
H&B Mining – Hard Skirts Case Study
BySkirt liners dropping onto conveyor belts cause significant downtime and lost production. Dropping is caused by selfloosening in the liner fasteners. This occurs when the tension (stretch) in the bolt is insufficient to prevent slip within the joint from high vibration/impacts. The uncontrolled torque from impact wrenches (rattle guns) cannot consistently develop the required bolt tension.
The current industry mitigation method is the use of a nyloc nut on each liner bolt. Although this prevents the nut from falling off the bolt, it does not maintain the tension in the bolt. As such, if the nut is not sufficiently tightened, rotational loosening will occur until the bolt relaxes and the liner is no longer clamped to the skirt panel.
