Air rotary drilling is used to drill deep boreholes in rock formations, and may be effective where other drilling methods fail. It’s one of the excavation techniques available to trenchless construction operators. Air rotary drilling may also be referred to as rotary air blast drilling.
The injection of high pressure compressed air is the key to the process of air rotary drilling. The air is injected into the drill pipe and flows to the drill bit. The injected air flow provides cooling for the equipment. It also brings cuttings back to the surface and helps to maintain borehole integrity. Air rotary drilling has historically been used in bedrock formations. It is considered environmentally friendly, and offers cleaner samples from the borehole compared to other methods.