During drilling of the surface hole (12 ¼“), the driller made a connection and started to wash / ream down to bottom. Due to tight hole conditions, the drill string stopped two feet before the bushings were able to be set into the rotary table. The driller received direct instructions from the company representative to operate the kelly spinner to over come the tight hole and the drill string did move down for ½ foot. The driller was re-instructed by the company representative to move the string up and down. During the process of moving the string down, the drill string reached a bridge, but the driller didn’t notice it. This resulted in the string bouncing and the swivel hitting the hook, causing the latch to open and the kelly to drop to the rig floor resulting in damages to Kelly, rig floor handrail, mast ladder and driller’s panel.