Geophysical surveys conducted in order to map tunnels and vertical shafts at the Neolithic chert mining field Krzemionki used a ground-penetrating radar (GPR) to test hypotheses regarding orientation, depth and subsurface complexity of these voids. Using two-dimensional reflection profiles the vertical shafts, now mostly filled with lithic debris, were easily visible. Amplitude mapping visualized debris at shaft margins as well as a collapsed material inside the voids. Some shallower horizontal tunnels were also visible as sub-horizontal planar reflections generated from both ceiling and floors of these void spaces. Extension of these interpretations to un-mapped areas of the ancient mining district and complexity of these prehistoric mining features could be examined to determine excavation intensity and exploitation techniques used during the Neolithic.