26/05/2015 · Underwater Drill, Blast Dredge Rock Step 1 Equip Spud Barge Step 2 Install Casing to Rock Step 3 Drill 65 mm dia blastholes Step 4 Install Ducts Remove Casing Resources : Crawler Crane 30 tonne capacity Top of duct to be above high tide level. Step 5 Charge Holes from Work Boat Step 6 Move Barge away from Blast Step 7 Blast Rock Step 8 .