Identification and Characterization of Abandoned Mines with Partial-Waveform Methods, Transmitted-Wave Tomography, Gravity and Seismic Reflection

Session: Environmental and Near Surface Seismology: From Glaciers and Rivers to Engineered Structures and Beyond
Type: Oral
Date: 4/29/2020
Time: 11:00 AM
Room: 110 + 140
Description: 

Open workings from legacy coal mines pose risk to overlying infrastructure, but the geometry of persistent voids is generally unknown. To aid in remediation efforts (e.g., grouting), we have conducted seismic and other geophysical investigations of dozens of 19^th-and early 20^th-century mines in the Rocky Mountain region. Each site poses distinct challenges, requiring flexible application of novel techniques and combinations; this presentation highlights a few interesting examples from the past year. Despite decades of remediation, voids persist beneath the town of Hanna, Wyoming. We combined 3D grout-flow modeling with seismic reflection, transmitted P-wave velocity and attenuation tomography and gravity to identify probable open workings to depths exceeding 100 meters and thus to target boreholes for ongoing confirmation and remediation. At another undermined site in Glenrock, Wyoming, limited property access precluded first-arrival imaging of deep (>60-meter) workings. Instead, we identified partially open workings with a partial-waveform approach that isolates resonant, void-trapped waves from the latter portions of the traces. In each case, confirmation drilling and complementary geophysical surveys are ongoing, and we will discuss the relative success of these and other approaches.

Presenting Author: Will Levandowski

Authors