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Ministry of Energy Mines and Responsible for Core Review
The MapPlace - Toodoggone Geophysics
and Geology Map

(BCMEM OF 2004-8 / GSC OF 4606 - 4613)

MapPlace Home

Details:  The Toodoggone map features new multisensor, airborne geophysical surveys, which includes 2 magnetic and 8 radiometric parameters.  The files are also available for download in georeferenced TIF and PNG formats and GeoSoft gridded data (.grd) format.  The 2003 surveys, including the Horsefly/Mount Polley Geophysics, were posted to MapPlace March 26, 2004.

View Toodoggone Geophysics Map

Toodoggone Geophysics Map


Survey Background


TOODOGGONE MULTISENSOR GEOPHYSICAL SURVEY
Open File 2004-8
Helicopter-borne gamma ray spectrometric and magnetic total field geophysical survey, Toodoggone Area, British Columbia
(Parts of NTS 94D/15, E/2,3,6,7,10,11)
R.B.K. Shives, J.M. Carson, K.L. Ford, P.B. Holman, L. Diakow

In 2003 the BC Ministry of Energy, Mines and Petroleum Resources and the Geological Survey of Canada conducted a multisensor (gamma-ray spectrometric, magnetic total field) helicopter-borne geophysical survey in the Toodoggone area, British Columbia, Canada. Flight lines were oriented NE-SW, spaced at 400 m intervals. The survey was flown under contract, by Fugro Airborne Surveys. The survey was funded by the British Columbia Ministry of Energy, Mines and Petroleum Resources and Natural Resources Canada through the Targeted Geoscience Initiative, and by a consortium of companies including Bishop Resources Inc., Finlay Minerals Ltd., Northgate Exploration Ltd., Sable Resources Ltd.,and Stealth Minerals Ltd.

Purpose and Methodology

The overall purpose of the surveys is to provide modern high-definition radiometric and magnetic data that can be used in the assessment and development of targets for mineral exploration, and to assist in future bedrock and surficial mapping studies. The Geological Survey of Canada has had good results in previous multisensor surveys over similar BC porphyry deposits (e.g. Afton and Mt. Milligan). The radiometric (K and eTh/K ratio) and magnetic (total field and calculated vertical gradient) maps are particularly useful in identifying potassic alteration and magnetite enrichment/depletion zones associated with these copper-gold deposits, and in mapping bedrock lithologies and structures.

 

The surveys were completed during August and September 2003 using an Aerospatiale AS350 helicopter. The flight path was recovered using a post-flight differential Global Positioning System. A vertically mounted video camera was used for verification of the flight path. The traverse lines were flown at an average spacing of 400 m for Toodoggone, (500 m for Horsefly and 100 m for Imperial Mt. Polley) with control lines flown at 4000 m intervals (2000 m for Imperial Mt. Polley). Helicopter flight height was maintained at an average ground clearance of 135 m (60 m).

 

The gamma ray spectrometry data were recorded at a 1.0 second sample rate using a 256-channel Exploranium GR820 spectrometry system with 33.6 liters of downward-looking and 4.2 liters of upward-looking sodium iodide detectors. The aeromagnetic data were recorded at a 0.1 second sample rate using a 0.01 nT split-beam line cesium vapour magnetometer suspended below the helicopter.

 

Final results will be presented in GSC and BCGS Open File formats in May 2004. The Open Files will consist of digital data (Geosoft compatible line and gridded formats) and colour interval maps at 1:20,000 and 1:50,000 scales, for 10 layers (listed below). Map images will be presented as georeferenced .tif files for easy import into GIS programs and as .pdf files with marginal notes, legend and topographic base information. Data will be made available for purchase as digital line or grid data on CD-ROM (from GSC only), in paper format as print-on-demand colour maps from GSC (only) and as web-viewable, downloadable images in PDF format, at no cost, from BCGS and GSC websites.

 

Analogue and digital products include data for eight radiometric and two magnetic parameters:

MapPlace Layer Themes

PDF Themes Files

See Note 1

MTF - Magnetic total field (nT) T_mtf.pdf (4.1 MB)
CVG - Calculated magnetic vertical gradient (computed, nT/m) T_cvg.pdf (4.4 MB)
POT - Potassium (K, %) T_pot.pdf (4.1 MB)
URA - equivalent Uranium (eU, ppm) T_ura.pdf (4.4 MB)
THO - equivalent Thorium (eTh, ppm) T_tho.pdf (4.3 MB)
ADRN - Natural air absorbed dose rate (ADRN, nGy/h) T_adrn.pdf (4.1 MB)
RUT - equivalent Uranium/equivalent Thorium (eU/eTh) T_rut.pdf (4.4 MB)
RUK - e quivalent Uranium/Potassium (eU/K, ppm/%) T_ruk.pdf (4.4 MB)
RTK - e quivalent Thorium/Potassium (eTh/K, ppm/%) T_rtk.pdf (4.3 MB)
TER - Ternary radioelement map (K, eU, eTh) T_ter.pdf (3.9 MB)
1:250K Scale Geology, Mineral Occurrences & Titles T_geology.pdf (0.5 MB)
All Themes in one file (11 by 17 images) T_geophysics.pdf (9.8 MB)
GSC Open Files 4606 - 4612 Final Product Release
Plot size PDF 1:50K, 1:250K
File Downloads Zip Files
Georeferenced TIFF files (UTM Zone 9 NAD 83) T_tif_Z9.zip (4.3 MB)
Georeferenced TIFF files (Albers NAD 83) T_tif_AL.zip (4.0 MB)
Georeferenced PNG files (UTM Zone 9 NAD 83) T_png_Z9.zip (2.3 MB)
Georeferenced PNG files (Albers NAD 83) T_png_AL.zip (2.2 MB)
Original GSC SurView data files for viewing and printing only (.gri & .grx) T_gri.zip (8.4 MB)
Original GSC GeoSoft gridded data format (.grd) T_grid.zip (7.6 MB)
Original GSC Ternary data (.bil), see Note 2 T_ternary.zip (1.0 MB)

Note 1: The PDF maps were created from MapPlace using the Rasterize print job option to eliminate the black background. The TIF and PNG download images include the geophysical information without topographic base information.

Note 2: To display the Ternary images using Geosoft's Oasis Montaj the following instructions will yield the best results.

bullet In Oasis, select the grid pulldown menu.
bullet select Display grid as Ternary image
bullet Colour model must = RGB
bullet Colouring method must = Linear
bullet The three colour component files must be opened as Files of Type BIL with *.hdr header.
bullet Red-Cyan = TERURA_C.BIL
bullet Green-Magenta - TERPOT_M.BIL
bullet Blue-Yellow = TERTHO_Y.BIL
bullet Shading grid = nothing
bullet Shading grid colouring method = Linear
bullet To display the triangular Ternary Legend select Display grid - Ternary Legend
bullet Colour model must = CMY

If these instructions are not followed, the resulting image will be a three colour image but not the intended GSC style image. These ternary images should not be treated as data. The derivation of the colours involves multiple histogram equalizations.

Legend:

K - potassium, i.e. K40 (units: %)
eU - equivalent uranium concentration by weight (the spectrometer directly measures Bi214, that is an indirect measure of uranium) (units: ppm)
eTh - equivalent thorium concentration by weight (the spectrometer directly measures Tl208, that is an indirect measure of thorium) (units: ppm)
Total Count - all counts from 400 to 3000 keV. (units: cps or uR/h)
Natural Exposure - computed from K (%), eU (ppm), eTh (ppm) concentrations:
Exposure = 1.505 K + 0.625 eU + 0.31 eTh (uR/h)
(Grasty et al, 1984) 'Exposure' is different from the traditional 'Total Count', in that it excludes radiation from man-made contaminants.
Natural Air Absorbed Dose Rate - computed from K (%), eU (ppm), eTh (ppm) concentrations:
Absorbed Dose Rate = 13.08 K + 5.43 eU + 2.69 eTh (nGy/h) 'Natural Air Absorbed Dose Rate' is different from the traditional 'Total Count', in that it excludes radiation from man-made contaminants.
eU/eTh, eU/K, eTh/K - ratios of K, eU, eTh that are useful for interpretation

Units:

nT - unit of magnetic total field (nano Tesla)
ppm - unit of concentration by weight (part per million), used for eU (uranium) and eTh (thorium)
% - for potassium (K40): unit of concentration by weight
Ur - unit of radioelement concentration by weight
(1 Ur is defined as the total count rate from 1 ppm uranium in equilibrium)
µR/h - unit of Exposure (micro Roentgen/hour)
nGy/h - unit of Natural Air Absorbed Dose Rate (nano Gray/hour)

British Columbia Mineral Tenure Information

Clients are reminded that accurate and up-to-date mineral tenure maps are the paper (counter) maps at the Mining Recorder's (Government Agent) offices. The claim information on the MapPlace MTO layer is current to the previous day.  The PDF maps (Ministry of Sustainable Resource Management) are out-of-date and should not be relied upon for staking decisions.

 

The Toodoggone survey is within the Omineca and Liard Mining Divisions and maps are available from the Mining Recorder's offices in Smithers (Omineca MD) and Vancouver (Liard MD).

 

The BCGS (TRIM) claim maps relevant for the Toodoggone Geophysical Surveys are:  094D.087, 097; 94E.006-007, 014-017, 024-027, 033-037, 043-047, 053-056, 065.

Locations to View Paper Maps

Vancouver Mineral Development Office, BC Ministry of Energy and Mines
300 - 865 Hornby Street, Vancouver, B.C.
Contact Bruce Northcote, Regional Geologist,           604 660-2812        
or Larry Diakow, Senior Project Geologist,               250 952-0430        


Regional Operations Branch, 162 Oriole Road, Kamloops, B.C.
Contact: Jim Britton, Regional Geologist,                250 371-3903        


Regional Operations Branch, 350-1011-4th Avenue, Prince George, B.C.
Contact: Regional Geologist, Paul Jago,                   250 565-4132

        

For information contact


BC Geological Survey
Telephone: (250) 952-0372 Fax: (250) 952-0381
 

website: http://www.empr.gov.bc.ca/Mining/Geoscience/ 

 

 

* * * FINAL PRODUCT RELEASE * * *

The Geological Survey of Canada and the BC Ministry of Energy & Mines provided multisensor geophysical survey data for these surveys available in variety of digital and printed formats in January 2005:

 

1. Available from GSC offices in Vancouver & Ottawa on demand

bullet 1:50 000 scale colour interval, hardcopy maps
bullet 1:250 000 scale colour interval hardcopy maps

2. Available from GSC Offices in Vancouver and Ottawa or download from MapPlace:

bullet Digital images of colour interval maps on CD-ROM in Portable Document Format (PDF).
GSC Open File 4613 (Plot size PDF 2 to 7 MB) Read me 1:50K 1:250K
MTF - Magnetic total field (nT) 94E:10/11, 7, 6, 3, 2 94D:15 4612_09.pdf (3.2 MB)
CVG - Calculated magnetic vertical gradient (computed, nT/m) 94E:10/11, 7, 6, 3, 2 94D:15 4612_10.pdf (3.6 MB)
POT - Potassium (K, %) 94E:10/11, 7, 6, 3, 2 94D:15 4612_02.pdf (3.3 MB)
URA - equivalent Uranium (eU, ppm) 94E:10/11, 7, 6, 3, 2 94D:15 4612_03.pdf (3.6 MB)
THO - equivalent Thorium (eTh, ppm) 94E:10/11, 7, 6, 3, 2 94D:15 4612_04.pdf (3.5 MB)
ADRN - Natural air absorbed dose rate (ADRN, nGy/h) 94E:10/11, 7, 6, 3, 2 94D:15 4612_01.pdf (3.3 MB)
RUT - equivalent Uranium/equivalent Thorium (eU/eTh) 94E:10/11, 7, 6, 3, 2 94D:15 4612_05.pdf (3.7 MB)
RUK - e quivalent Uranium/Potassium (eU/K, ppm/%) 94E:10/11, 7, 6, 3, 2 94D:15 4612_06.pdf (3.6MB)
RTK - e quivalent Thorium/Potassium (eTh/K, ppm/%) 94E:10/11, 7, 6, 3, 2 94D:15 4612_07.pdf (3.6 MB)
TER - Ternary radioelement map (K, eU, eTh) 94E:10/11, 7 ,6, 3, 2 94D:15 4612_08.pdf (3.3 MB)
**Also see Analogue and Digital Products for MapPlace layer themes and file downloads.


3. Available only from the Radiation Geophysics Section in Ottawa, on demand
.

bullet Customized geophysical survey digital data on CD-ROM in a user-compatible format.