According to internationally recognised ventilation expert associate professor Roy Moreby, the underground coal industry needs to acknowledge that achieving increased longwall production requires a different approach to ventilation practices as well as greater prestige for those who manage a mine’s ventilation.
Moreby predicts that the risk of ignoring this message will be less to safety, than to reaching scheduled production rates and achieving returns on investment.
Moreby is appointed to the staff of the School of Mining Engineering at the University of New South Wales (UNSW). Operating out of Plymouth, United Kingdom, he was in Australia in November to run the UNSW Ventilation Officers Course in Queensland. This is the first time the course has been presented in this state. Nine ventilation officers are enrolled in the Queensland course, run as three blocks of two week sessions.
Professors Jim Galvin and Roy Moreby developed the course in 1998 in response to strong pressure from Bruce McKensey, the then chief inspector in NSW, following explosions at Moura Colliery in Queensland and Endeavour Colliery in NSW.
Since then it has been adapted to the metalliferous sector and is in the process of being developed in a distant delivery format. In future, the course is to be administered through the National Centre for Mine Ventilation currently being established by the School of Mining Engineering at UNSW and will be available on an international basis
“Whilst the general standard of ventilation officers and people dealing with ventilation and gas drainage issues was generally good at the more demanding mines like the deeper mines on the NSW south coast, McKenzie recognised the need for an overall improvement in the knowledge and skills base of ventilation officers in the NSW coal industry,” Moreby said. This need was reinforced when the position of statutory ventilation officer was incorporated into NSW legislation in 1999.
The first course was run with 32 attendees in Newcastle in 1998. Of these, 10 dropped out during the duration of the program run over three days per month for 12 months whilst 16 have awarded certificates of competency to date. Moreby remembers an initial resistance from some attendees who thought they might be required to learn "rocket science".
“Halfway through they all changed and realised what was going on and how much better they could do things. Out of that first course they formed the Ventilation Officers Society of Australia and 46 people turned up to their second meeting recently.” The course is about to be run for the third time in the NSW coal sector.
A major milestone has been getting the course into Queensland last year. Capcoal (which runs the Bowen Basin German Creek operations) took the initiative in this regard and nine people attended the first course which is being very well received, according to Mitch Jakeman, general manager at Capcoal.
Moreby said the link between production and ventilation becomes increasingly important as mine production increases and the limits of gas management and spontaneous combustion are reached. What will generally kick in first is the cautious application of safety legislation: Gas levels unacceptably high = stop production.
“You might be planning a 165,000 tonne per week, 300m wide face at 6 kilometre long blocks,” Moreby said. “If your supporting systems can only get 110,000t/wk and go 5km tops you have to stop production to prevent going into a dangerous situation.
“I have, for example, people wanting to go to 6km blocks. You have to ask questions like what auxiliary fans are you trying to support at the end? And, do you realise if you go for short pillars, say 45m pillars over 6km - that’s somewhere in the order of 130 seals you’ve got to put in. On development they’re all going to leak. Can you support the fan at the end?
“In NSW where you still have 0.25% methane on entering a hazardous zone you can’t practically apply two-heading ventilation and maintain 0.25% on entry to hazardous zone. Therefore, you won’t achieve the block length you’ve designed and it comes back to project viability. If you don’t do anything different to current ventilation practice you won’t get there.”
But, as Moreby quipped, when you design a bridge you’re allowed to use something called "factor of safety", but with ventilation it’s called over-design.
In running the ventilation officers courses Moreby has noted a range in the levels of expertise: “In mines with problems with sponcom and gas drainage there were appropriate levels of skills. In other mines with fairly benign conditions gas-wise you had appropriate learning but when the mine wanted to put in a shaft or double production, the guy would be challenged in his ability to do that.”
Professor Roy Moreby will be contributing an article on ventilation practices and mine planning to the March 2001 edition of Australia’s Longwalls.