Application of Seismic Frequency Resonance Technology for Karst Detection at Qingshuitang Wollastonite Mining Area of Hezhou, South China

Karst caves are among the most common and critical geological hazards in karst regions. Due to their marked differences in physical properties compared to the surrounding rock, they can be detected using various geophysical techniques. Karsts have developed on the surface of the Qingshuitang Wollastonite Mining Area in Huangtian Town, Hezhou City, Guangxi Province. In line with mine safety production requirements, a professional assessment of the potential development of karst caves must be conducted within 150 m of the mining area's surface. Following an on-site investigation and comparison with traditional geophysical methods, seismic frequency resonance technology (Seismic FRT) was selected for detection due to its convenience, flexibility, cost-effectiveness, and rapid data acquisition capabilities. Contour maps of the apparent wave impedance and geological profiles along the survey lines were obtained through data collection and processing. In combination with surface karst and mining geology, 32 karst caves (hidden danger points) and 15 karst development zones were identified. Drilling verification was conducted at the A428 and B122 anomalous points on the A1 # and B1 # survey lines. The verification results were consistent with the inferred depths and maximum apparent wave impedance anomalies, confirming that Seismic FRT is a feasible and effective method for detecting hidden karst development areas in mines.