To achieve certification candidates must take the Drill Rig Operator Core written exam and at least one written specialty exam (Foundation Drill Rig and/or Anchor/Micropile Drill Rig), as well as the corresponding specialty practical exam.
[pdf] Search for U.S. oil and gas operators by operator name or browse by county to find the operator you're looking for. Find wells by operator, the oil and gas produced by county per operator, and recent drilling permits filed by U.S. operators. Want even more details on U.S. oil and gas operators?
[pdf] 
A down-the-hole drill, usually called DTH by most professionals, is basically a jackhammer screwed on the bottom of a drill string. The fast hammer action breaks hard rock into small cuttings and dust that are evacuated by a fluid (air, water or drilling mud). The DTH hammer is one of the fastest ways to drill hard rock. The system is thought to have been invented independently by Stenuick. Origin of the nameDTH is short for “down-the-hole”. Since the DTH method was originally developed to drill large-diameter holes downwards in surface-drilling applications, its name originated from the fact that the percussion mechanis. .
In DTH drilling, the percussion mechanism – commonly called the hammer – is located directly above the drill bit. The drill pipes transmit the necessary feed force and rotation to the hammer and the bit, along with the flui. .
A is first thought to have been used for rock drilling in 1844. Many quarries used hand held tools that required the driller to suspend himself from a rope over the quarry face in order to place the drill hole in.
[pdf] 
