Under Consideration - Possible Future Development
In response to community need for a scalable modular hot water access drill in the Long Range Science Plan, IDDO has started work on a Scalable Hot Water Drill (ScHWD) for the community. This drill will be useful for investigating sub-ice shelf mass balance, ice-ocean interactions, grounding zone processes, and other studies. Mary Albert worked with science community representatives Sarah Das, Dave Holland, and Ted Scambos, and with Chris Gibson, IDDO project manager and engineer and Terry Benson, a University of Wisconsin Engineer with hot water drill experience, through an iterative process to define the science requirements for a hot water drill whose size could be scaled to project needs.
The following are the final approved science requirements for the drill that have been defined through virtual discussions organized by IDPO in December 2013, and follow‐up teleconferences and discussions with the research community and with IDDO staff.
- Produce access holes through ice depths between approximately 50 – 1000 m.
- The drill should be modular, with built‐in redundancy, so that one of the modules is used for shallow depths and small diameter holes, and other modules are added for deeper access holes or for larger diameter holes.
- Diameter of holes needed will vary, with most likely in the 10‐30 cm diameter. Small diameter holes can be drilled deeper than large diameter holes (e.g. 10 cm diameter hole could be drilled to 1000 m in 35 hours, while a 30 cm diameter hole could be drilled to 600 m in 35 hours of drilling, for example).
- Drill should be operable in borehole and/or ambient temperatures down to ‐30 C.
- The drill should be agile on site, in order to drill multiple holes within 500 m of emplacement, possibly moved around by skidoos.
- Setup time for the drill on site should be within 48 hours.
- The design should include the ability to maintain a 30 cm diameter, 600 m deep hole and keep it open for 8 hours after initial drilling.
- The drill should be able to be transported by helicopter sling load, Twin Otter, Basler or light ground traverse.
- The drill should have stand‐alone capability for operation at small field camps at remote sites
- Minimal staff (4 pax for setup, working 2 per shift for drilling and reaming) should be required for drilling operations in the field; other field camp staff in support of drilling operations to be provided separately
- Drilling depth and rate of drilling progress should be recorded.
- The design does not require "clean" access for most applications, but the drill should be designed and constructed with fittings and components that will facilitate adapting the system to "clean" drilling in the future.
- The design does not require operation to depths beyond 1,000 m for a 10 cm diameter hole, but to allow for future expansion of the system, the hoses and fittings shall be suitable for the operating pressures required to achieve a 1,500 m, 10 cm diameter hole.
While the existing Small Hot Water Drill will be refurbished and maintained for holes to 60m, the ScHWD will be capable of supporting a wide range of science from shallow access holes for basic measurements to 1000m deep holes accessing the ice‐bed interface. To achieve this, the ScHWD will rely on modularity, using compatible modules to allow the expansion or reduction of the system to better fit the needs of a specific field project. Because this drill will be operated in very remote locations the design of the drill will focus on safety and logistical costs.
The drill will have some inherent flexibility allowing, for example, a deeper depth for a longer drilling time or smaller diameter hole; for example if the drilling time is extended to 40 hours, a 30 cm hole could be drilled to 700m. The amount of energy needed for depths beyond 1,000 m and energy above 600 kW would require a larger hose diameter and/or a bigger high‐pressure pump, which is counter to the intent of an agile modular drill.
The conceptual design of the ScHWD is nearly complete: an internal review of the drill concept was conducted in mid-May 2014, and an outside review of the drill concept was conducted in late June 2014.
Conceptual layouts illustrating what the smallest and largest ScHWD system configurations in the field may look like. A Twin Otter is shown for reference.
Questions or comments should be sent to Mary Albert.