Two exposures: one for the sky, one for water and foreground...a little overlapping in the masking process. That was the easy part.
I start with a color image, use the B&W adjustment tool and slide the blue slider all the way to the right..or pretty close to there.
Essentially, I make a contrast layer and really push the contrast hard to the right, then I make two exposure layers, one overexposed by + 1x and one under, generally somewhere in the - 2.5x and set the layer mask color to white as this becomes a subtractive process.
Going from hightlight adjustment to shadow adjustment, back and forth for lots of hours, you build your tonal range by subtracting either the over or underexposed areas. In the end, the contrast is slightly adjusted back to a more mid-range value.
It's quite tedious but if any of you are familiar with David Byrne's work, you'll see how much depth can be achieved using this method.
http://www.85mm.co.uk/
This is a detail of the bottom right corner.