugalde, 2004, “Predictive Ore Deposit Targeting Using Neural Network Analysis” (http://www.pgw.on.ca/downloads.html), can be a useful and promising tool for the analysis of multi-disciplinary and multi-parameter data.

In this presentation, the properties or responses of the two feed-forward multilayer Neural Networks, Levenberg-Marquardt (NN with LM training) and Fast Classification (FCNN), as implemented in the current version by PGW, are studied in detail. The supervised NN simulations are performed on specially constructed synthetic data. Intended as a tutorial and the NNs treated as black boxes, the objectives of the exercise are twofold, to demonstrate the targeting as well as classification capabilities of the Neural Networks, and at the same time to show one of the known limitations and to suggest a way to get around it. The utility of the NN tool is demonstrated again with real cases from the Republic of Niger.”

Geosoft is delighted to host the online portion of the Canadian Exploration Geophysical Society meeting with keynote speaker Karl Kwan, Geotech LTD.

YouTube:  


World class geophysics for Republic of Kazakhstan

Posted by on Sunday, 6 April, 2014

April 3, 2014, Astana. Vice Minister of Industry and New Technologies of the Republic of Kazakhstan Nurlan Sauranbayev and Chairman of the Board of JSC “Kazgeologiya” Galim Nurzhanov met with the Ambassador of Canada Stephan Millar and leading world class Canadian geophysical companies Phoenix Geophysics and Geotech Ltd.

“I want to thank you for the meeting. I see great potential for fruitful cooperation in the field of exploration, “- said Stephen Millar. Vice Minister of Industry and New Technologies Nurlan Suranbaev suggested for further cooperation JSC “Kazgeologiya”, which held preliminary talks with the companies.

 

 

 

 

 

 


Recent investigations of geophysics abilities in aquifer mapping and resource evaluation

Posted by on Thursday, 13 March, 2014

Buried beneath the glaciated terrain, valleys filled with coarse-grained permeable sediments  potentially are great sources of fresh ground water. During the last several years Geological Survey of Canada has been investigating geophysical methods potential, particularly airborne electromagntics, for mapping and resource evaluation of buried valleys.   Spiritwood valley aquifer in southern Manitoba has been chosen for the investigations. Heliborne AeroTEM, VTEM, fixed-wing TEMPEST and MULTIPULSE, ground electrical resistivity and time-domain methods, seismic reflection and borehole data have been involved into the complex analysis. Recently collected ground TEM data for Spiritwood and the report (G.A. Oldenborger and K. Brewer, 2014) has been released: http://geoscan.nrcan.gc.ca/starweb/geoscan/servlet.starweb?path=geoscan/fulle.web&search1=R=293700.

One of the successful heliborne TEM examples (Legault, J.M., Prikhodko, A., Dodds, D.J., MacNae, J.C., Oldenborger, G.A., 2012. Results of recent VTEM helicopter system development testing over the Spiritwood Valley aquifer, Manitoba. Symposium on the Application of Geophysics to Environmental and Engineering Problems. Environmental and Engineering Geophysical Society, 114–130.):

VTEM-ground

 

 

 

 

 

 

 

 

 

 

 

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Another recent example of the results of a combined seismic and airborne electromagnetic (AEM) interpretation of the shallow Quaternary sedimentsand  bedrock but in British Columbia (Horn River Basin) was presented on Geoconvetion-2013  .

 

 


High Resolution Airborne Geophysical Survey in Tanzania

Posted by on Sunday, 19 January, 2014

Geological Survey of Tanzania (GST) and Ministry of Energy and Minerals of Tanzania have organized the Workshop “Launching High Resolution Airborne Geophysical Data at Julius Nyerera Convention Center (17 January, 2014, Dar es Salaam, Tanzania). Around 150 delegates have attended the workshop from government and private sectors.

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Geotech Ltd. and Sander Geophysics have finished the airborne magnetic, gravity, electromagnetic (VTEM), radiometric surveys in 31 districts and presented some results of the surveys.

Permanent Secretary (PS) of Ministry of Energy and Minerals Mr.Eliakim Maswi said – the surveys were carried out under the Sustainable Management of Mineral Resources Project, saying the purpose of the survey was to identify potential zones of mineralization. “The main objective of the project is to improve the socioeconomic impacts of mining for Tanzania and Tanzanians and therefore enhance local and foreign investments”, said PS.

GST Chief Executive Officer , Prof. Abdulkarim Mruma said: “geophysical data acquired through the high resolution airborne geophysical surveys allow fast and accurate delineation of mineralised targets and when augmented with geological and geochemical datasets are highly effective in attracting new exploration ventures.” Prof. Mruma noted that the availability of the modern geo-scientific  data will stimulate investments into mineral and other sectors and will improve the effectiveness of exploration programs.

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Photo: A.Prikhodko


Linking Porphyry Deposit Geology to Geophysics via Physical Properties

Posted by on Tuesday, 7 January, 2014

Geoscience BC Releases the Report:

Linking Porphyry Deposit Geology to Geophysics via Physical Properties: Adding Value to Geoscience BC Geophysical Data
by Dianne Mitchinson, MDRU; R.J. Enkin, GSC; and C.J.R. Hart, MDRU.

Regional geophysical surveys were flown in 2007 and 2008 as part of the QUEST and QUEST-West projects to improve geological understanding in Quaternary sediment-covered areas and thereby encourage mineral exploration. As part of the ongoing process of adding value to Geoscience BC datasets, Project 2009-001, “Integrated Geological & Geophysical Porphyry Models: Adding Value to Geoscience BC Geophysical Data (NTS 93E, 93K, 93L, 93M, 93N)” was undertaken to define relationships between geophysical datasets collected as part of these QUEST surveys and porphyry deposit geology at six known porphyry deposits. The deposits chosen for investigation include: Mount Milligan, Endako, Huckleberry, Bell, Granisle and Morrison. 
Geoscience BC Report 2013-14 presents physical rock property data from the six above-listed BC porphyry deposits, and discusses observed trends within the detailed QUEST and QUEST-West geophysical datasets and mapped geology. The resulting physical rock property data compilation has implications for improving interpretations of geophysical data from porphyry deposits. A synopsis of physical property criteria defining hydrothermally altered or mineralized rocks in BC porphyry settings is provided, which can ultimately be used for ranking similar mineral exploration targets throughout BC, thereby minimizing exploration risk.

GBC_Report2013-14a

 

 

 

 

 

 

 

 

 

 

 

Porphyry deposits surveyed during the QUEST and QUEST-West projects include Mount Milligan, Endako, Huckleberry, Bell, Granisle, and Morrison. Airborne magnetic and electromagnetic surveys (VTEM or AeroTEM) were conducted over each of these deposits. Additionally, a ZTEM (Z-axis tipper electromagnetic) survey was completed over the Mount Milligan deposit as a joint initiative between Geoscience BC and Terrane Metals Corp.

2009 : AeroTem Survey Results from the Equity Silver Mine
– Mineral Exploration Roundup Poster (pdf, 3.96MB)

Technical Article: 2009: “QUEST-West Geophysics in Central British Columbia (NTS 093E, F, G, K, L, M, N, 103I): New Regional Gravity and Helicopter-Borne Time-Domain Electromagnetic Data”
– Summary of Activities 2008, Report 2009-1 p.1-6 (pdf, 4.64MB)

 

 

 

 

 

Geophysical Surveys

 

 

Technical Article: 2007 : “Airborne electromagnetics and airborne gravity in the QUEST Project area, Williams Lake to Mackenzie, British Columbia (parts of NTS 093A, B, G, H, J, K, N, O; 094C, D)”
– Summary of Activities 2007, Report 2008-1 p.1-6 (pdf, 6.81MB)

Suggested Reference: Mitchinson, D.E., Enkin, R.J., and Hart, C.J.R. (2013): Linking Porphyry Deposit Geology to Geophysics via Physical Properties: Adding Value to Geoscience BC Geophysical Data; Geoscience BC, Report 2013-14, 116 p.

Report Components


VTEM09 VMS Prospect in Northern Ethiopia drilling results

Posted by on Tuesday, 23 July, 2013

Tigray Resources Inc. announces assay results from preliminary diamond drill-hole tests of the VTEM09 VMS Prospect on the Harvest Property and the Adi Gozomo Gold target on the Adyabo Project, in Northern Ethiopia. Single diamond drillholes tested both targets as an initial appraisal of prospectivity.

The results include:

  • 10.69 metres grading 3.47% copper, 4.2 grams per tonne gold, 3.69% zinc, and 91 grams per tonne silver from 19.81 metres, including 3.06 metres grading 5.75% copper, 8.00 grams per tonne gold, 0.70% zinc, and 107 grams per tonne silver (TVD001), at VTEM09
  • 7.5 metres grading 2.04 grams per tonne gold from 15.1m (AD001) at Adi Gozomo.

VTEM09 prospect

The high-grade copper and precious-metal enriched VMS mineralization intersected by TVD001 compares favourably with the metal tenor encountered at the Terakimti and Mayshehagne discoveries, and marks the third significant VMS discovery made at Harvest.

The VTEM09 prospect, located 5 kilometres ENE and along strike of Terakimti, was identified by an Airborne VTEM survey, and is characterized by a >200m strike length bedrock conductor. VTEM09 was further defined through mapping, soil sampling and trenching (refer to Tigray’s news release dated Jan 24th, 2013), and is interpreted to be a southwest-dipping, eastward-plunging mineralized VMS shoot. Additional drilling is required to test this prospect along strike, down dip and down plunge.

Adi Gozomo

One short diamond drillhole was targeted below the main artisanal workings, and encountered gold mineralization associated with the upper contact of a granodiorite hosted within mafic volcanic rocks. As the results to date indicate that gold mineralization appears directly proportional to the amount of pyrite present, additional ground exploration will be required prior to further drill testing at Adi Gozomo.

Diamond Drill Hole Results

DDH ID From (m) To (m) Interval (m)* Copper (%) Au (g/t) Ag (g/t) Zn (%) Prospect
TVD001 19.81 30.50 10.69 3.47 4.20 91 3.69 VTEM09
including 21.34 24.40 3.06 5.75 8.00 107 0.70
AD001 15.10 22.60 7.501 0.00 2.04 0 0.00 Adi Gozomo

* Intersection true widths are estimated at 60-90% of interval stated.

The Map


Airborne EM shows deep conductor extending to 1500 m depth

Posted by on Thursday, 20 June, 2013

Precious Metal Resources has opened up the potential for very deep mineralisation throughout its Halls Peak Base Metal Province in New South Wales, Australia) after reprocessing VTEM data.

The reprocessing by CD3D clearly demonstrated two electrically conductive beds with the deep bed, which had previously been mapped by electromagnetic surveys to depths of 400 metres, now interpreted as extending up to 1,500 metres deep.

Two examples of these beds are shown below:

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This deep bed does not crop out, and its nature is uncertain, as such conductive beds can be produced by several factors. These include sulphide mineralisation, which may include lead copper-silver sulphides, graphitic shales, magnetite bearing rocks.

Mapping to those depths strongly suggests continuity of the deep electrically conductive horizon between previously isolated districts, including the Long Point area, the Halls Peak area, and the Raspberry Road area.

Should this deep electrically conductive bed be produced by base metal mineralisation, the reinterpretation opens up potential for very extensive deep mineralisation throughout this province.

The shallow electrically conductive bed crops out in several places, where beds and pods of high-grade base metal mineralisation were mined within black shales

Past drilling and mining at Halls Peak has been too shallow to reach the potential high-grade lenses, instead intersecting either less mineralised beds within the overlying black shales, or high grade near surface mineralised fractures.

Screen dump of deep (500 mto 1000 m) conductance:

CD3D’s report states:

“Two extensive, sub-horizontal conductive bands were detected, one near surface and one mostly below 500 m. Map images of interval conductances are provided separately (“Stop50”), for the top 50 m and the 50 to 100m depth range, (“S50to100”), as well as for the 50 m to 500 m depth range, then for the 500 m to 1000 m range, and finally the 1000 m to 1500 m depth range. All the conductance maps have the same colour scale, with blue resistive and red conductive. A few conductive zones are fairly well imaged as seen in the following screen dumps.”

Details…


Airborne EM for VMS on ARMSTRONG BROOK PROJECT, NEW BRUNSWICK

Posted by on Friday, 31 May, 2013
The 2013 exploration program on the Armstrong Brook project commenced in early May. Highlights include the discovery of additional clusters of high-grade massive sulphide boulders in multiple locations (namely VMS Valley 4 & 5) and the completion of an airborne geophysical survey (VTEM) that identified intriguing anomalies in the vicinity of the primary boulder clusters.
The Armstrong Brook project comprises a number of high-grade polymetallic volcanogenic massive sulphide (VMS) prospects located in the Bathurst Mining Camp of northeastern New Brunswick, situated approximately 15 kilometres northwest of the Brunswick No. 12 Zn-Pb-Ag-Au deposit. Brunswick No. 12 is one of the world’s premier VMS deposits, having produced zinc, lead, silver and gold over a mine life of some 60 years.
VMS Valley 4:
The new discoveries at VMS Valley 4 occur as 2 boulder clusters located approximately 300 metres apart. Samples from the first cluster (AR13-0007-1 and 2) and the second cluster (AR13-0008-1 through 6), have returned high-grade mineralization with combined zinc+lead average assays of 13.68% and 10.33%, respectively, with impressive precious-metals as high as 459 grams per tonne silver and 1.07 grams per tonne gold. Complete assay results from the new boulder discoveries .
VMS Valley 5:
Additional prospecting has been completed in the vicinity of a recently discovered cluster of boulders located in the northwestern portion of the property. This work resulted in the discovery of 5 massive sulphide boulders in the vicinity of a discovery reported earlier in 2013, that yielded high-grade results with assays of up to 13.07% Zn, 6.07% Pb, 0.76% Cu, 251 g/t Ag and 0.66 g/t Au (see Wolfden news release dated March 20, 2013). These discoveries occur over an intermittent strike length of close to 700 metres and occur coincident to a significant geophysical anomaly that was identified in the recently completed VTEM airborne geophysical survey.
Assays remain pending for the new massive boulders from VMS Valley 5.
Preliminary results obtained from the VTEM survey indicate that the massive sulphide boulders are intimately associated with the eastern margin of a strong electromagnetic anomaly (EM conductor). This hook-shaped conductor attains a strike length of approximately 2 kilometres (see Image 1). Additionally, the cluster of massive sulphide boulders at VMS Valley 5 is centred within a broad circular-shaped magnetic high (total magnetic intensity) that has a radius of approximately 2.5 kilometres (see Image 2). Clearly, this anomaly requires detailed follow-up in the way of ground geophysical surveys prior to diamond drilling.

The 2013 exploration program on the Armstrong Brook project commenced in early May. Highlights include the discovery of additional clusters of high-grade massive sulphide boulders in multiple locations (namely VMS Valley 4 & 5) and the completion of an airborne geophysical survey (VTEM) that identified intriguing anomalies in the vicinity of the primary boulder clusters.The Armstrong Brook project comprises a number of high-grade polymetallic volcanogenic massive sulphide (VMS) prospects located in the Bathurst Mining Camp of northeastern New Brunswick, situated approximately 15 kilometres northwest of the Brunswick No. 12 Zn-Pb-Ag-Au deposit. Brunswick No. 12 is one of the world’s premier VMS deposits, having produced zinc, lead, silver and gold over a mine life of some 60 years.


The results of the EM/Magnetic airborne survey over the Borden Lake Extension

Posted by on Wednesday, 29 May, 2013

Nikos Explorations Ltd. announces the results of the high-resolution VTEM (Versatile Time-Domain Electromagnetic System) and magnetic airborne survey recently completed over the Borden Lake Extension by Geotech Ltd. A total of 391 line kilometers were flown to cover the Property. The VTEM and magnetic surveys were completed in order to identify electromagnetic and magnetic anomalies that may be associated with gold mineralization and to help in the geological interpretation of this underexplored area.

Results of the surveys indicate electromagnetic and/or magnetic anomalies in four areas of interest (see map at http://nikosexplorations.com/projects/borden_lake/) described below in order of priority for follow up:

1. Several magnetic lineaments, one of which is interpreted to be a fault, intersect near the boundaries of claims 4260529 and 4260530. Such lineaments can reflect structures that are known to be important in the transport of gold-rich fluids. A north-east south-west lineament, apparent on a shaded relief map of the region, also crosses the Nikos claims in this area giving further reason for follow up.

2. Cross cutting NNW-SSE and NE-SW trending positive magnetic anomalies in claim 4259808 may represent major structures. There are also coincident weak electromagnetic anomalies that could indicate the presence of sulphide.

3. Similar cross-cutting magnetic anomalies and electromagnetic anomalies seven to eight hundred metres east of 2, but not as strong.

4. This area in the east of the property is characterised by a small positive magnetic anomaly with a coincident electromagnetic anomaly.

Nikos is planning a follow up program of mapping, sampling and prospecting to investigate the cause of the anomalies.

The Borden Lake Extension Project is located near the town of Chapleau, Ontario in an area of good infrastructure including road, rail and power. It covers an area of 1,598 hectares immediately east of Probe Mine’s Borden Lake gold property where recent exploration has defined pit constrained indicated resources of 3,686,000 ounces of gold (112.8 M tonnes grading 1.02g/t gold) and inferred resources of 625,000 ounces of gold (18.04 M tonnes grading 1.08g/t gold) at a 0.5g/t cutoff grade. This is the first discovery of significant gold in the Kapuskasing Structural Zone.

The Borden Lake Extension property covers Archean aged metamorphic rocks in an underexplored portion of the Kapuskasing Structural Zone.

Nikos is planning an airbourne geophysical survey using VTEM (versatile time domain electromagnetics) and magnetics to explore for Borden Lake type gold mineralization. Gold at Borden Lake is associated with a continuous zone of disseminated sulphide (pyrite and pyrrhotite) mineralization that gives rise to electromagnetic anomalies. The airbourne survey is expected to be completed during the first quarter of 2013.


Airborne Geophysical Survey Along Trend Of The Alpha/Fission Patterson Lake Discovery

Posted by on Tuesday, 28 May, 2013

Forum Uranium Corp. announces the commencement of an electromagnetic and magnetic survey of its 100% owned Clearwater Project. Forum’s claims, staked immediately adjacent to the southwest of the Alpha Minerals/Fission Uranium claim boundary is interpreted to be on strike with the fertile conductive trend that hosts the high-grade uranium discovery on the Patterson Lake South project. Forum’s property lies only four kilometres southwest of the high grade boulder train on the Alpha/Fission property.

Figure shows historical electromagnetic trends, a magnetic map and lake sediment geochemical surveys in the Patterson Lake South area. The electromagnetic (EM) surveys stopped at Forum’s claim boundary, however EM conductors from these historic surveys trend in the direction of Forum’s ground. Of particular note is that the highest lake sediment value in the area lies on Forum’s southwest claim with a value of 8.3 ppm U. Most values are between 1 to 3 ppm U and the lake sediment sample taken down-ice from the Patterson lake boulder field was 3.2 ppm U.

An Aeroquest Airborne helicopter-borne time domain electromagnetic survey with Bfield-VTEM Plus and magnetic gradiometer system will be flown on 200 metre line spacings for a total of 647 line kilometres over Forum’s 99 square kilometre property. The VTEM Plus system has been chosen for its depth penetration and vertical/spatial resolution of graphitic conductors that are prospective hosts for unconformity-style uranium deposits.

This is the first phase of this year’s summer exploration program. Plans are to conduct an airborne radiometric survey and a detailed prospecting survey to search for any boulder fields similar to that found on the Alpha/Fission ground.