Underground » Ventilation, Gas Drainage and Monitoring
This report describes recent research undertaken to develop, evaluate and calibrate a full-scale pressure test facility for ventilation control devices (VCDs) within Australia. It also examines a number of important aspects of stopping and seal performance, usage, design and application for the coal mining industry.
A review of the safety of coal mining operations after the Moura Number 2 Mine explosion resulted in changes to mining regulations in Queensland. Under the new regulations, ventilation control devices are required to be tested at "an internationally recognised mine testing explosion gallery" to achieve over pressure ratings of 14, 35, 70, 140 or 345 kPa.
There are a number of challenges for the industry arising from these changes. There was also a paucity of information on the appropriate selection and use of stopping and seals in mines. Compounding this was that until recently there was no prospect of the development of a full-scale test facility within Australia.
This research project examined the emerging responses to the changes in these regulations through an analysis of the results of a comprehensive survey of the operational context of the place of stoppings and seals in mines. Based on these survey results, coal mines across Australia have improved the quality of stoppings and seals installations in recent years in line with the actual or anticipated regulatory change. This research project also examined the current QLD regulations and compared them to the changing situation in some foreign countries with similar practices and mine layouts.
A study was undertaken to compare the TestSafe Explosions Gallery to the Lake Lynn Experimental Mine (LLEM). This was based on tests conducted upon one seal and one stopping. This comparison was enhanced through a combination of computational fluid dynamics simulations to model the methane/air explosions through time and space, and finite element analysis (to model the structure's response to the pressure impulse and measurements from full-scale tests.
The testing and structural analysis components of the project have shown that an Australian explosion test facility (TestSafe Explosions Gallery) can be used in the testing and approval of low pressure mine stoppings. They also outlined the nature of limitations to the use of the Gallery for testing high-pressure explosion resistant seals. Options for the verification of the explosion resistance of high-pressure seals are discussed.
The explosion modelling conducted on a range of possible alternative test configurations has recommended a simple test geometry rather than a simulated mine. At the time of writing this report, TestSafe is examining options for the construction of a new test facility for the verification of the ultimate explosion resistance of VCDs.
This report provides the basis upon which the mining industry, inspectorates and testing authorities can move toward the provision of innovative, safe and cost effective solutions for "approved" VCDs within Australian mines in the future.