Using the smaller Wassara hammer sizes, W50, W70 and W80, is the best solution since the lengths of the hammer and the drill tube could be kept optimal. The handling of the out-coming water is usually not a problem; 80-130 liters/min (new hammer), or, 105-195 liters/min (semi-worn). The smaller hammers also mean smaller equipment and smaller pumps. The pump can, with preference, be placed hundreds of meters away from the drill rig. The fact of dust-free air in the gallery is also one great environmental advantage.