Holes drilled in development(jumbo rounds) or production (longhole drills) are done drilling dry. Dust collectors are mounted on the drill units. Cups are located at the end of the boom to capture the dust at the collar of the hole. If the cup doesn't sit properly ( face is very rough ) it can become very dusty. The only exception is in the diamond drilling, where a calcium chloride solution at about 22% strength is utilized in order to keep the drill string from freezing up. This is due to the length of the hole also that goes beyond the normal production hole lengths by a considerable amount. A tub is used to recycle the solution and solution exiting the hole is captured in a sump on the ground and returned to the tub. This is my experience at one mine in the Canadian high arctic.
