Underground » Ventilation, Gas Drainage and Monitoring
Lunagas was asked to perform a professional data and results analysis regarding gas emission phenomenon for sealed goaves and abandoned coal mines in Australia. Consequently, historical data and results for the period 1985 - 2004 were used to establish the most typical curves, which define the relationship between coal mine gas emission decline rates and time. The curves represent gas emission rate changes with time, under various geological, mining and gassy conditions. Coal mine gas emissions declining with time phenomenon, presented in this report being considered for dry mine case only, assuming that the equilibrium between the quantity of gas released from the strata and recovered from underground workings (captured plus vented) vary with time and is related to local gassy, geological, mining and atmospheric conditions.
The object of this analysis is to define an initial standardized procedure for estimating abandoned coal mine emissions and to apply this procedure to abandoned mines in Australia. Equation sets and methodologies discussed in this report provide an initial framework for predicting long-term methane emission rates. This work was combined with a field program that measured methane emissions from selected coal mines located in NSW and QLD. Based on the results of the field program, the approach outlined in this report should be modified or changed, to reflect specific local conditions, which may vary from those studied in the report. For this report the existing data has been updated with new and current results from Teralba, West Wallsend, Appin, Cordeaux and Central Colliery as well as other coal mines in Australia, Poland and the USA. The data and results have been selected, classified, computed and analysed to fulfil the established ‘Work Plan’.
This report is an initial step in a process that is expected to evolve as new data and information is collected and incorporated into the abandoned mines methane emission estimates. The continuation of that study, including the flooding water component will be carried out in the subsequent ACARP report No.C14080 titled Australian Decommissioned Mines Gas Prediction by Lunagas and Wardell Armstrong.