2016.07.10 – Finding space in the on board lab
After leaving Ponta Delgada, Azores, the Blue Mining team on cruise JC138 (#Bluemining) is now at full compliment. With the new arrivals comes a grab for every available Lab space. Did we bring too much gear? Certainly we have a lot of instruments and a very busy schedule.
As we approach the TAG area we start to look at the data collected by last month’s Blue Mining cruise M127, on board the R/V Meteor, and the maps produced by the AUV Abyss. These have a 50cm resolution and reveal the complex topography of the mounds in great detail, despite being at a depth of 3500m. Combined with seafloor video from Geomar’s HyBIS ROV from last month’s cruise, we are able to find a few small spots flat enough to land the RD2 sea floor drilling rig.
Despite having been studied for over 40 years, little is known about the sub-surface characteristics of the dead hydrothermal mineral deposits below the sea floor. This is because they have rarely been drilled. The sites we are heading for have never been drilled and only been visited a couple of times in the past by submersible and ROV. As a result, the drilling conditions are likely to be challenging, and we have to be fully prepared. The RD2 sea floor drilling team has bought a selection of drilling bits, including some new ones designed especially for the Blue Mining project. These include bits that are impregnated with diamonds, some of which are quite large. Don’t get too excited though, they are industrial diamonds and wouldn’t make a very sparkly ring. Never-the-less, each drill bit costs thousands of pounds and is ruined by the time we finish each hole.
Luckily we have expert advice to hand. Mike Wilson is the RD2 team leader and explains to us what the different bits are optimised for. Co-chiefs Sven and Paul listen intently as Mike explains that we should choose ‘that one’. A ‘bit for all occasions’.
The drilling lesson ends with Mike bringing up one of their bottom hole assemblies to the Science Lab. This is the tool that connects the core barrel to the drill bit and allows us to flush the hole with seawater to keep the drill bit cool as we drill beneath the ocean floor. It is quire clear to us just how complex the RD2 is and what extreme technological challenges we face in undertaking this expedition to drill beneath the Mid-Atlantic Ridge.