The Drilling diameter vs. ...

The Drilling diameter vs. drill-pipe size is probably too big  to get the cuttings lifted. Try to inject water (I hope you did already for cooling & lubricating your hammer and the bit while drilling) and add any kind of foam additives you can find on the market (even OMO or whatever kind of washing powder is allowed) and add it into the water, which you inject into the airline...make sure you get a slope somewhere, secure any kind of holes and pits by marking them and lift all tools from the ground, because you'll create a foam-tarpet and it can become dangerous for your colleagues. It is, of cause, an environmental impact if you are in sensitive areas like lake, river or food supply-farming. The other option is to get biodegradable products or just a stronger compressor with more air volume min. 300 lit/sec @ 12 bar.

If you want to know more about, please let me know.

Good luck.

Ulf