Mist drilling is a name given to what technique in air rotary drilling?

• A. A technique using a mix of air and small amounts of water or foam to cool the bit and lift cuttings
• B. A method using only water for cooling
• C. A technique that uses mud as primary fluid
• D. A method to reduce noise levels

Answer: (A)

Mist drilling centers on flowing a light mist of water or foam along with the air in the air rotary system. That tiny amount of liquid cools the drill bit and helps the cuttings stay suspended and be carried upward by the airstream to the surface. It’s this combination—air as the lifting medium with a small amount of liquid for cooling and cutting transport—that defines the technique. It’s not about using drilling mud, nor just cooling with water alone, and reducing noise isn’t the primary purpose.