From what I understand they have had to build this new cap pretty much from scratch, designed to handle the cold, based on the lessons they learned first from the failed “big box” fix, and the current cap.
in fact, they were originally going to get this new cap in place I thought right at the start of the month; my GUESS is that the failure they had last week when the rover ran into the hose has caused them to make some sort of design change — I don’t know this, maybe it’s just taking longer than expected.
As to why it took so long, ignoring the interference of our government, my guess is that at the start they didn’t really know they had such a problem, and they didn’t really understand that their traditional methods wouldn’t work. I think they were pretty sure dropping that big box on the well was going to stop the leaking, so they hadn’t put a lot of effort into any special caps (which at the time they couldn’t use because the pipe was still attached).
I believe your analysis of why they did not try current method from the start is probably pretty accurate. They did seem to think the big box would work. And the Robot collosion did put them back a bit.
I just listened to the Well's audio briefing for the 28th of last month where he described what the plans were. All of what they are planning to do will coincide with the relief well which will probably come in within a couple weeks of the new topper.
We used to call this a christmas tree. It is flange mounted and bolted to the flange that is currently under the cutoff pipe on top. From that, once installed and they get a chance to play with it for a while as to pressures and such, they can actually cut this well off 100%.
That would be best case scenario, but it fits the relief well kill plan like a glove because if the need to throttle the flow back, they can and the kill is much easier and faster. Normally a kill takes weeks, and they could do it in days with the christmas tree and worst case they could use the shutoff valve to kill it from the top and bottom at the same time. Add to that the pumping capacity they will soon have and.....
Talk about redundancy!
Anyway, this well will be killed within 6 weeks (weather permitting)and that I think you can take to the bank.