Although there is a wealth of information on the emission of gas and explosions due to methane-air and/or coal dust in mines underground, the underlying threats on the surface from the explosive energy transmitted through the mine entrances have been largely overlooked. These hazards have the potential to cause injuries and loss of life. Additionally, they can lead to severe damage to the surface infrastructure surrounding the mine entrance. This study aims to establish the relationship between characteristics of blast waves emanating from the mine entries for different magnitudes of explosions and radial distances. An Advanced Blast Simulator (shock tube) was used to experimentally study the propagation of blast waves from mine entrances and over an outside mine site terrain (for mine portals) or upwards towards the sky (for mine shafts). Computational Fluid Dynamics modelling was utilised to interpret the experimental data, verify the applicability and scalability of the small-scale
A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive events. Shock tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance range. Some wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications, inadvertently cause flow anomalies, and/or are only applicable under very specific configurations. This paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube facilities. The use of controlled venting is demonstrated experimentally using the Advanced Blast Simulator (shock tube) at the Australian National Facility of Physical Blast Simulation and
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The risk of explosions in coal mines is an important subject that requires a comprehensive understanding of explosion dynamics, mining operations, and mining safety. A high level of knowledge is now available in the field of gas emissions, gas, and coal dust explosions in underground mines. However, not sufficient attention has been given to the potential risks associated with explosive forces expelled through the mine opening and resulting in injuries and fatalities to personnel (underground and at the mine portal) and catastrophic infrastructure damage in proximity to the mine opening on the surface. This paper presents a methodology for predicting explosion risk around the coal mine openings (drifts, shafts, boreholes, etc). The proposed methodology is based on establishing an empirical relationship between the parameters of blast overpressure waves emitting from mine entries and the radial distance at an azimuth angle for the various magnitude of methane or coal dust explosions. An
The current state of blast resistant design methods is largely reliant on empirical observations of field explosive testing or numerical simulations. While both methods are undoubtedly vital and necessary, they both have inherent limitations. Field trials for performing systematic experimental studies are exceedingly expensive, produce inconsistent results, and are slow in the rate of testing. Conventional blast simulators (shock tubes) enable blast testing to be performed in a safe and controlled laboratory environment but usually do not correctly replicate free-field blast conditions which could lead to deceptive outcomes in regard to target loading and response. The National Facility of Physical Blast Simulation (NFPBS), based on the ‘Advanced Blast Simulator’ (ABS) concept, was established at the University of Wollongong to overcome the shortcomings of conventional blast simulators. This simulator intrinsically replicates the wavedynamics of free-field explosive blast and is un