Equipment Hazard Alert for Parking Brakes on Scoops
The Mine Safety and Health Administration recently issued a report saying that the Automatic Emergency Parking Brake (AEPB) on some Bucyrus (formerly Long Airdox) 400 & 600 series scoops may not automatically reset when the hand pump is used to release the AEPBs when the scoop is off. This could be associated with a number of issues, including component wear, or deviations from the original hydraulic circuit design. In such cases the AEPBs will be reset only when the scoop is re-energized and one of the hydraulic functions is operated.
Automatic functioning of AEPBs is required under Title 30CFR 75.523-3(b)(1) and (2). To insure compliance and correct operation, any 400 & 600 series scoops originally manufactured according to Bucyrus hydraulic schematics No. 220534, L-410181X20 or L-012334X1 must be maintained in accordance with Bucyrus hydraulic schematics No. 220534, L-410181X20, Revision “E”, and L-12344X1, Revision “D.” These revised schematics incorporate special notes which describe the potential issues with the AEPBs, and define the part number and installation procedure for a valve which will operate at very low pilot pressures. The following inspection can determine if a scoop’s AEPBs are in compliance:
- De-energize the scoop and block the wheels to prevent movement.
- Check that the AEPB pressure gage reads zero indicating the AEPB is set.
- Operate the hand pump to release the AEPB. The pressure gage will indicate pressure to show that the AEPB is released.
- Energize the scoop and allow the pump motor to run, but do not operate any hydraulic controls or apply the AEPB.
- To be in compliance, the pressure gage should drop to zero releasing the pressure, which indicates the AEPB is applied.
- If the AEPB pressure gage does not drop to zero to engage the AEPB, the scoop’s brake system needs to be brought into compliance. Operate a hydraulic function to release the pressure and apply the AEPB.
Please contact a field representative for assistance in correcting the noncompliance. The potential malfunction of the AEPB, however, may not be limited to this manufacturer only. www.msha.gov