Surface distributed acoustic sensing for mineral exploration.

Area of Science:

• Geophysics
• Mineral Exploration
• Seismic Technology

Background:

• Distributed Acoustic Sensing (DAS) is established for vertical seismic profiling but not widely used for surface reflection seismology.
• Surface DAS arrays face challenges in cost-effectiveness and successful implementation for mineral exploration due to fiber-optic cable sensitivity.

Purpose of the Study:

• To investigate the feasibility and performance of surface DAS technology for mineral exploration in a hardrock environment.
• To assess the potential of DAS for deep targeting of mineral deposits.

Main Methods:

• A fiber-optic cable was deployed on the surface above a known iron-oxide deposit in Sweden.
• The cable was lightly covered with gravel to enhance ground coupling.
• A specialized processing workflow was applied to address inherent noise in DAS data.

Main Results:

• Mineralization was successfully delineated in raw receiver gathers, despite variable data quality along the cable.
• The processing workflow enabled imaging of the iron-oxide deposit and surrounding geological structures.
• A fault system potentially responsible for deposit termination at depth was identified.

Conclusions:

• Surface DAS is a viable technology for mineral exploration, particularly for deep targeting in hardrock environments.
• Further development of DAS technology and processing workflows can overcome current limitations.
• This study justifies continued research and development for surface DAS applications in geophysics.