Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

Victoria University Antarctic Research Expedition Science and Logistics Reports 1998-99: VUWAE 43

Drill Site Science operations

Drill Site Science operations

  • Submarine Video. The umbilical of the video camera system was stressed and damaged this season. The system has a vital role in the sea riser embedment process and subsequent monitoring of the riser and sea floor as drilling proceeds. It is not clear at this time if the umbilical can be reliably repaired or if it will have to be replaced. Some other minor repairs will be required for 1999 operation including the building of umbilical/guide wire separators to reduce the risk of future umbilical damage.
  • Gas Detection. The sensors for this system will require calibration and minor changes made including a new larger gas sampling line with a heated section installed to reduce freezing problems and false readings. The current system detects both inflammable and hydrogen sulphide gases and does not distinguish the composition of the inflammable components. The current system is sufficient for the safety of the drilling operation and records gas events along with weather data at the drill site. If more sophisticated gas analysis is proposed I would consider this as a scientific study not required for general safety and drilling operations.
  • Core processing. Core processing and packaging worked well, with the split core- tube sections being used succesfully for retaining the integrity of unlithified or crumbly core when boxed. Minor modifications are planned for the core splitting saws. Consumables including plastic splits for soft core and diamond saw blades will have to be restocked for 1999. We hope to be able to package all CRP 3 core in plastic splits to reduce core damage and improve handling proceedures at the Crary Lab and core repositories.
  • Core orientation tool. This tool will require some modification to operate reliably at the bottom of a deep hole. The tool was only run once this season and damaged the core face at the bottom of the hole so that orientation marks were not recorded and the tool did not trigger. It also requires good hard core that is later continuously cored without loss and this is hard to predict. The deployment of this tool poses a problem in that it requires someone with time and appropriate skills to operate but more importantly requires a dedicated wire-line trip each time and so competes with coring time. I am aware that this allocation of time and the tools operation was not resolved well in 1998 and we intend to improve this in 1999 in conjunction with other experiments related to the in-situ stress studies- Core scan images. These images were provided as a service to the project by Dr Terry Wilson's group and were invaluable at the drill site especially during the process of sea riser advancement. The scanned images provide an immediately useable product that conventional photography cannot. The scanned images will also be reproduced in the initial reports.
  • GPS surveying. The GPS surveying of the drill site position in general went very well. A real-time correction signal was broadcast from the temporary Cape Roberts Hut Base Station (CRHBS) for the initial navigation and site selection during the WINFLY period. Subsequently all data was post processed against CRHBS data to give drill site positions with errors normally less than 0.5 m for sea ice offset calculations. The base station computer developed an intermittent fault during November resulting in three days of non-processable data at the end of drilling. This computer will have to be replaced for future page break work