Underground » Health and Safety
Simtars under the auspices of the Queensland Mines Rescue Service (QMRS) and ACARP has been investigating the operation of underground coal mine personnel transport vehicles in non standard mine atmospheres.
This report describes the performance testing of a number of flameproof diesel engines currently in use in personnel transport vehicles in Queensland and NSW underground coal mines in high levels of methane.
The results of this testing showed that flameproof diesel engines are quite capable of operating safely in methane concentrations well into the explosive range. While they have been found to have the potential to develop significantly more power under these circumstances they can be operated so as to perform similarly to a vehicle driven in normal air.
To be able to show this in a more practical fashion a demonstration was performed which involved the testing of a complete vehicle under conditions simulating those which could be encountered in exiting an underground coal mine.
The demonstration viewed by a number of Mining Industry representatives proved successful as it showed that a vehicle suddenly encountering high methane concentrations would have more power available to it, but that this extra power could be easily controlled by reducing pedal effort. While the engine may exhibit very high idling revs due to the presence of methane it was still possible to drive the vehicle as slow as 3 to 4km/hr in first gear without having to ride the brakes.
The observation is that while ever the vehicle is only asked to perform as it would normally, regardless of the methane concentration present, (i.e. the extra power was not exploited) engine temperatures should remain similar to that for the vehicle driven in normal air.