This is what the internet is for
Read this:
http://en.wikipedia.org/wiki/Cobalt#Occurrence (and Production underneath that)
So Cobalt is found with Copper and Nickel deposits. "The main ores of cobalt are cobaltite, erythrite, glaucodot and skutterudite". Since Copper is found in native form, it's not unreasonable to think that you can find it in that form on most rocky planets. But would you find the cobalt minerals there too?
Cobalt is found usualy with sulphur and arsenic. Looking up the minerals, we have skutterudite forming as a hydrothermal mineral ( http://webmineral.com/data/Skutterudite.shtml ), glaucodot as "Deep seated, high temperature hydrothermal deposits" (http://www.mindat.org/min-1709.html), erythrite as as secondary oxidation (i.e. weathering) product ( http://www.mindat.org/min-1407.html ), and cobaltite in "High temperature hydrothermal deposits and contact metamorphic rocks (http://webmineral.com/data/Cobaltite.shtml).
Why is that important? Because it tells us on what sort of planets we could find cobalt minerals. Fortunately in this case cobalt minerals are mainly hydrothermal in origin, which means that they will be found on planets that have (or had) volcanic activity and water (most planets will have water in them, even if they don't have oceans). Erythrite would only be found on planets that have volcanism, water, *and* earth-like atmosphere that will weather the other cobalt minerals into erythrite.
So with that in mind, you are probably safe to use the techniques described at:
http://en.wikipedia.org/wiki/Cobalt_extraction_techniques to extract the cobalt.
(I largely elaborated on all this to illustrate how it is possible to use a bit of geological knowledge and knowledge of minerals and mineral extraction here on Earth to figure out which environments on which planets would be likely to have specific minerals or elements. For example, people often put "Lanthanum deposits" on airless planets, but lanthanum is not found in "deposits" - it's concentrated in minerals in placer deposits, which require something to concentrate them (e.g. rivers), which means they are going to be found on worlds with atmosphere and some method to erode and deposit rocks).