Heavy pulling and jarring shall be carried out using the top drive/ kelly on the string. On those rare occasions where this is not possible, the elevator latch shall be secured by means of a rope or chain. Remove the kelly spinner (if possible) before any jarring with the kelly is done, to avoid damage.
When sustained jarring is done, the block-line shall be slipped at regular intervals to avoid permanent damage to the line at the cross-over points. The time interval between slipping depends on the intensity of the jarring.