Deep Underground Science Experiment Lab

The former Homestake Gold Mine in Lead, South Dakota, was transformed into the Sanford Underground Research Facility, a laboratory for conducting multi-disciplinary science and engineering research projects, including physics experiments that require shielding from cosmogenic radiation. Schnabel was engaged early to help assess plans to construct several large cavities 4,850 feet below the ground’s surface.

The project, referred to as the Deep Underground Science and Engineering Laboratory at the time of our investigation, anticipated creating cavities approximately 160-ft wide by 180-ft tall. We conducted extensive geotechnical field mapping to collect the structural geologic data necessary to characterize the rock mass for the design and excavation of the large cavities. The data collected also included the rock mass characterization parameters needed to estimate rock quality designation (RQD) and calculate Q (NGI-Q rock quality index) and RMR (rock mass rating index).

In total, approximately 5,000 feet of drift were mapped in detail over the course of multiple phases of field work. In one phase, approximately 600 feet of mapping was conducted followed by a detailed LIDAR (light detection and ranging) laser scan to evaluate the strengths and weaknesses of each method used. At the conclusion of the investigation, we were asked to present the findings to the Large Cavity Review Board through a peer review process.