There is a time factor associated with the agglomeration process. Dust particles must collide with water droplets several times to grow large enough to settle or attach to a surface and collisions are a matter of probability through time. Containment systems, then, must be of adequate size to provide the retention time required for adequate collection.
The enclosures associated with fog systems are generally larger than conventional enclosure used with dust extraction or simply to contain the flow of ore on a conveyor. Retention time is the principal that dictates the need for those larger enclosures.