The automatic emergency-parking brakes on some Bucyrus 848 Un-A-Haulers may take 4 to 5 seconds to activate after the panic bar is hit, according to a safety alert from the Mine Safety and Health Administration. When this type of equipment is field tested, the brake must engage within one second after hitting the panic bar. As a precaution, the 848 Un-A-Haulers should be field tested to determine if the brakes activate immediately (within one second) when the panic bar is hit as required by 30 CFR 75.523-3(b)(1).

Bucyrus has issued a bulletin describing a remedy for the delayed brake activation, which consists of replacing the brake solenoid valve with a replacement solenoid valve and a pilot-to-close check valve. For more information, go to ^{[1] [1]}. Contact a Bucyrus representative with any questions.