Broadband seismic data acquisition and processing of iron oxide deposits in Blötberget, SwedenShow others and affiliations
2025 (English)In: Geophysical Prospecting, ISSN 0016-8025, E-ISSN 1365-2478, Vol. 73, no 1, p. 80-95Article in journal (Refereed) Published
Abstract [en]
In June 2022, an innovative seismic survey was conducted in Bl & ouml;tberget, central Sweden, to evaluate the effectiveness of employing both a broadband seismic source and broadband receivers for mineral exploration in a challenging hardrock setting. The Bl & ouml;tberget mine hosts high-quality iron oxides, predominantly magnetite and hematite, sometimes enriched with apatite. These deposits comprise 10-50 m thick sheet-like horizons with a moderate eastward dip (similar to$\sim$45 degrees) along an NNE-trending zone. The survey employed a combination of co-located micro-electromechanical sensors, three-component recorders, surface and borehole distributed acoustic sensing, along with a 77-kN broadband seismic vibrator operating with 2-200 Hz linear sweeps. A tailored processing workflow was applied to preserve the broadband nature of the recorded data, and a one-dimensional velocity model was derived from the borehole distributed acoustic sensing data for migration and time-to-depth conversion purposes. Compared to the previous seismic surveys, the resulting seismic cross section reveals several well-defined reflections with improved resolution. Notably, a reflection intersecting the main deposits at a depth of approximately 1200 m exhibits a distinct polarity reversal relative to the reflection from the mineralization, providing further evidence for its interpretation as originating from a fault zone. Shallow reflections align with geological boundaries and partially coincide with weak magnetic anomalies. Additional reflections were revealed underneath the known mineralization on both sides of the fault zone and may suggest the presence of potential additional resources. The delineation of these reflections and the fault zone is critical for future mine planning and development in the region. This case study underscores the potential of broadband data in achieving high-resolution subsurface imaging in hardrock environment and its pivotal role in mineral resource assessment processes.
Place, publisher, year, edition, pages
John Wiley & Sons, 2025. Vol. 73, no 1, p. 80-95
Keywords [en]
broadband, fault, mining, mineral exploration, seismics, data processing, imaging
National Category
Geophysics
Identifiers
URN: urn:nbn:se:uu:diva-554841DOI: 10.1111/1365-2478.13648ISI: 001364933700001Scopus ID: 2-s2.0-85210520102OAI: oai:DiVA.org:uu-554841DiVA, id: diva2:1953161
Part of project
FUTURE: Fiber-optic sensing and UAV-platform techniques for improved mineral exploration, Vinnova
Funder
Vinnova, 2022-00073Swedish Foundation for Strategic Research, CMM22-0003Vinnova2025-04-172025-04-172025-04-17Bibliographically approved