I wonder if this is the same program that airs on History/HistIntl/Military channels. I've seen it a number of times, most recently this afternoon.
If so it's a combination of dramatic reenactment of the events of the boat's sinking and the modern day exploration of the wreck, in part to determine what environmental dangers it might pose due to the mercury on board.
Don't know any other sources for the story so I can't say how accurate the presentation is, but I find it compelling to watch.