right click on layer and "copy" as smart object (gives you two smart object raw layers independent of each other - if done wrong, one change to one, and that change affects other copy)
double click on the copy to open PS RAW and edit accordingly with high contrast, 75%-85% clarity slider, sharpen around 80-85% with .7 radius
add BW adjustment layer to the copy and adjust accordingly.
I wanna say you change the copy layer to blend mode "Luminosity" (but without program in front of me at work, I'll have to check with it when I get home - I'm better doing it than explaining it lol)
I think that's pretty much the logistics of it (of course, it won't work with EVERY image), but it has a lot to do with the lighting of the subject to get those harsh shadows.