Surveys recently conducted in England, Ireland and Australia have shown that there are major spatial variations in the 'light' [molecular weight] hydrocarbon gas content of rocks which are closely related to the presence of underlying mineralisation. Light hydrocarbons are therefore regarded as a potential base metal pathfinder in mineral exploration, because they have a much broader distribution through the stratigraphy than do the base metals themselves. Four prospects in the central Flinders Ranges, South Australia, were selected by Mines and Energy South Australia (MESA) to test the reliability, reproduceability and logistical implications of using light hydrocarbons as pathfinders for hidden base metal deposits under Australian conditions. Three of the chosen prospects host known sub-economic Pb-Zn-Ag mineralisation. From MESA's work that is described herein, a definite spatial relationship between these mineralised prospects and anomalous levels of light hydrocarbons was established. One theory which explains the existence of this relationship in Australia's dry, deeply weathered crust is that methane and other light hydrocarbons, which are associated with primary mineralisation, are not permanently trapped within the interstices of the rocks grains, but are released at and from below the interface between the fresh rock and the oxidised/weathered rock zone. Methane and other C2-C5 hydrocarbons are able to migrate slowly via micropores and microfractures to the surface where they are released slowly over a long period of time. The fact that no one geophysical technique has proved effective in the discovery of carbonate hosted Pb-Zn mineralisation suggests that the use of light hydrocarbon haloes as an ore body detector is a potential exploration tool, when applied with detailed mapping. The most striking feature of the hydrocarbon technique is that in all deposits where the technique has been tested, both in Europe and Australia, anomalous levels of light hydrocarbons were detected close to known mineralisation.