<p>Interference from production noises and distortion of signal by undulating terrain has been two major challenges for electromagnetic surveys in active mine. At present, no method is capable to fully eliminate the influence of these factors, but solutions exist to mitigate this predication. Leveraging the relatively quieter environment provided by underground infrastructure, the ground-tunnel observation is a novel geophysical survey method as part of frequency-domain wide-field electromagnetic methods’ practices. It transmits artificial signal on the ground surface and collects data in underground tunnels closer to the targeted ore body. Featuring higher signal-to-noise ratio and better resilience to terrain effect, this methos is advantageous in delineating deeply buried ore bodies compared to traditional surface observation when performed in active mine. To demonstrate these merits in production, this article focuses on the application of the ground-tunnel frequency-domain electromagnetic method in a production mine and conducts two-dimensional forward modeling and inversion in the field scenario. The forward modeling on synthetic models show that the tunnel observation can better capture the signal produced by the anomalous body, and synthetic inversion tests show a more promising imaging of geoelectric anomaly compared to traditional surface observation. We further extend this method to a set of field data in China, and the inversion results reveals two major concealed ore bodies below the current production surface with major geologic structures matching the geologic records. Overall, we verify the effectiveness of this method and algorithm and present that the ground-tunnel frequency-domain electromagnetic method is of research value in fields such as deep ore body detection especially in production mines.</p>