I really like shooting in B+W cus i think that it shows a much more graphic image, it can change the entire vibe of a shot. But some things look better in black and white than others, so my only advice to you would be to be more selective with what you shoot in B+W. Once you start shooting with it more you will know what i mean. Also its a good idea that if you see somthing that you want to shoot B+W shoot in in colour as well so that you have an option if one of them looks bad. Just my 2 cents.
Overall yours are good though!
I think they are all good for b&w except for the second to last. As said, it is just too flat of an image and i don't think upping the contrast at all would help.
the last one is good. You hit the highlights and the darks and the contrast is pretty nicely done.
For the rest, however, (with a slight exception of the third), they look a bit flat for my tastes. I think the first would be just meh if you fixed it, but the second could be really nice. I would fiddle with the curves and contrast to see if you can get something you like. Also, possibly a slight sepia tone would give it more of a pronounced feel, but im not sure. Its something to try if you'd like.
cool shots though! i assume you were in Africa? what part?