Developing a hot-water drill system for the WISSARD project: 3. Instrumentation and control systems

Abstract

ABSTRACT. The WISSARD (Whillans Ice Stream Subglacial Access Research Drilling) traversable hotwater drill system was designed to create various-diameter ice boreholes to a depth of >800 m, with most major components being controllable from a single user interface. The drill control system operates four low-pressure pumps for water generation and circulation, two hot-water generation units containing a total of six diesel burner modules with integrated high-pressure pumps, three winches (one with independent level-wind motor), a four-motor linear traction drive, and a large number of analog and digital sensors to monitor system performance and cleanliness. Due to development time constraints the control system design focused on utilizing commercial off-the-shelf components, while being highly modular, easily expandable and rapidly deployable. Additional emphasis was placed on providing redundant manual operator controls and maintaining a low degree of system automation to avoid dependence on software control loops for first-season deployment. The result of this design paradigm was a control system that was taken from concept to full operation in <6 months, successfully performing in the field without insurmountable problems.

Biogeochemical Connectivity Between Freshwater Ecosystems beneath the West Antarctic Ice Sheet and the Sub‐Ice Marine Environment

“…SLW water and sediments were collected through a ~0.6 m diameter borehole that was created with a microbiologically clean, hot water drilling system (Blythe et al, ; Burnett et al, ; Priscu et al, ; Rack et al, ; Tulaczyk et al, ). Lake water samples were collected with a clean 10 L Niskin bottle and sediments were recovered using a clean gravity multicorer (Uwitec).…”

Biogeochemistry and microbial diversity in the marine cavity beneath the McMurdo Ice Shelf, Antarctica

“…At the time of sampling, the transition from sea‐ice to the open water of McMurdo Sound was approximately 48 km to the north of the sampling site. The 56 m deep borehole (∼ 60 cm diameter) that penetrated into the sub‐ice shelf cavity was created with a clean access hot water drill (Blythe et al ; Burnett et al ; Rack et al ) on 18 December 2012. The sub‐ice shelf cavity is defined as the ocean beneath the ice‐shelf.…”

Clean subglacial access: prospects for future deep hot-water drilling

“…Reelers can be powered either hydraulically or electrically and although hydraulic systems can be used to prevent problems with electrical noise, some implementations have suffered from problems with large temperature fluctuations adversely affecting fluid viscosity, low torque at slow speeds and poor positional accuracy, though these features can be overcome with appropriate design. Currently, most HWDs use electrical variable frequency drives (VFDs) [ 12 , 18 , 25 ] as standard. The SLE reelers also took the full tension of the hose or umbilical, resulting in diameter changes that were problematic for the level wind mechanism.…”