Sanford Underground Research Facility (SURF): Distributed Acoustic Sensing (DAS) Array for the Monitoring of Mining and Construction Operations

ABSTRACT: At the Sanford Underground Research Facility (SURF) in Lead, SD, we deployed a Distributed Acoustic Sensing (DAS) array with mine extensions reaching from the 4100-foot to the 4850-foot levels via ramps and shafts. DAS enables highresolution spatiotemporal sensing of strain along fiber optic cables; however, DAS is intrinsically sensitive only to strains in the fiber directions, compared to the three-component particle velocity measurements used in geophones. In different deployments, we interrogated the array using an OptaSense ODH-4 unit, recording seismic wavefields from over one hundred blasts during excavation operations for three utility caverns for high-energy physics experiments at the 4850-foot level. These data capture the progression of blasts’ charge type and sequencing, source directivity, attenuation, and rock-to-fiber coupling. Our array also enables detecting local, regional, and teleseismic events while demonstrating strong sensitivity to mine activity and regional blasting. The dataset provides a valuable testbed for evaluating DAS performance in complex underground environments while monitoring mining and construction operations in deep underground settings. It also informs future array designs and DAS deployment strategies.