Marginal analysis, forsooth!
The last of its breed, Silver Spade carried on alone until April 19 when it suffered a serious breakdown. Nineteen of 100 rollers fell out of place between the shovel's stationary bottom and its revolving top, resulting in the shovel's demise.
The rollers weigh about 800 pounds each and are the size of a quarter keg of beer. Replacing them would be a big, expensive job, said Kent Henschen, Bucyrus marketing manager.
At some point, it's not worth the money to rebuild old machines when the new technology is better, he said.
YOU SHOVEL 15,000 TONS AND WHAT DO YOU GET? If you're the last operating giant stripping shovel, honorable retirement in a mining museum to be established right where you broke down.