Between a Rock and a Hard Place
Well, I spoke too soon. Something drastic happened that caused us to leave Hole J: we got stuck. The pipe got caught in the hole and wouldn’t rotate anymore. There were a few options of how to proceed, and by far the most exciting – although probably least efficient – was to use dynamite to sever the bottom parts of the pipe and just move on. Secretly that’s the one I was rooting for. But here what actually happened:
First they removed the core barrel so they could offset the ship to get a drill string connected. The drill string needed to be opened so they could deploy sinker bars to retrieve the core barrel (the core barrel is the thing that contains the sweet core we scientists desire). The core barrel needed to be removed and out of the way before they could send down the tools needed to activate the mechanical bit release. Once the bit was released, it would drop to the bottom of the hole. Then the drillers would try to free the drill string without the bit attached to pull out of the hole. I'm guess this had to be done because it was like when you put your hand too far through the cup holder in a movie theater seat. But you don't want to open your fist because then the candy will fall out...but then you're stuck. Just let go of the candy, and move on. If the drill string wouldn't release this way, it'd have to be severed and left behind: dynamite!
(un)fortunately...the drill string released on its own. No dynamite.
The drillers are limited with how hard they can pull to try to release the pipe. This is probably determined by the limited amount of stress on the entire drill pipe/other parts of the rig. They are also limited in the amount of rotational force they can use. When you spin something with the bottom part in a stuck location, you build up a lot of torque. The drillers can tell when this happens because the pipe will spin rapidly backwards and then suddenly stop rotating.
I really can't get over the scale of these processes. What had to be done to release a drill bit probably wasn't anything different from what a carpenter has to do...but this is 3 miles below us! Try doing something like that practically blind! I can't get over that.
Anyway, the point is: we had to move on. That hole was toast. But, we had some options. At the Operations Update Meeting yesterday, Kathy Gillis presented the entire team with 2 options and wanted to hear our thoughts. That was a pretty cool democratic way of handling the situation, and it felt nice to be included with decisions like that. So, I'll try to sum up each option as best I can:
Option 1 was to stay close to home and drill until we hit another fault zone, meaning trouble, and then move on again. This is exactly what just happened. We ran into trouble because about 100 meters down in this area, there are a bunch of fault zones. Try drilling into a crack in a block of wood...doesn't work out so well. But at least we'd get another decent amount of core...that we already have.
Pro: This area contains primitive rock, the stuff we came here for.
Con: Hole I and Hole J are only 10 meters apart, so we don't really know how the crust in this area is consolidated. Who knows if that cement we poured the other day leaked into an area just a few meters over. If we drill too close, we could impact Holes I and J. We also won't be able to go past 100 meters if we stay here.
Option 2 is to go to another flat part that we've dubbed The Shoulder...not to be confused with The Bench (where we've been drilling for the last few weeks), where we know based on surveying the area that it isn't a big rubble pit. A new spot can hardly present any worse drilling conditions than the ones we've already encountered, and who knows what other awesome stuff we'd find.
Pro: Going to another area 500 meters away...and 160 meters up would give us some regional perspective. If The Bench is a scarp (or a piece that fractured off and slipped down) then what we've been drilling here may be what we can drill 160 meters up. The scarp could be what fell from up above.
Con: Has potential to just be another pile of rubble like the last few holes. The rocks in this new area are not as primitive.
Very basically our options were: To continue to drill in an area where we KNOW we will have problems, or go to another area...that COULD potentially give us problems. Sounds promising, huh?
We have an accountability and obligation to get more gabbro since that's what we stated this expedition would specifically target. We need to find a solution that will help us most scientifically while being time efficient as well.
What would you have picked?
Also another note about scale: When they talk about rubble piles...they aren't referring to little tiny gravel pits...they mean giant boulders and blocks of rock over large fields. Insane.
By the end of the meeting, it sounded like there was a lot of excitement to go explore the shoulder. Worst case-scenario is we spent another 2 weeks at a hole up on the shoulder, and then we still have a week left to make a Hail-Mary decision. Perhaps coming back down to The Bench to collect more stuff...