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TitleDetails and preliminary positive evaluation of a test seismic interferometry survey at an active VMS mine near Snow Lake, Manitoba
AuthorCraven, J A; Cheraghi, S; Roberts, B J; Bellefleur, G; Schetselaar, E; Melanson, D; Bancroft, B; Miah, K
SourceGeological Survey of Canada, Open File 7590, 2014, 30 pages, (Open Access)
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
File formatpdf
AreaSnow Lake; Wekusko Lake; Lalor Lake
Lat/Long WENS-100.2500 -100.0000 54.8833 54.7500
Subjectsgeophysics; economic geology; seismic interpretations; seismic surveys; seismic reflection surveys; volcanogenic deposits; sulphides; sulphide deposits; gold; silver; zinc; copper; interferometry
Illustrationslocation maps; tables; profiles
ProgramTargeted Geoscience Initiative (TGI-4), Methodological Development
Released2014 03 02
AbstractSeismic reflections methods are a powerful tool to detect and image structures associated with volcanogenic massive sulphide (VMS) deposits. Seismic interferometry has recently been developed as a robust method to process passive seismic data and image geological features. In order to test the capability of seismic interferometry to image ore deposits in the crystalline rock environment approximately 300 hours of ambient noise data covering an area of 4 km² were acquired over the Lalor mining area, near Snow Lake, MB, Canada,. The interferometry survey consisted of 336 receivers installed in a grid comprising sixteen lines. The study area encompasses the Lalor deposit, a 27 Mt VMS deposit located at a depth of ~700 m. A distinct, overlapping 3D active source seismic survey was also acquired in the area and we use it here to evaluate our interferometry results. An estimate of the seismic wave field (Green's function) is retrieved by crosscorrelating the noise between all receiver locations in each hourly segment of passive seismic data. The crosscorrelated results are summed to generate 'virtual' shot gathers at each physical receiver location. The virtual data is processed along all 2D lines with conventional methods similar to those applied to active 3D data. The DMO-stacked section obtained reveals a number of events, some more coherent than observed on the active seismic section. Of particular interest is an event possibly associated with one of the lenses associated with the massive sulphide deposit. A comparable event is also observed on the active seismic data. These results are encouraging and demonstrate the benefits of ambient noise measurements and interferometry in for mineral exploration in crystalline rock environment.
Summary(Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI-4) is a collaborative federal geoscience program that provides industry with the next generation of geoscience knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. The report presents details of and preliminary results of a unique seismic survey acquired to test a new exploration methodology for ore exploration. The new method involves monitoring the ambient seismic noise related to an active mine development project in order to map the subsurface structure and identify ore zones. Promising, early results based on comparisons with more expensive exploration methods and subsurface information are presented.