MASW and GPR Survey to Delineate Depth‐to‐Bedrock and Crystal Cavities for Mineral Exploration, Hiddenite, North Carolina

MASW and GPR methods were used as exploration techniques to locate potential mineral deposits within a geologic setting of highly deformed metamorphic rocks overlain by lateritic soil horizons. A 24-channel land-streamer system was used to profile overlying lateritic horizons and bedrock up to depths of 100 feet. MASW survey geometry was optimized for depths up to 60 feet and high horizontal resolution. Highpowered 100-MHz bi-static antennas were used to collect data along the seismic lines as well as in areas unsuitable for the MASW method. The two exploration methods provided independently derived constraints to the bedrock depth and structural model. The GPR method was effective in identifying shallow targets in the laterite, determining depth to competent bedrock, and identifying targets within the shallow bedrock zone. The MASW 2-D shear wave velocity (Vs) profiles were useful for delineating the laterite/rock interface and identifying anomalies near the top of and within the competent bedrock zones. The data were integrated to develop a bedrock structure map and spatially delineate exploration targets.