A Tier 3 method to estimate fugitive gas emissions from surface coal mining

► A Tier 3 model for estimating gas emissions from surface coal mining was developed. ► 'Gas release zone', 'emission layer' and 'gas reservoir' concepts were developed. ► These concepts were applied to gas bearing strata in surface mining. ► The new model was applied to an active surface mine in Australia. ► Cost is reduced using 'gas zone' concept: area of similar gas content/composition.