US2573535A - Coal handling system - Google Patents
US2573535A US645864A US64586446A US2573535A US 2573535 A US2573535 A US 2573535A US 645864 A US645864 A US 645864A US 64586446 A US64586446 A US 64586446A US 2573535 A US2573535 A US 2573535A Authority US United States Prior art keywords coal chute hopper storage feeding Prior art date Legal status (The legal …