← Back to Sessions

Challenges and Triumphs Seismic Surveying in a Historic Underground Metals Mine

Description: 

Seismic surveying within mine adits underground (e.g., >100 m) has many benefits, including the absence of low-velocity weathered overburden as well as no topography. Further, being literally immersed in the target zone means that structure and stratigraphy mapped in the adit are more readily correlated to the results of the seismic surveys. On the other hand, underground surveys present unique challenges, including logistics of deploying an energy source, emplacement of geophones in solid rock, reverberation from the adit, and safety. We present the results of seismic surveying in the Deer Trail Mine in south-central Utah (USA) discovered in 1878. The mine is located along the eastern side of the Tushar Range, which forms a transition between the Colorado Plateau to the east and the Great Basin to the west. The surveys utilized a narrow (~3x3 m) mostly horizontal adit, 120-510 m below ground surface. The country rock consists of highly fractured and mineralized Permian to Pennsylvanian quartzites, shales, and limestones. Exploration targets include shear zones and potentially reactive clean limestone intervals. A short (~375 m) test common midpoint (CMP) profile was surveyed with an accelerated weight-dropper (45 kg) energy source, using a source and receiver spacing of 3 m recorded over 96 channels. The test confirmed the ability to map very shallow (<50 m) small-scale structures, such as faults that were previously mapped in the adit. The production CMP survey covered ~1680 m with an explosive source (mostly 300 g in 1.5-m deep shot holes) recorded over 264 channels, source and receiver spacing at 6 m. A static recording array was used for both surveys with 4.5-Hz vertical geophones. The CMP profile imaged sparse horizontal and dipping reflectors down to about 500 m, tentatively interpreted as lithologic variations in the limestone or as shear zones. Our study demonstrates the potential for high-resolution seismic exploration in an unconventional and challenging setting to guide exploitation of deeply buried mineral resources.

Session: Earth’s Structure from the Crust to the Core [Poster Session]

Type: Poster

Date: 5/2/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Kevin

Student Presenter: No

Invited Presentation: 

Authors