Although the mine had an array of dust control methods -- the shearer had advanced dust suppression systems including shearer clearer air curtains and sprays, and the maingate drive and bulk stage loader contained an assortment of sprays and dust suppression systems -- the AFC had no form of dust control.
Coal cut at the shearer could travel up to 240m along the AFC to reach the maingate drive and BSL, and the ventilation velocities along the face easily picked up small dust particles, contributing to the overall dust hazard.
Creative longwall operators, including Wade “Flipper” McDonald, came up with an idea to install adjustable fire nozzle sprays along the AFC, approximately every 30 chocks. The spray system was designed to efficiently dampen the coal flowing along the AFC to reduce dust being picked up by the ventilation system.
Brackets were manufactured and the system installed at a minimal cost of approximately $100 per bracket and $43 per nozzle.
During production the face operators turn the sprays on to wet the coal along the AFC. As the shearer approaches, the sprays are turned off and moved to avoid damage from the shearer as it cuts to the maingate. When the shearer flits to the tailgate, the sprays are turned back on as the shearer passes. This means the sprays are only on when there is coal on the AFC.
Southern colliery submitted the idea to the Innovation Awards which are part of the Queensland Mining Industry Health and Safety Conference.
“This innovation has provided Southern Colliery with a simple, effective means of reducing dust generated from the coal on the AFC,” read the mine’s submission.
“It is difficult to discriminate the sources of dust to solely quantify the benefit from these AFC sprays. Regardless, this spray system is aimed at benefiting all longwall face operators at the mine. From observation, it appears to be effective.” Published in Australia’s Longwalls, September edition