Document Type

Conference Paper

Publication Date


Publication Details

Y. Ma, D. Bringemeier, A. Scheuermann, T. Molebatsi & L. Li, Fault and fracture zone detection based on soil gas mapping and gamma ray survey at the extension site of an open pit coal mine, 12th Coal Operators' Conference, University of Wollongong & The Australasian Institute of Mining and Metallurgy, 2012, 378-386.


Identification of open active faults and fracture zones is a part of exploration study prior to mining operation. However, detailed mapping of geological discontinuities in an otherwise low permeable overburden is rarely carried out in the mining area. To develop a rapid and feasible survey method, a field campaign was conducted to examine different soil gas survey methods along three transects at the Carrington West Wing extension site of a coal mine, Hunter River Valley, NSW, Australia. Coal seam gas together with Uranium-238 (present in the gas-bearing coal seam) increases the soil gas signal which can be detected with suitable soil gas mapping methods. Three techniques associated with four parameters were tested at the field site. A conventional active soil gas sampling method was applied with the samples analysed off-site in the lab by gas chromatography for carbon dioxide and methane concentrations. Radon was measured on site by means of radon detector. It was expected that high soil gas concentration anomalies, if detected, could then be related to the locations of permeable fault/ fracture zones. A rapid and simple technique was used to determine the relative counts of Bismuth-214 in the soil surface by employing a gamma ray spectrometer. As a decay product of the 222Rn, 214Bi is also expected to exhibit relatively higher activities in the soil over faults and fracture zones.