This is called a roller bit, Its usually put on oil rigs or tunnelers.they work extremely well when it comes to breaking rock or dirtSo what they are doing is essentially calibrating and unjammingthe roller bit so it can function properly

This is a drilling bit for drilling wells. It is technically an insert tri-cone bit. Often referred to as a roller cone bit, or simply a rock bit. The parts sticking out are inserted into the cone and they crush rock as the drilling assembly is rotated. There are several types of tri-cone bits. There are other types of bits that are not tri-cone. (ie., PDC bits, hybrid bits, and more.
As far as what they are doing, l’d have to say that they are just inspecting the bit. Seeing if the cutters on the cone and the bearings for the cone are in good enough shape to run it down hole again.