Twin Rotary Drive Drilling System for large diameters

• A long outer casing and an inner continuous flight auger are drilled into the ground simultaneously by two rotary drives rotating in opposite directions, assisted by the crowd force of the crowd winch system.
• Concrete is placed through hollow stem auger as drill casing and auger are simultaneously withdrawn.
• The system is used for constructing bored piles and secant pile walls.
• Technique can be employed in all types of soil without rock formations and boulders. 
• Diameters 600 - 1200 mm
• Drilling depth 12-20 m