Methane explosions in gold mines have been attributed to spontaneous ignition of methane/air mixtures. Biogenesis of methane in the heartwood of diseased trees has been shown, but never in timber in service. Studies were therefore undertaken to establish whether methanogens were present in wooden pit props. Core samples were removed by Pressler increment borer from props in disused areas 2,600 m deep in a gold mine, using strict anaerobic techniques. Samples were milled, homogenised, diluted and used to inoculate methanogen enrichment broth containing radiolabelled NaH14-CO3 in Wolfe tubes pressurised under an 80% H2 / 20% CO2 atmosphere. They were incubated at 38°C for 12 weeks, with intermittent repressurisation. After separation by GLC, headspace 14CO2 / 14CH4 proportions were measured using a 14C detector on a gas proportional counter and methanogenesis rates were calculated. The presence of methanogens in pit props was unequivocally confirmed. Present work investigates the characterisation and identification of these methanogens.

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