Zimex has a few operations in various parts of Africa:-
I speak under correction,but I believe they have a Twin Otter in Libya
They have a deal with a local company in Algeria,Hassi Messaoud, operating as Star Aviation,B200,B1900,Twotters,and Pilatus Porters.WSorking conditions are pretty tough,but I believe the chaps are looked after pretty well.
There is also a setup in Angola,Luanda, where there is some local oil company involvment,B1900 operations.
Finally,there is a new contract starting in Kharthoum,not to sure of what the a/c type is.
Drop me a PM and I can put you in touch with one of the guys who works for the company.
Rgds
BB