Keene 151 - Gold Nugget Hunting & Prospecting Forum - Rob's …
Air speed needs to be fast. Speed up to an estimated air speed of about 170 MPH. The velocity needs to. be enough so the blower and motor tends to want to move (vibrate) about, and may need to be braced to stay still (put). Also the dirt needs to be dry to develop a static charge. This is true with a hot.