Crane Rental Corporation recently recovered a customer’s Manitowoc 4600 dragline that had slipped off a bank below 70 feet of water at maximum radius off the shore (no one was injured during the accident). CRC supplied a lift director, skilled riggers, certified crane operators, and cranes to perform the coordinated tandem lift. The machine was recovered with Crane Rental Corporation’s Manitowoc 2250 crawler crane with MAX-ER attachment (500-ton capacity) and Terex AC 500-2 hydraulic truck crane (600-ton capacity). The total weight lifted was approximately 484,000 pounds.
Crane Rental Corporation had to prepare pre-lift plans and submit them to the Mining Safety and Health Administration (MSHA) for approval before beginning the job. CRC has performed nearly a dozen recoveries after similar unfortunate accidents.
During the job professional divers surveyed the machine. Engineers had to assess and predict the components’ stored energy before divers cut the boom, mast, and heavy-duty wire rope under water to ensure the divers would not be struck as components shifted. Underwater cameras and communications were essential as the divers’ exposure needed to be limited at that depth. The project was completed safely with zero recordable incidents.