SOUTH MILWAUKEE, Wisconsin BUCYRUS INTERNATIONAL has sold the first large dragline of any make to China. The model 8750 with a 90-m bucket is going to the Zhungeer mine belonging to the SHENHUA GROUP. This is also the first dragline to be entirely powered by a Siemens AC static drive system with a direct (gearless) drive system for the hoist and drag motions.
Direct drives have been around for many years in a variety of mining and milling applications, but Bucyrus may be the first to apply it to draglines. New machines can be ordered with what Bucyrus calls D (direct drive for draglines) technology, or it can be retrofitted to existing machines. An advantage of direct drive in this instance is that when the conventional hoist and drag motors are removed, the expensive lubrication equipment needed to maintain and prolong gear life is no longer needed, either.
Bucyrus says that dragline operating improvements with D may be as high as 20%, although specific gains are dependent on individual installations. The bottom line is that overburden removal costs are lowered. More information is available at www.bucyrus.com.