I started a thread on this and wanted to post some information that I found here too: Thread: Sinkhole in Assumption Parish Louisana vs Hurrican Issac...who will win?

I found this article:
[link to www.examiner.com]

The last paragraph states:
A Mandatory Evacuation is in effect for Bayou Corne and Texas Brine's exploratory drilling into the cavern above the sinkhole, predicted to take forty days and forty nights, began last week but has not reached the cavern, yet.

That amount of time is something that just sticks out to me.