Emerging downhole sensing technologies for mineral exploration

Recent advancements in spectroscopic, imaging, and geophysical sensors present new opportunities to gather geological information directly during drilling, potentially reducing reliance on physical core samples. These technologies have the potential to reduce drilling costs, shorten exploration timelines, and improve decision-making in early-stage mineral exploration. This review evaluates the principles, capabilities, and limitations of emerging sensing technologies applied to mineral exploration, including hyperspectral imaging, X-ray fluorescence (XRF), gamma-ray spectrometry (GRS), borehole radar (GPR), borehole transient electromagnetic method (BTEM), muon tomography, and seismic-while-drilling (SWD). Key metrics considered include detection limits, spatial resolution, and technology readiness level. Although many of these tools are well established, their integration into drilling systems is constrained by the challenging operating conditions, including narrow borehole dimensions, high vibration, high temperatures and difficulties in maintaining reliable telemetry. By comparing the technological maturity, environmental resilience, and engineering requirements of these sensors, this review identifies GRS, and SWD as having strong potential for near-term deployment during drilling, while XRF, GPR and BTEM are likely to have a transformative impact in the longer term. Realising the full potential of downhole sensing will require substantive advances and investment in sensor miniaturization, ruggedisation for high-pressure and high-temperature environments, along with the development of reliable telemetry systems for real-time data transmission. Additionally large-scale field demonstrations will also be critical for validating system performance and enabling broader industry adoption. These advancements have the potential to transform mineral exploration by improving targeting efficiency, reducing geological uncertainty, and accelerating the transition from discovery to resource development.