You do a disservice to your arguments by incorporating nonsense statements within them. Remarks such as these undermine any confidence in the rest of the post.
- Drill bits do not "melt in 5 hours".
- Drill bits do not melt.
- It does not take ten days to complete a round trip (unless you've selected a rig whose hoisting apparatus is powered by donkeys, or have used some other inefficient, unconventional approach).
Drill bits may suffer various forms of wear and damage. The closest that one comes to melting would be thermal cracking of the surface of the steel bit body, but this is primarily a consequence of frictional heating. Frictional heating is also a major factor in failure of the bit cutting structure, whether of tungsten carbide inserts on old-style roller cone bits, or diamond layer of PDC cutters on modern bits. However thermal degradation of the diamond layer is quite different from melting.