At the time of the incident, the driller was working the drill string and was about to
make a connection. He heard a noise coming from the drawworks; the rig manager was in the doghouse and went to investigate the noise. He noticed that the retainer bolt for
the dog nut anchor plate on the TSM 7000 drawworks had backed out. Eventually, the bolt was out far enough that it produced friction on the drilling line
causing two of the six strands to break