UMW representatives suggested banning the practice during testimony before a Mine Safety and Health Administration panel Tuesday in Charleston.
But if the practice is allowed, union representatives suggested safety improvements such as requiring approval of belt air usage by MSHA's director, not regional executives.
Besides allowing belt air, MSHA wants to require flame-resistant belts and carbon monoxide detectors instead of heat-sensing fire alarms, among other things.
The rules are required by federal legislation adopted after high-profile accidents in 2006, including a belt fire that killed two miners in West Virginia.