1. Keller Group Global D-Wall Workshop Equipment selection

2. D-wall equipment selection  D-wall excavation equipment types: o Mechanical clamshell. o Hydraulic clamshell:  Free hanging.  Partial or full Kelly attachment. o Hydromill / Hydrofraise / Cutter

3. D-wall equipment selection  Free hanging cables operated mechanical clamshell: o Round or square jaws, depending upon type of end-stops system used. o Upper body frame used as guide to ensure vertical excavation. o Upper body frame weight will dictate capability of excavating dense soils. o Operator skills and experience are critical with this bucket type to control its swinging and guarantee vertical excavation. o Can be equipped with gyroscope type device for verticality control,

4. D-wall equipment selection  Free hanging cables operated mechanical clamshell: Low headroom clamshell

5. D-wall equipment selection  Hydraulic clamshell: o Free-hanging or attached to a Kelly-bar frame. o Round or square jaws, depending upon type of end- stops system used. o Kelly-bar frame will ease control and insertion of bucket into the guide-walls. o Kelly-bar frame will limit excavation capabilities into dense and hard soils. o Free-hanging hydraulic clamshell similar to mechanical bucket, but extremely powerful in dense soils (when not supported on full length Kelly). o Can be equipped with gyroscope type device for verticality control. o Operator “friendly” tools.

6. D-wall equipment selection  Hydraulic clamshell: Cable suspended Cable suspended & telescopic Kelly for GW ease of insertion and guidance

7. D-wall equipment selection  Hydraulic clamshell: Full length Kelly grabTelescopic Kelly grab

8. D-wall equipment selection  Hydromill / Hydrofraise / Cutter: o Reverse circulation rig. o Cut soils and rock into 3” size particles which are pumped with the drilling fluid and send to a large capacity desanding plant. o Desanding plant will separate the spoils from the drilling fluid and return the cleaned fluid to the excavation trench. o Will excavate into hard rock. o Equipment can be controlled and monitored in real-time as excavation progresses to great accuracy. o Can be used to great depth.

9. D-wall equipment selection  Hydromill / Hydrofraise / Cutter:

10. D-wall equipment selection  Hydromill / Hydrofraise / Cutter:

11. D-wall equipment selection  Hydromill / Hydrofraise / Cutter: Soilmec’s 250 m deep hydromill test

12. D-wall equipment selection  Hydromill / Hydrofraise / Cutter:

13. D-wall equipment selection  Hydromill / Hydrofraise / Cutter:

14. D-wall equipment selection  Bucket excavation monitoring: o Gyroscope / Inclinometer in bucket. o Records bucket path during excavation. o When bucket is out of panel, data sent to on- board computer for visual information to operator. o Some grabs are equipped with real-time monitoring and action on side flaps allows for verticality correction. o Use of Koden sonar caliper during and / or after excavation completion is recommended to final verification.

15. D-wall equipment selection  Bucket excavation monitoring:

16. D-wall equipment selection  Hydromill excavation monitoring: o Gyroscope / Inclinometer in hydromill body. o Records path during excavation and information is displayed real-time to the operator who can “steer” the hydromill and correct its path. o Use of Koden sonar caliper during and / or after excavation completion is recommended to final verification.

17. D-wall equipment selection  Hydromill excavation monitoring:

18. D-wall equipment selection  Koden sonar caliper verification:

19. D-wall equipment selection  Proposed selection guidelines: Equipment typeSoils Verticailty tolerance % BedrockDepth in m (ft) ClamshellAny0.5 to 1.0Weak / Weathered110 (330) Clamshell + Chisel-Medium110 (330) Kelly Grab soft to medium dense 0.5No55 (180) Hydraulic Clamshell Medium to very dense 0.5Medium70 (230) HydromillAny*< 0.5Hard to very hard 150 - 250 (490 - 820) * Performance in clay is limited and requires specific cutting wheels