Interferometric seismic imaging around the active Lalor mine in the Flin Flon greenstone belt, Canada
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| Authors: | Roots, E; Calvert, AJ; Craven, J |
| Year: | 2017 |
| Journal: | Tectonophysics 718: 92-104 Article Link (DOI) |
| Title: | Interferometric seismic imaging around the active Lalor mine in the Flin Flon greenstone belt, Canada |
| Abstract: | Seismic interferometry, which recovers the impulse response of the Earth by cross-correlation of ambient noise recorded at sets of two receivers, has found several applications, including the generation of virtual shot gathers for use in seismic reflection processing. To evaluate the effectiveness of this passive recording technique in mineral exploration in a hard-rock environment, 336 receivers recorded 300 h of ambient noise over the volcanogenic massive sulphide deposit of the recently discovered Lalor mine in the Canadian Flin Flon greenstone belt. A novel time-domain beamforming algorithm was developed to search for individual source locations, demonstrating that the vast majority of noise originated from the mine and ventilation shafts of the Lalor mine. The results of the beamforming were utilized in conjunction with frequency-wave number filtering to remove undesirable, mostly monochromatic surface wave noise originating from nearby sources. Virtual shot gathers were generated along three receiver lines, each of which was processed as a separate 2-D reflection line. Two of the resulting unmigrated reflection profiles are compared against coincident dipmoveout-stacked data from a larger, coincident 3-D dynamite seismic survey that was also acquired over the Lalor mine in 2013. Using knowledge of the local geology derived from numerous boreholes, coherent events recovered in the passive reflection profiles are inferred to be either spurious arrivals or real reflections, some of which can be interpreted in terms of geological contacts, indicating the future potential of passive recording surveys in hard rock settings. (C) 2017 Elsevier B.V. All rights reserved. |
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