E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
E21B21/16—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor using gaseous fluids
E—FIXED CONSTRUCTIONS
E21—EARTH OR ROCK DRILLING; MINING
E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
E21B21/01—Arrangements for handling drilling fluids or cuttings outside the borehole, e.g. mud boxes
E21B21/011—Dust eliminating or dust removing while drilling
E21B21/012—Dust eliminating or dust removing while drilling using exhaust air from the drilling motor for blowing off the dust at the borehole entrance