IDPO-IDDO is in the process of upgrading the 4-Inch Drill design. The upgraded drill design is referred to as the Foro Drill ('Foro' is Latin for "to bore, make a hole"), and the design of its sonde, winch, and tower reflects beneficial aspects of the Intermediate Depth Drill (IDD) design while offering generous weight savings whenever possible. In addition, the new sonde design will also be submersible and watertight. It is important to note that the two existing 4-Inch Drill systems will remain in IDDO's inventory of drills available for community use.
Below is a list of major specifications and design features of the Foro Drill, along with some comparisons to the existing 4-Inch Drill system.
System in development; fabrication of the new Foro Drill components during PY2016
The sonde design is based on the IDD design and shares most of the same anti-torque and motor section components. The main difference is the core barrel. The IDD drill has a dedicated chips chamber located after the motor section followed by the core barrel. The Foro Drill shares the same core barrel design as the 4-Inch Drill, where the cuttings are collected above the core inside the core barrel. This is a simpler design and better suited for removing the core barrel from the drill vertically, like the 4-Inch Drill currently does. The Foro Drill will be compatible with IDD chips chamber and core barrel assemblies.
Major Drill Specifications
- Total length - 3.8m long (same as the 4-Inch Drill)
- 98mm diameter core (the 4-inch Drill has a 104mm - 107mm diameter core)
- Designed to recover 1m long core (same as the 4-Inch Drill)
- Total drill weight will be ~64kg
- Sealed motor section - submersible in drilling fluid or water; pressure rated to 4,000 meters in drilling fluid; the 4-Inch Drill is not submersible
- Capable of running reamers - 178mm and 229mm in diameter reamers, currently built for IDD, will work with this drill
- Most components are interchangeable with the IDD Drill
Winch & Tower
- 5.7 mm diameter steel electromechanical winch cable, same as used on the IDD Drill; the current 4-Inch Drill cable is 13mm in diameter
- Weight is 13.1kg/100m; the current 4-Inch Drill cable weight is 17.1kg/100m
- Winch drum will be ~75mm smaller in diameter and ~ 60mm narrower than the existing 4-Inch Drill winch drum
- Winch and tower base will have a sled design with tow points on either end
- Winch drum will be removable
- Tower design planned to be similar to the existing 4-Inch Drill design, utilizing fiberglass tubing
- Winch motor will have a built-in fail safe parking break that is automatically set when the winch is stopped
- Top sheave, instrumented to read cable payout and tension
- Drill and winch motors will be able to be run simultaneously
- Off-the-shelf motor controllers
- Fine low speed control for the winch motor, so it can be used for coring operations (cable payout on the 4-Inch Drill is controlled by the operator applying friction to a hand wheel with their glove)
- Analog current meter for the drill motor
- Off-the-shelf line control meter for monitoring cable payout, cable speed, and cable tension (the same LCI-90i meter as used on the Intermediate Depth Logging winch and IDD systems)
- Reduced weight, compared to the existing 4-Inch Drill control boxes
- With the new Foro Drill, the expected ice core quality, including the firn core (from the air-snow surface down), is expected to be at least equivalent to the quality of cores produced by the existing 4-Inch Drill.