Pennsylvania Statutes Title 52 P.S. Mines and Mining § 70-253. Props or timbers supporting roof not to be removed by cutting, removed by blasting or prop puller

No person or persons working in any coal mine or colliery shall cut any props or timbers while the same are in position to support the roof or sides. When it becomes necessary to remove any of the said props or timbers they shall be removed by blasting or by means of a prop puller. Such prop puller, however, shall be designed and constructed with ropes or chains of sufficient length that the person operating the device will not be exposed to the danger of a falling roof or falling coal resulting from the removal of such props and timbers.